"The gateway effect, if it exists, has at least two potential and quite different sources (MacCoun, 1998). One interpretation is that it is an effect of the drug use itself (e.g., trying marijuana increases the taste for other drugs or leads users to believe that other substances are more pleasurable or less risky than previously supposed). A second interpretation stresses peer groups and social interactions. Acquiring and using marijuana regularly may lead to differentially associating with peers who have attitudes and behaviors that are prodrug generally, not only with respect to marijuana. One version of this is the possibility that those peers will include people who sell other drugs, reducing the difficulty of locating potential supplies. If the latter is the explanation, then legalization might reduce the likelihood of moving on to harder drugs compared to the current situation."

"This study of crash risk found a statistically significant increase in unadjusted crash risk for drivers who tested positive for use of illegal drugs (1.21 times), and THC specifically (1.25 times). However, analyses incorporating adjustments for age, gender, ethnicity, and alcohol concentration level did not show a significant increase in levels of crash risk associated with the presence of drugs. This finding indicates that these other variables (age, gender, ethnicity and alcohol use) were highly correlated with drug use and account for much of the increased risk associated with the use of illegal drugs and with THC.

"This study found a statistically significant association between driver alcohol level and crash risk both before and after adjustment for demographic factors. These findings were generally consistent with similar analyses conducted in prior crash risk studies. Findings from this study indicate that crash risk grows exponentially with increasing BrAC. The study shows that at low levels of alcohol (e.g., 0.03 BrAC) the risk of crashing is increased by 20 percent, at moderate alcohol levels (0.05 BrAC) risk increases to double that of sober drivers, and at a higher level (0.10 BrAC) the risk increases to five and a half times. At a BrAC of 0.15, the risk is 12 times, and by BrACs of 0.20+ the risk is over 23 times higher."

"Preliminary look at racial disparities in select counties of Washington

"The Crime, Cannabis & Police Research Group at Washington State University used preliminary data from a Department of Justice funded study to compare white vs. Black arrests.¹¹ Latinos were not included in the analysis, because of difficulties measuring ethnicity in arrest data. Their main preliminary findings are that after legalization in Washington, African Americans/Blacks continue to be disproportionally arrested for the possession and selling of marijuana when compared to whites. Though the disparity in marijuana possession between African American/Blacks and whites was reduced slightly after legalization, the disparity for selling marijuana has more than doubled since legalization.

"Local trends

"While statewide studies have the ability to control for individual law enforcement agencies or police departments, monitoring trends in marijuana-related crimes within a local police department can provide details of violations that statewide data systems do not. For example, violations for public consumption of marijuana cannot be directly queried from state-derived data; however, local law enforcement agencies and municipal courts maintain details on the nature of the crime that would indicate whether someone was ticketed for public consumption vs. possession or a different drug-related charge. One example of the potential of local data to explore issues of criminal justice can be made using data from the Seattle Police Department (SPD). A 2015 report for the Seattle Community Police Commission showed a disproportionate number of citations for marijuana public consumption issued to African Americans/Blacks in Seattle.¹² Using local police department data is key to understanding differences in the implementation and enforcement of polices pertaining to the legalization of marijuana."

"In these initial investigations, we found no evidence that I-502 enactment, on the whole, affected cannabis abuse treatment admissions. Further, within Washington State, we found no evidence that the amount of legal cannabis sales affected cannabis abuse treatment admissions.

"The bulk of outcome analyses in this report used the within-state approach to focus on identifying effects of the amount of legal cannabis sales. We found no evidence that the amount of legal cannabis sales affected youth substance use or attitudes about cannabis or drug-related criminal convictions.

"We did find evidence that higher levels of retail cannabis sales affected adult cannabis use in certain subgroups of the population. BRFSS respondents 21 and older who lived in counties with higher levels of retail cannabis sales were more likely to report using cannabis in the past 30 days and heavy use of cannabis in the past 30 days.

"We also found two effects that are difficult to interpret. Among the portion of the population aged 18 to 21, BRFSS respondents living in counties with higher sales were less likely to report using cannabis in the past 30 days, in some analyses. It may be that legal cannabis sales have made cannabis more difficult to access by persons below the legal age, for instance, by reducing black market supply through competition.

"We also found that in the portion of the BRFSS sample who smoked cigarettes, respondents living in counties with higher levels of legal cannabis sales were less likely to report past-month cannabis use. It is particularly difficult to explain why increased sales would lead to lower cannabis use among cigarette smokers."

"The public health burden of cannabis use is probably modest compared with that of alcohol, tobacco, and other illicit drugs. A recent Australian study⁹⁶ estimated that cannabis use caused 0·2% of total disease burden in Australia—a country with one of the highest reported rates of cannabis use. Cannabis accounted for 10% of the burden attributable to all illicit drugs (including heroin, cocaine, and amphetamines). It also accounted for around 10% of the proportion of disease burden attributed to alcohol (2·3%), but only 2·5% of that attributable to tobacco (7·8%)."

"Among the more common adverse effects is the cannabinoid hyperemesis syndrome (CHS), first reported in 2004 [6]. CHS is a syndrome of cyclic vomiting in the setting of chronic, high-dose cannabis use that is frequently associated with compulsive hot baths/showers, used in attempt to control symptoms.

"Patients with CHS present frequently to various health care settings with intractable nausea and vomiting. These patients often undergo expensive medical testing, may require hospital admission for symptom management, and often experience significant delays in diagnosis [7]. CHS is under-recognized due to a combination of factors including the paradoxical use for treatment of nausea and vomiting, the stigma associated with cannabis use, and the illegal status of cannabis in many regions leading to under-reporting of use. The frequency of emergency department visits and high rates of hospital admission for CHS exemplify the difficulty in symptom management. The lack of knowledge and treatment recommendations regarding CHS compounds this issue. Subsequently, CHS is a costly illness to manage. In an observational study of CHS patients followed over 2 years, the median charge for ED visits and hospital admissions was $95,023 (IQR = $62,420–$268,110) [7]."

"Assessing both CUD [Cannabis Use Disorder] and cannabis use status and their associations with suicidal ideation, plan, and attempt, we found that suicidality trends varied by sex, depression, and both CUD and cannabis use status. Our results suggest that CUD, daily cannabis use, and even nondaily cannabis use were associated with a higher prevalence of suicidal ideation, plan, and attempt more significantly in women than in men. Specifically, the adjusted prevalence of past-year suicidal ideation was higher among women with CUD regardless of MDE [Major Depressive Episode] status and among women without MDE but with daily or nondaily cannabis use compared with their male counterparts. We found upward trends in suicidal ideation among women (rather than men) with MDE and CUD or daily and nondaily cannabis use. Compared with their male counterparts, the adjusted prevalence of suicide plan and attempt were higher among women with MDE and CUD or daily cannabis use and among women without MDE but with CUD or daily and nondaily cannabis use. Similarly, from 2008 to 2019, we found an upward trend in suicide plan among women (rather than men) with MDE and daily cannabis use and an upward trend in suicide attempt among women (rather than men) with MDE and CUD. By contrast, among individuals with neither MDE nor cannabis use, the adjusted prevalence of suicidal ideation, plan, and attempt were similar between men and women, and the adjusted prevalence of suicidal ideation was lower among women with MDE without CUD or cannabis use compared with their male counterparts."

"Recreational cannabis legalization causes increases in mean cannabis frequency and residents of recreational states have fewer recent symptoms of AUD. Broadly speaking, our co-twin control and differential vulnerability results suggest that the impacts of recreational cannabis legalization on psychiatric and psychosocial outcomes are otherwise minimal. We assessed a broad range of outcomes, including other substance use, substance dependence, disordered personality, externalizing and legal issues, relationship agreement, workplace behavior, civic engagement, and cognition and found no detrimental nor protective effects for the majority of these domains, nor did we identify any increased vulnerability conferred by established risk factors."

"A total of 11 articles met the inclusion criteria for the metaanalysis (Figure 1): 7 for depression^{10,16,34,38,44-46}; 3 for anxiety,^16,38,44 3 for suicidal ideation,^41,47,57 and 3 for suicide attempts.^10,54,57 To estimate the extent to which cannabis use
during adolescence was associated with increased odds of developing depression in young adulthood, we pooled results from 7 studies.^{10,16,34,38,44-46} The pooled OR [Odds Ratio] for depression during young adulthood among cannabis users compared with nonusers was 1.37 (95% CI, 1.16-1.62; I2 = 0%; Figure 2). Cannabis use during adolescence was associated with increased odds of developing anxiety in young adulthood when pooling 3 studies^16,38,44 (OR, 1.18; 95% CI, 0.84-1.67; I2 = 42.0%; Figure 2). Suicidal ideation is a symptom of depression, while suicide represents one of the most severe sequelae of mental illness. Results from 3 studies that had measured the association of cannabis use during adolescence with subsequent suicidal ideation within adolescence^41,57 and in young adulthood⁴⁷ were pooled with a resultant OR of 1.50 (95% CI, 1.11-2.03; I2: 0%; Figure 3). For the number of suicide attempt outcomes within adolescence^54,57 or during young adulthood,¹⁰ the results were pooled with a resultant OR of 3.46 (95% CI, 1.53-7.84; I2 = 61.3%; Figure 3)."

In 2020, law enforcement agencies in the US made an estimated 7,632,473 arrests for all offenses, of which 1,155,610 were drug arrests.

Although the intent of a 'War on Drugs' may have been to target drug smugglers and 'King Pins,' of the 1,155,610 arrests for drug law violations in 2020, 86.7% (1,001,914) were for mere possession of a controlled substance. Only 13.3% (153,696) were for the sale or manufacturing of a drug. Further, 30.3% of drug arrests in 2020 were for marijuana offenses -- a total of 350,150. Of those, an estimated 317,793 arrests (27.5% of all drug arrests) were for marijuana possession alone. By contrast in 2000, a total of 734,497 Americans were arrested for marijuana offenses, of which 646,042 (40.9%) were for possession alone.

Table: Total Annual Arrests in the US by Year and Type of Offense, 1996-2020

"Several limitations of the present study should also be addressed. The PET data used in this study were collected on a separate sample of young adults, not the 799 youths who underwent longitudinal neuroimaging. Given the invasive nature of PET imaging and its associated risks, it is not ethical to collect PET data on minors. We cannot state definitively that, in our sample of 799 participants, the areas exhibiting cannabis-related thinning in longitudinal MRI analysis were, in fact, high in CB1 receptor availability. Our present findings are also limited by the self-report nature of our cannabis use measure. As with any self-report measure, it is possible that participants were not honest regarding their cannabis use or that their estimates of past cannabis use were inaccurate. We also did not have information pertaining to the types of cannabis products used (eg, cannabis oil concentrates and other formulations). As in other longitudinal MRI studies, there is uncertainty with regard to the exact neurobiological mechanisms associated with MRI-assessed cortical thinning. Research suggests that MRI-assessed, age-related cortical thinning may reflect increased myelination of lower cortical layers as opposed to synaptic pruning and/or neuronal cell loss.⁵⁷ Natu et al⁵⁷ found good correspondence between MRI-assessed cortical thickness and histologic measurements of cortical thickness among young adults. This latter finding is critical given that we detected cannabis-related differences in cortical thickness at age 19 years and not at 14 years, suggesting that our MRI-assessed cortical thickness findings are associated with reduced cortical gray matter rather than increased myelination. The present study focused on cortical thickness development and did not examine potential cannabis-related outcomes within subcortical structures. Future studies may benefit from conducting similar analyses on subcortical regions, particularly those rich in CB1 receptors. Most important, given the observational nature of the present study, it is possible that the apparent association between cortical thinning and cannabis use reflects preexisting trajectories of brain maturation that were not caused by cannabis use. We cannot rule out the possibility that preexisting cognitive and/or behavioral differences are associated with neurodevelopmental trajectories from adolescence to early adulthood and that cannabis use is not causally related to cerebral cortical thickness development."

"In summary, this study showed little, if any, effect of marijuana use on non-AIDS mortality in men and on total mortality in women. The increased risk of AIDS mortality in male marijuana users probably did not reflect a causal relationship, but most likely represented uncontrolled confounding by male homosexual behavior. The risk of mortality associated with marijuana use was lower than that associated with tobacco cigarette smoking."

"Our results indicate a moderate relation between early teen marijuana use and young adult abuse of other illicit substances; however, this association fades from statistical significance with adjustments for stress and life-course variables. Likewise, our findings show that any causal influence of teen marijuana use on other illicit substance use is contingent upon employment status and is short-term, subsiding entirely by the age of 21. In light of these findings, we urge U.S. drug control policymakers to consider stress and life-course approaches in their pursuit of solutions to the 'drug problem.'"

"The law enforcement view of marijuana was indelibly shaped by the fact that it was initially connected to brown people from Mexico and subsequently with black and poor communities in this country. Police in Texas border towns demonized the plant in racial terms as the drug of 'immoral' populations who were promptly labeled 'fiends.'

"As the legal scholars Richard Bonnie and Charles Whitebread explain in their authoritative history, 'The Marihuana Conviction,' the drug’s popularity among minorities and other groups practically ensured that it would be classified as a 'narcotic,' attributed with addictive qualities it did not have, and set alongside far more dangerous drugs like heroin and morphine.

"By the early 1930s, more than 30 states had prohibited the use of marijuana for nonmedical purposes. The federal push was yet to come.

"The stage for federal suppression of marijuana was set in New Orleans, where a prominent doctor blamed 'muggle-heads' — as pot smokers were called — for an outbreak of robberies. The city was awash in sensationalistic newspaper articles that depicted pushers hovering by the schoolhouse door turning children into 'addicts.' These stories popularized spurious notions about the drug that lingered for decades. Law enforcement officials, too, trafficked in the 'assassin' theory, under in which killers were said to have smoked cannabis to ready themselves for murder and mayhem."

"Breeders and producers of sweet corn go to great lengths to isolate their crops from the pollen of field corn. The same applies to hemp and marijuana. People who grow strains of Cannabis for smoking try to avoid pollination of the flowers. The superior quality material is obtained from seedless plants, the so-called “sinsemilla.”

"Hemp fields, in fact, could be a deterrent to marijuana growers. A strong case can be made that the best way to reduce the THC level of marijuana grown outdoors would be to grow industrial hemp near it. An experiment in Russia found that hemp pollen could travel 12 kilometers. This would mean that a hemp field would create a zone with a 12-kilometer radius within which no marijuana grower would want to establish a crop.

"The reciprocal also applies. Growers of hemp seed would not want Cannabis of an “off type” (i.e., not the intended genetic type) mixing its pollen with their flowers. The isolation of genotypes is a common procedure used by the seed industry to preserve the genetic integrity of varieties. Valued strains are created by plant breeding, at substantial expense. Marijuana pollen would destroy this value."

"Our findings show that past-year and past-month cannabis use among non-Hispanic White respondents ages 21 years or older consistently increased following recreational cannabis legalization, while past-year and past-month use remained unchanged among non-Hispanic Black participants. No changes in use were observed for any racial or ethnic group among individuals aged 12 to 20, for whom cannabis use remains illegal. Nevertheless, Black people were still 1.72 times more likely to be arrested for cannabis possession in states that legalized cannabis before 2018,⁹ indicating that racist and discriminatory targeting of Black people persists despite changing policies.^9,10"

"The THC levels in industrial hemp are so low that no one can get high from smoking it. Moreover, industrial hemp, while low in THC, is high in another kind of cannabinoid, CBD, which counteracts THC’s psychoactivity.

"As William M. Pierce Jr., Ph.D., Associate Professor of Pharmacology and Toxicology at the University of Louisville School of Medicine notes, “Industrial hemp does in fact contain a psychoactive substance, tetrahydrocannabinol (THC) and thus the question appears at first reading to be a reasonable one. Upon closer consideration, however, using the most fundamental principles of pharmacology, it can be shown that it is absurd, in practical terms, to consider industrial hemp useful as a drug.”²⁷

"According to Professor Pierce, to obtain a psychoactive effect with even 1 percent THC hemp (industrial hemp and feral hemp, the wild hemp the DEA aggressively harvests and burns²⁸, contain less than 0.5% percent THC29 ), would require the user to smoke 10-12 cigarettes containing hemp in a “very short period of time. . . . This large volume (and) high temperature inhalation of vapor, gas, and smoke would be difficult for a person to withstand, much less enjoy.” Professor Pierce goes on to note that anyone who ate hemp hoping to get “high” would be consuming the fiber equivalent of several doses of a high-fiber laxative. In other words, the very unpleasant side effects would dissuade anyone from trying to use industrial hemp as a drug.

"Dr. Pierce points out that beer sold as “nonalcohol” contains measurable alcohol. So does mouthwash. Even nutmeg contains a psychoactive substance. But the authorities are not aggressively concerned about the abuse of these products because the side effects are so severe as to discourage such abuse.

"Critics have alleged that the marijuana of the sixties had THC levels comparable to those of industrial hemp. But when Lynn Zimmer, Ph.D., and John Morgan, M.D., examined this assertion they found it lacked substance."

"Daily marijuana use held steady at 6.8% in 2015 among young adults, but that is triple the rate in 1992 (2.3%), the low point since estimates for this age group first became available in 1986. The 2014 and 2015 rates are the highest levels of daily use ever observed in this young adult population since tracking of their use began 29 years ago."

Click here for complete datatable of Thirty-Day Prevalence of Daily Marijuana, Alcohol, and Tobacco Use Among 19-30 Year Olds in the US

"In 2009-2010, past month marijuana use was reported by 6.8 percent of the U.S. population aged 12 years or older, an increase from 6.4 percent in 2008-2009 (Table C.3). Nine States that were in the top fifth for past month illicit drug use among persons aged 12 or older also were ranked in the top fifth for past month marijuana use: Alaska, Colorado, District of Columbia, Maine, Massachusetts, New Hampshire, Oregon, Rhode Island, and Vermont (Figures 2.1 and 2.9).

"Seven States were ranked in the top fifth for past month marijuana use in age groups 12 to 17, 18 to 25, 26 or older, and 12 or older: Colorado, Maine, Massachusetts, New Hampshire, Oregon, Rhode Island, and Vermont (Figures 2.9 to 2.12). The rate of past month marijuana use in the 12 or older population ranged from 3.1 percent in Utah to 11.8 percent in Alaska (Table B.3). Utah had the lowest rate in all age groups. Between 2008-2009 and 2009-2010, past month marijuana use among persons 12 or older increased in 10 States: Colorado, District of Columbia, Idaho, Illinois, Massachusetts, Michigan, New Mexico, Oklahoma, Texas, and Washington (Table C.3). During the same time period, past month marijuana use increased in one State among 12 to 17 year olds (District of Columbia), eight States among 18 to 25 year olds (Florida, Illinois, Iowa, New Mexico, North Carolina, Oklahoma, Pennsylvania, and Washington), and four States among persons aged 26 or older (District of Columbia, Idaho, Michigan, and Texas). Decreases only occurred in two States: Tennessee, among persons aged 12 or older, and Utah, among youths aged 12 to 17. All four census regions had higher rates of past month marijuana use among persons aged 12 or older in 2009-2010 compared with 2008-2009."

"For Michele Leonhart, the administrator of the Drug Enforcement Administration, there is no difference between the health effects of marijuana and those of any other illegal drug. 'All illegal drugs are bad for people,' she told Congress in 2012, refusing to say whether crack, methamphetamines or prescription painkillers are more addictive or physically harmful than marijuana.

"Her testimony neatly illustrates the vast gap between antiquated federal law enforcement policies and the clear consensus of science that marijuana is far less harmful to human health than most other banned drugs and is less dangerous than the highly addictive but perfectly legal substances known as alcohol and tobacco. Marijuana cannot lead to a fatal overdose. There is little evidence that it causes cancer. Its addictive properties, while present, are low, and the myth that it leads users to more powerful drugs has long since been disproved.

"That doesn’t mean marijuana is harmless; in fact, the potency of current strains may shock those who haven’t tried it for decades, particularly when ingested as food. It can produce a serious dependency, and constant use would interfere with job and school performance. It needs to be kept out of the hands of minors. But, on balance, its downsides are not reasons to impose criminal penalties on its possession, particularly not in a society that permits nicotine use and celebrates drinking."

In 2015:
an estimated 117,865,000 people aged 12 or older in the US had tried marijuana at least once in their lifetimes.
an estimated 36,043,000 people aged 12 or older in the US had tried marijuana at least once in the past year.
an estimated 22,226,000 people aged 12 or older in the US had tried marijuana at least once in the past month.

Table: Marijuana Use in Lifetime, Past Year, and Past Month among Persons in the US Aged 12 or Older, by Demographic Characteristics: Number in Thousands

"Although individual lifetime risk of chronic psychotic disorders such as schizophrenia, even in people who use cannabis regularly, is likely to be low (less than 3%), cannabis use can be expected to have a substantial effect on psychotic disorders at a population level because exposure to this drug is so common."

According to the Substance Abuse and Mental Health Service's Treatment Episode Data Set, in 2015 in the US there were 213,001 admissions to treatment with marijuana reported as the primary substance of abuse out of the total 1,537,025 admissions to treatment in the US for those aged 12 and older for all substances that year. This is the lowest number of marijuana admissions and total treatment admissions in at least a decade: marijuana admissions peaked in 2009 at 373,338, and total admissions peaked in 2008 at 2,074,974.

"CUD [Cannabis Use Disorder] is defined in the DSM-5 as a problematic pattern of cannabis use leading to clinically significant impairment or distress occurring within a 12-month period as manifested by cannabinoid tolerance and withdrawal; increasing amounts of cannabis use over time; inability to control consumption; craving; and recurrent cannabis use having negative implications on social, professional and educational life [3]. Withdrawal symptoms usually appear approximately 24 hours after abstinence initiation, peak within two to six days and remit within two weeks [4]. Symptoms may include irritability, anger or aggression; nervousness or anxiety; sleep difficulty (insomnia, disturbing dreams); decreased appetite or weight loss; restlessness; depressed mood; or physical discomforts (abdominal pain, shakiness/tremors, fever, chills or headache) [5, 6, 7•]. Withdrawal is diagnosed if at least three of these symptoms develop. A week after cessation of use, additional symptoms may appear such as fatigue, yawning, difficulty in concentration, and rebound periods of increased appetite or hypersomnia [3]."

"First, the use of cannabis and rates of psychotic symptoms were related to each other, independently of observed/non-observed fixed covariates and observed time dynamic factors (Table 2). Secondly, the results of structural equation modeling suggest that the direction of causation is that the use of cannabis leads to increases in levels of psychotic symptoms rather than psychotic symptoms increasing the use of cannabis. Indeed, there is a suggestion from the model results that increases in psychotic symptoms may inhibit the use of cannabis."

"The issues of measurement and conceptualization described above in relation to efforts to screen for problematic or harmful cannabis use highlight the shortcomings of ‘one-size-fits-all’ approaches to screening. Our examination of the existing literature and of cannabis users from a general population study and from a mixed-methods study of adult, stable, socially integrated users suggests that many cannabis users who may otherwise meet the criteria for being at moderate risk for problematic use are nonetheless able to successfully integrate cannabis use into everyday life with few associated problems. Indeed, our findings advocate that regular use of small amounts of cannabis does not appear to increase an individual’s likelihood of experiencing problems, and it does not threaten one’s ability to function well and perform expected roles. Even so, the tools used to assess potentially harmful cannabis use invariably serve to classify almost all ‘regular’ users as problematic users."

"Synthetic cannabinoids are substances chemically produced to mimic tetrahydrocannabinol (THC), the active ingredient in marijuana. When these substances are sprayed onto dried herbs and then consumed through smoking or oral ingestion, they can produce psychoactive effects similar to those of marijuana.²⁰ Synthetic cannabinoids were first produced for research purposes to study the effects of cannabinoids on brain functioning and their efficacy in treating pain.

"The DEA has indicated that the primary users of these synthetic substances are youth who purchase the substances online or in gas stations, convenience stores, smoke shops, and head shops.²¹ The substances are often sold as herbal incense, and common brand names under which synthetic cannabinoids are marketed are 'Spice' and 'K2.' Other names include 'Blaze,' 'Red X Dawn,' 'Genie,' and 'Zohai,' among others.²²

"Clemson University Professor John Huffman is credited with first synthesizing some of the cannabinoids, such as JWH-018, now used in 'fake pot' substances such as K2. The effects of JWH-018 can be 10 times stronger than those of THC. Dr. Huffman is quoted as saying, 'These things are dangerous—anybody who uses them is playing Russian roulette. They have profound psychological effects. We never intended them for human consumption.'²³ While synthetic cannabinoids may be used with the intention of getting a marijuana-like high, their actual effects are not yet known. Some reported effects of synthetic cannabinoids, such as relaxation and reduced blood pressure, are consistent with effects of marijuana. Other reported effects, such as nausea, increased agitation, elevated blood pressure, and racing heart rates, are not.²⁴ The Centers for Disease Control and Prevention (CDC) has noted epidemiological links between synthetic cannabinoid use and acute kidney injury.²⁵ In at least one case, synthetic cannabinoid use has been blamed for a fatality when an Iowa teen committed suicide reportedly following a K2- induced panic attack.²⁶ In the summer of 2014, the New York City (NYC) Department of Health issued a warning to the public regarding the dangers of synthetic cannabinoid use after 15 people experienced 'severe adverse reactions after suspected ingestion of synthetic cannabinoids' over a period of three days.²⁷ In 2015, following a 'tenfold increase in medical emergencies from synthetic marijuana' in New York State (NYS) in the summer of 2015 compared to the summer of 2014, Governor Cuomo announced passage of emergency NYS Health Department regulations to combat the sale of these drugs—these emergency regulations included the addition of two classes of chemical compounds to the banned substances list.²⁸"

"Police departments deploy most patrol and narcotics police to certain neighborhoods, usually designated "high crime." These are disproportionately low-income, and disproportionately African-American and Latino neighborhoods. It is in these neighborhoods where the police make most patrols, and where they stop and search the most vehicles and individuals, looking for "contraband" of any type in order to make an arrest. The item that young people in any neighborhood are most likely to possess, which can get them arrested, is a small amount of marijuana. In short, the arrests are racially-biased mainly because the police are systematically "fishing" for arrests in only some neighborhoods, and methodically searching only some "fish."⁵ This produces what has been termed "racism without racists."⁶"

"The lead researcher in the Christchurch study, Professor David Fergusson, said the role of cannabis in psychosis was not sufficient on its own to guide legislation. 'The result suggests heavy use can result in adverse side-effects,' he said. 'That can occur with ( heavy use of ) any substance. It can occur with milk.' Fergusson's research, released this month, concluded that heavy cannabis smokers were 1.5 times more likely to suffer symptoms of psychosis that non-users. The study was the latest in several reports based on a cohort of about 1000 people born in Christchurch over a four-month period in 1977. An effective way to deal with cannabis use would be to incrementally reduce penalties and carefully evaluate its impact, Fergusson said. 'Reduce the penalty, like a parking fine. You could then monitor ( the impact ) after five or six years. If it did not change, you might want to take another step.'

"The central finding gleaned from the present study was that MML [Medical Marijuana Legalization] is not predictive of higher crime rates and may be related to reductions in rates of homicide and assault. Interestingly, robbery and burglary rates were unaffected by medicinal marijuana legislation, which runs counter to the claim that dispensaries and grow houses lead to an increase in victimization due to the opportunity structures linked to the amount of drugs and cash that are present. Although, this is in line with prior research suggesting that medical marijuana dispensaries may actually reduce crime in the immediate vicinity [8]."

"Given that the current results failed to uncover a crime exacerbating effect attributable to MML [Medical Marijuana Legalization], it is important to examine the findings with a critical eye. While we report no positive association between MML and any crime type, this does not prove MML has no effect on crime (or even that it reduces crime). It may be the case that an omitted variable, or set of variables, has confounded the associations and masked the true positive effect of MML on crime. If this were the case, such a variable would need to be something that was restricted to the states that have passed MML, it would need to have emerged in close temporal proximity to the passage of MML in all of those states (all of which had different dates of passage for the marijuana law), and it would need to be something that decreased crime to such an extent that it ‘‘masked’’ the true positive effect of MML (i.e., it must be something that has an opposite sign effect between MML [e.g., a positive correlation] and crime [e.g., a negative correlation]). Perhaps the more likely explanation of the current findings is that MML laws reflect behaviors and attitudes that have been established in the local communities. If these attitudes and behaviors reflect a more tolerant approach to one another’s personal rights, we are unlikely to expect an increase in crime and might even anticipate a slight reduction in personal crimes."

"The withdrawal syndrome associated with dronabinol, the API [Active Pharmaceutical Ingredient] in Marinol®, produces symptoms in humans such as restlessness, irritability, mild agitation, anxiety, anger, insomnia, sleep EEG disturbances, nausea, decreased appetite, and decreased weight. Since a withdrawal syndrome is indicative of physical dependence, it is reasonable to conclude that generic dronabinol products (both naturally-derived [from the cannabis plant] or synthetically produced, and in hard or soft gelatin capsules) in sesame oil, will also produce physical dependence similar to those produced by Marinol®."

"Although marijuana grown in the United States was once considered inferior because of a low concentration of THC, advancements in plant selection and cultivation have resulted in higher THC-containing domestic marijuana. In 1974, the average THC content of illicit marijuana was less than one percent. Today most commercial grade marijuana from Mexico/Columbia and domestic outdoor cultivated marijuana has an average THC content of about 4 to 6 percent. Between 1998 and 2002, NIDA-sponsored Marijuana Potency Monitoring System (MPMP) analyzed 4,603 domestic samples. Of those samples, 379 tested over 15 percent THC, 69 samples tested between 20 and 25 percent THC and four samples tested over 25 percent THC."

"In conclusion, our results suggest that participation in the use of both licit and illicit drugs is price sensitive. Participation is sensitive to own prices and the price of the other drugs. In particular, we conclude that cannabis and cigarettes are complements, and there is some evidence to suggest that cannabis and alcohol are substitutes, although decriminalization of cannabis corresponds with higher alcohol use. Alcohol and cigarettes are found to be complements."

Click here for complete datatable of THC Potency of Tested Cannabis from Federal Seizure and State and Local Eradication Samples, by Type, 1985-2014.

"Data on the THC content of cannabis products in the USA have been collected by ElSohly et al. (1984, 2000) for many years as part of the University of Mississippi Potency Monitoring Project. Samples were submitted by law enforcement agencies and it has to be assumed that they were representative of the market. Mean THC values are shown in Figure 16 for normal herbal cannabis, sinsemilla and resin. The anomalously high value for resin in 1997 (19.24 %) has been excluded; it was based on only five values and is over nine standard deviations above the mean potency for the period 1980–1996. Although there has been an increase in the potency of herbal cannabis over the twenty-five-year period, cannabis resin (and hash oil) showed no long-term trends since 1980 when data were first collected. Although the potency of sinsemilla showed a clear upward trend in the final three years of the study, no such trend was obvious when the longer period of 1980–1995 is examined, particularly in view of the wide variations in potency that occurred from year to year (ElSohly et al., 2000). The THC content of herbal cannabis increased from around 1% before 1980 to around 4% in 1997. This increase, when seen in the European context, is deceptive. Before 1980, all mean herbal cannabis THC levels in the ElSohly study were less than 2.4%. By contrast, and as shown in Figure 10, comparable levels at that time in the United Kingdom were twice as great. In other words, it must be assumed that the quality of herbal cannabis consumed in the USA more than twenty years ago was unusually poor, but that in recent years it has risen to levels typical of Europe. So even the modest increase found by ElSohly et al. (2000) may be less significant than it seems. A recent analysis of cannabis seized in Florida in 2002 (Newell, 2003) showed amounts of THC found in samples ranging from 1.41% to 12.62%; the average THC content was 6.20%, which is almost identical to the 2002 value reported by the University of Mississippi Potency Monitoring Project."

"Despite continuing increases in the amount of cannabis produced domestically, much of the marijuana available within the United States is foreign-produced. The two primary foreign source areas for marijuana distributed within the United States are Canada and Mexico. Mexican drug trafficking organizations (DTOs) have relocated many of their outdoor cannabis cultivation operations in Mexico from traditional growing areas to more remote locations in central and northern Mexico, primarily to reduce the risk of eradication and gain easier access to U.S. drug markets. Asian criminal groups are the primary producers of high-potency marijuana in Canada."

"Tetrahydrocannabinol is a very safe drug. Laboratory animals (rats, mice, dogs, monkeys) can tolerate doses of up to 1000 mg/kg (milligrams per kilogram). This would be equivalent to a 70 kg person swallowing 70 grams of the drug —about 5,000 times more than is required to produce a high. Despite the widespread illicit use of cannabis there are very few if any instances of people dying from an overdose."

"There are health risks of cannabis use, most particularly when it is used daily over a period of years or decades. Considerable uncertainty remains about whether these effects are attributable to cannabis use alone, and about what the quantitative relationship is between frequency, quantity and duration of cannabis use and the risk of experiencing these effects.
"On existing patterns of use, cannabis poses a much less serious public health problem than is currently posed by alcohol and tobacco in Western societies."

In 1988, the DEA's Administrative Law Judge, Francis Young, concluded: "In strict medical terms marijuana is far safer than many foods we commonly consume. For example, eating 10 raw potatoes can result in a toxic response. By comparison, it is physically impossible to eat enough marijuana to induce death. Marijuana in its natural form is one of the safest therapeutically active substances known to man. By any measure of rational analysis marijuana can be safely used within the supervised routine of medical care."

"Of the approximately 2.5 million drug misuse or abuse ED visits that occurred during 2011, a total of 1,252,500, or just over half (50.9%), involved illicit drugs (Table 4). A majority (56.3%) of illicit drug ED visits involved multiple drugs. Overall, 27.9 percent of visits involving illicit drugs also involved alcohol.
"Cocaine and marijuana were the most commonly involved drugs, with 505,224 ED visits (40.3%) and 455,668 ED visits (36.4%), respectively. Cocaine and marijuana were followed by heroin, at 258,482 ED visits, or 20.6 percent, and then by amphetamines/methamphetamine, at 159,840 visits, or 12.8 percent."

Note: According to the DAWN report, "DAWN captures drugs that are explicitly named in the medical record as being involved in the ED visit. The relationship between the ED visit and the drug use need not be causal. That is, an implicated drug may or may not have directly caused the condition generating the ED visit; the ED staff simply named it as being involved." (p. 15)

"In this 20-year study of marijuana and pulmonary function, we confirmed the expected reductions in FEV1 [Forced expiratory volume in the first second of expiration] and FVC [forced vital capacity] from tobacco use. In contrast, marijuana use was associated with higher FEV1 and FVC at the low levels of exposure typical for most marijuana users. With up to 7 joint-years of lifetime exposure (eg, 1 joint/d for 7 years or 1 joint/wk for 49 years), we found no evidence that increasing exposure to marijuana adversely affects pulmonary function. This association, however, was nonlinear: at higher exposure levels, we found a leveling off or even a reversal in this association, especially for FEV1. Although our sample contained insufficient numbers of heavy users to confirm a detrimental effect of very heavy marijuana use on pulmonary function, our findings suggest this possibility."

"We found that moderate marijuana use was significantly associated with reduced risk of HNSCC [head and neck squamous cell carcinoma]. This association was consistent across different measures of marijuana use (marijuana use status, duration, and frequency of use). Diminished risk of HNSCC did not differ across tumor sites, or by HPV [human papillomavirus] 16 antibody status. Further, we observed that marijuana use modified the interaction between alcohol and cigarette smoking, resulting in a decreased HNSCC risk among moderate smokers and light drinkers, and attenuated risk among the heaviest smokers and drinkers."

"Despite several lines of evidence suggesting the biological plausibility of marijuana use being carcinogenic (1), it is possible that marijuana use does not increase cancer risk, as suggested in the recent commentary by Melamede (26). Although the adjusted ORs <1 may be chance findings, they were observed for all non-reference exposure categories with all outcomes except oral cancer. Although purely speculative, it is possible that such inverse associations may reflect a protective effect of marijuana. There is recent evidence from cell culture systems and animal models that 9-tetrahydrocannabinol, the principal psychoactive ingredient in marijuana, and other cannabinoids may inhibit the growth of some tumors by modulating key signaling pathways leading to growth arrest and cell death, as well as by inhibiting tumor angiogenesis (27-29). These antitumoral associations have been observed for several types of malignancies including brain, prostate, thyroid, lung, and breast."

"Our analyses of adults aged 20-59 years in the NHANES [National Health and Nutrition Examination Survey] III database showed that participants who used marijuana had lower prevalence of DM [Diabetes Mellitus] and had lower odds of DM relative to non-marijuana users. We did not find an association between the use of marijuana and other chronic diseases, such as hypertension, stroke, myocardial infarction and heart failure. This could be due to the smaller prevalence of stroke, myocardial infarction and heart failure in the examined age group.
"We noted the lowest prevalence of DM in current light marijuana users, with current heavy marijuana users and past users also having a lower prevalence of DM than non-marijuana users. The finding that past marijuana users had lower odds of prevalent DM than non-users suggests that early exposure to marijuana may affect the development of DM and a window of time of marijuana exposure earlier in life could be a factor to study. Similarly, our findings of a significant association between marijuana use and DM was only found in those aged $40 years suggest that the possibility of some protection from marijuana use may require many years before they become manifested. By contrast, it could reflect the increased prevalence of DM with age and the ability to detect an association with a lesser sample size when there is a greater cohort at risk for DM. The possible association of light marijuana use with decreased DM is similar to that of alcohol on DM and the metabolic syndrome, in which mild alcohol use was associated with lower prevalence of DM and the metabolic syndrome,^{14 15} and higher alcohol use associated with higher prevalence of DM and the metabolic syndrome.^{14 16}"

"People who develop problems with marijuana may indeed be different from those who do not, but this phenomenon has been observed with other substances of abuse. A comparison with alcohol use and dependence provides a case in point. The great majority of Americans have tried alcohol and continue to drink alcoholic beverages regularly. However, only an estimated 10 to 15 percent of alcohol drinkers develop problems, and only some of these problem drinkers seek treatment. This is also true of those who have tried cocaine or heroin (Anthony, Warner, and Kessler, 1994).

"That said, the experience of dependence on marijuana tends to be less severe than that observed with cocaine, opiates, and alcohol (Budney, 2006; Budney et al., 1998). On average, individuals with marijuana dependence meet fewer DSM dependence criteria; the withdrawal experience is not as dramatic; and the severity of the associated consequences is not as extreme. However, the apparently less severe nature of marijuana dependence does not necessarily mean that marijuana addiction is easier to overcome. Many factors besides a drug’s physiological effects—including availability, frequency and pattern of use, perception of harm, and cost—can contribute to cessation outcomes and the strength of addiction. The low cost of marijuana, the typical pattern of multiple daily use by those addicted, the less dramatic consequences, and ambivalence may increase the difficulty of quitting. Although determining the relative difficulty of quitting various substances of abuse is complex, the treatment literature reviewed here suggests that the experience of marijuana abusers rivals that of those addicted to other substances."

"Differences in cannabis smoking behaviour may also represent different risks for cannabis dependence independently of total THC exposure. Similar to cigarette smokers [16,21–24], cannabis smokers typically gradually decrease the puff volume and puff duration during the course of one joint, whereas puff velocity and interpuff interval gradually increase [20]. Interestingly, in a 2-year prospective study, nicotine dependence has been shown to develop more rapidly in tobacco smokers who smoke with stable or increasing puff volume and increasing puff duration ('atypical' smoking) [16]. One interpretation of this finding is that the risk of becoming nicotine-dependent is lower in smokers who reach nicotine saturation before the cigarette is finished and decrease their pace of smoking. If this mechanism also applies to cannabis smoking, one may expect that the risk for and the severity of cannabis dependence is associated with 'atypical' cannabis smoking."

"This study among 98 experienced cannabis smokers is the first naturalistic study to examine whether users of cannabis with high THC concentration titrate the psychoactive effects by using lower doses and/or by reduced inhalation, and whether cannabis smoking behaviour (topography) predicts cannabis dependence severity independently of total THC exposure.
"In contrast to our hypothesis, there was a positive association between cannabis THC concentration and cannabis dose, indicating that users of stronger cannabis generally used larger amounts of cannabis to prepare their regular joint. However, in line with our hypothesis, the negative association between THC concentration of joints and total inhaled smoke volume indicates that users of stronger joints inhaled smaller smoke volumes, thus resulting in partial titration of the total THC exposure. Overall, as exemplified by the comparison of the average user with the user with the maximum THC concentration, users of high-potency cannabis will generally be exposed to higher total doses of THC (at least in this sample). This is in line with Cappell et al.’s observations through a one-way mirror experiment in 1973 where users only partly adapted their intake [14]. Indeed, increased THC concentrations of cannabis have recently been linked to increased internal THC exposure assessed in blood [28]."

"An abstinence syndrome has been reported after the abrupt discontinuation of dronabinol [Marinol®] in volunteers receiving dosages of 210 mg/day for 12 to 16 consecutive days. Within 12 hours after discontinuation, these volunteers manifested symptoms such as irritability, insomnia, and restlessness. By approximately 24 hours post-dronabinol discontinuation, withdrawal symptoms intensified to include 'hot flashes', sweating, rhinorrhea, loose stools, hiccoughs and anorexia.
"These withdrawal symptoms gradually dissipated over the next 48 hours. Electroencephalographic changes consistent with the effects of drug withdrawal (hyperexcitation) were recorded in patients after abrupt dechallenge. Patients also complained of disturbed sleep for several weeks after discontinuing therapy with high dosages of dronabinol."

"Patterns in progression of drug use from adolescence to adulthood are strikingly regular. Because it is the most widely used illicit drug, marijuana is predictably the first illicit drug most people encounter. Not surprisingly, most users of other illicit drugs have used marijuana first. In fact, most drug users begin with alcohol and nicotine before marijuana, usually before they are of legal age."

"In summary, the notion that cannabis use itself is causally related to lower IQ and poorer educational performance was not supported in this large teenage sample. However, this study indeed has limitations, in particular the young age of outcome assessment. While we have demonstrated that confounding may be an explanation for links between cannabis use and poorer outcomes, large prospective cohorts tracking young people prior to, during and after stopping cannabis use, using more objective measures of drug use (e.g. the new NIH-funded ‘ABCD study’ in the United States; National Institute on Drug Abuse, 2015) are required before we can make strong conclusions. Cigarette smoking in particular has once again (Hooper et al., 2014; McCaffrey et al., 2010; Silins et al., 2014; Stiby et al., 2014) been highlighted as an important factor in adolescent outcomes, as well as a robust independent predictor of educational performance, and the reasons for this need to be elucidated."

"In the present study, the most persistent adolescent-onset cannabis users evidenced an average 8-point IQ decline from childhood to adulthood. Quitting, however, may have beneficial effects, preventing additional impairment for adolescent-onset users. Prevention and policy efforts should focus on delivering to the public the message that cannabis use during adolescence can have harmful effects on neuropsychological functioning, delaying the onset of cannabis use at least until adulthood, and encouraging cessation of cannabis use particularly for those who began using cannabis in adolescence."

"Nevertheless, when considering all 15 studies (i.e., those that met both strict and more relaxed criteria) we only noted that regular cannabis users performed worse on memory tests, but that the magnitude of the effect was very small. The small magnitude of effect sizes from observations of chronic users of cannabis suggests that cannabis compounds, if found to have therapeutic value, should have a good margin of safety from a neurocognitive standpoint under the more limited conditions of exposure that would likely obtain in a medical setting."

"Our findings suggest that regular cannabis use before age 18 y predicts impairment, but others have found effects only for younger ages ^{(10, 15)}. Given that the brain undergoes dynamic changes from the onset of puberty through early adulthood ^{(37, 38)}, this developmental period should be the focus of future research on the age(s) at which harm occurs."

"Current marijuana use had a negative effect on global IQ score only in subjects who smoked 5 or more joints per week. A negative effect was not observed among subjects who had previously been heavy users but were no longer using the substance. We conclude that marijuana does not have a long-term negative impact on global intelligence. Whether the absence of a residual marijuana effect would also be evident in more specific cognitive domains such as memory and attention remains to be ascertained."

"These results can be interpreted in several ways. A statistically reliable negative effect was observed in the domain of learning and forgetting, suggesting that chronic long-term cannabis use results in a selective memory defect. While the results are compatible with this conclusion, the effect size for both domains was of a very small magnitude. The "real life" impact of such a small and selective effect is questionable. In addition, it is important to note that most users across studies had histories of heavy longterm cannabis consumption. Therefore, these findings are not likely to generalize to more limited administration of cannabis compounds, as would be seen in a medical setting."

"One of the major concerns about the psychological effects of chronic heavy cannabis use has been that it impairs adult motivation. The evidence for an 'amotivational syndrome' among adults consists largely of case histories and observational reports (e.g. Kolansky and Moore, 1971; Millman and Sbriglio, 1986). The small number of controlled field and laboratory studies have not found compelling evidence for such a syndrome (Dornbush, 1974; Negrete, 1983; Hollister, 1986). The evidential value of the field studies is limited by their small sample sizes, and the limited sociodemographic characteristics of their samples, while the evidential value of the laboratory studies is limited by the short periods of drug use, the youthful good health of the volunteers, and minimal demands made on volunteers in the laboratory (Cohen, 1982). Some regular cannabis users report a loss of ambition and impaired school and occupational performance as adverse effects of their use (e.g. Hendin et al, 1987) and that some ex-cannabis users give impaired occupational performance as a reason for stopping (Jones, 1984). Nonetheless, it is doubtful that cannabis use produces a well defined amotivational syndrome. It may be more parsimonious to regard the symptoms of impaired motivation as symptoms of chronic cannabis intoxication rather than inventing a new psychiatric syndrome."

"Laboratory studies also find no link between THC intoxication and violence. Most people who ingest THC before performing a competitive task in the laboratory do not show more aggression than people who receive placebos; occasionally they show decreased hostility. Numerous scientific panels sponsored by various governments invariably report that marijuana does not lead to violence.(751)"

"Annual marijuana prevalence peaked among 12th graders in 1979 at 51%, following a rise that began during the 1960s. Then use declined fairly steadily for 13 years, bottoming at 22% in 1992—a decline of more than half. The 1990s, however, saw a resurgence of use. After a considerable increase (one that actually began among 8th graders a year earlier than among 10th and 12th graders), annual prevalence rates peaked in 1996 at 8th grade and in 1997 at 10th and 12th grades. After these peak years, use declined among all three grades through 2007 or 2008. After these declines, an upturn occurred in use in all three grades, lasting for three years in the lower grades and longer in grade 12. Annual marijuana prevalence among 8th graders increased in use from 2007 to 2010, decreased slightly from 2010 to 2012, and then declined significantly in 2016. Among 10th graders, use increased somewhat from 2008 to 2013 and then declined after that. Among 12th graders, use increased from 2006 to 2011 and then held level through 2016. As shown in Table 8, daily use increased in all three grades after 2007, reaching peaks in 2011 (at 1.3% in 8th), 2013 (at 4.0% in 10th), and 2011 (at 6.6% in 12th), before declining slightly since. Daily prevalence rates in 2016 were 0.7%, 2.5%, and 6.0%, respectively, with one in seventeen 12th graders smoking daily."

"Teens also say they are seeing more peers in school smoking marijuana and more teens (73 percent) report having friends who smoke marijuana regularly (71 percent) – significantly higher than four years ago. Since 2008, there have also been significant declines in teen perceptions that they will lose respect, harm themselves, or mess up their lives if they use marijuana."

"The proportion of students seeing great risk from using marijuana regularly fell during the rise in use in the 1970s, and again during the subsequent rise in the 1990s. Indeed, at 10th and 12th grades, perceived risk declined a year before use rose in the upturn of the 1990s, making perceived risk a leading indicator of change in use. (The same may have happened at 8th grade as well, but we lack data starting early enough to know.) The decline in perceived risk halted in 1996 in 8th and 10th grades; the increases in use ended a year or two later, again making perceived risk a leading indicator. From 1996 to 2000, perceived risk held fairly steady and the decline in use in the upper grades stalled. After some decline prior to 2002, perceived risk increased in all grades through 2004 as use decreased. Perceived risk fell after 2004 and 2005 in 8th and 12th grades respectively, (and since 2008 in 10th grade) presaging the more recent increase in use. In 2011 perceived risk continued to decline in grades 10 and 12 and leveled in grade 8."

"The apparent strength of these relationships in cross-sectional studies (e.g. Kandel, 1984) has been exaggerated because those adolescents who are most likely to use cannabis have lower academic aspirations and poorer high school performance prior to using cannabis than their peers who do not (Newcombe and Bentler, 1988). It remains possible that factors other than the marijuana use account for apparent causal relations. To the extent they may exist, these adverse effects of cannabis and other drug use upon development over and above the effect of pre-existing nonconformity may cascade throughout young adult life, affecting choice of occupation, level of income, choice of mate, and the quality of life of the user and his or her children."

"As with cannabis, alcohol use increased variability in lane position and headway (Casswell, 1979; Ramaekers et al., 2000; Smiley et al., 1981; Stein et al., 1983) but caused faster speeds (Casswell, 1977; Krueger & Vollrath, 2000; Peck et al., 1986; Smiley et al., 1987; Stein et al., 1983). Some studies also showed that alcohol use alone and in combination with cannabis affected visual search behavior (Lamers & Ramaekers, 2001; Moskowitz, Ziedman, & Sharma, 1976). Alcohol consumption combined with cannabis use also worsened driver performance relative to use of either substance alone. Lane position and headway variability were more exaggerated (Attwood et al., 1981; Ramaekers et al., 2000; Robbe, 1998) and speeds were faster (Peck et al., 1986).
"Both simulator and road studies showed that relative to alcohol use alone, participants who used cannabis alone or in combination with alcohol were more aware of their intoxication. Robbe (1998) found that participants who consumed 100 g/kg of cannabis rated their performance worse and the amount of effort required greater compared to those who consumed alcohol (0.05 BAC). Ramaekers et al. (2000) showed that cannabis use alone and in combination with alcohol consumption increased self-ratings of intoxication and decreased self-ratings of performance. Lamers and Ramaekers (2001) found that cannabis use alone (100 g/kg) and in combination with alcohol consumption resulted in lower ratings of alertness, greater perceptions of effort, and worse ratings of performance."

"Overall, 23,591 (90.9%) of the 25,951 drivers who died within 1 hour of a crash in these 6 states underwent toxicological testing. Drivers who were tested for drugs were similar in crash circumstances to those who were not tested, but they appeared to be slightly younger (mean age = 39.4 (standard deviation, 19.4) years vs. 43.4 (standard deviation, 27.7) years), more likely to be male (77.7% vs. 75.8%), more likely to be involved in nighttime crashes (51.4% vs. 47.0%), and more likely to have been involved in a crash in the previous 3 years (15.7% vs. 13.9%) than those who were not tested.
"Of the 23,591 drivers tested, 39.7% were positive for alcohol, and 24.8% tested positive for other drugs. The prevalence of alcohol involvement was stable at approximately 39% from 1999 to 2010 (Z = ?1.4, P = 0.16). Alcohol involvement was more prevalent in men (43.6%) than in women (26.1%), but trends were stable for both sexes (Table 1). In contrast, the prevalence of nonalcohol drugs showed a statistically significant increasing trend over the study period, rising from 16.6% (95% confidence interval (CI): 14.8, 18.4) in 1999 to 28.3% (95% CI: 26.0, 30.7) in 2010 (Z = ?10.19, P < 0.0001). The prevalence rates of non-alcohol drugs and 2 or more nonalcohol drugs increased significantly over the study period in both sexes (Table 1). The prevalence of nonalcohol drug use increased significantly across all age groups (Figure 1)."

"The prevalence of drugs detected in cases was higher than in controls across the drug categories (Table 3). Marijuana, narcotics, stimulants, and depressants were each associated with a significantly increased risk of fatal crash involvement, with estimated odds ratios ranging from 1.83 for marijuana to 4.83 for depressants (Table 3). Polydrug use, defined as use of two or more non-alcohol drugs, was associated with a 3.4-fold increased risk of fatal crash involvement (Table 3).
"About one-fifth (20.5%) of the cases tested positive for alcohol and one or more drugs, compared with 2.2% of the controls. Relative to drivers who tested positive for neither alcohol nor drugs, the estimated odds of fatal crash involvement increased over 13 folds for those who were alcohol-positive but drug-negative, more than two folds for those who were alcohol-negative but drug-positive, and 23 folds for those who were positive for both alcohol and drugs (Table 4)."

"We found only limited evidence to support the claim that cannabis use increases accident risk. Participants who had driven under the influence of cannabis in the previous year appeared to be no more likely than drug-free drivers to report that they had had an accident in the previous 12 months. Prima facie, this would seem to suggest that cannabis-intoxicated driving is not a risk factor for non-fatal accidents. In this sense, the results would support those of Longo et al. (2000b) who found no relationship between recent cannabis use and driver culpability for non-fatal accidents."

"A review of over a dozen of these [laboratory] experiments reveals three findings. First, after using marijuana, people drive more slowly. In addition, they increase the distance between their cars and the car in front of them. Third, they are less likely to attempt to pass other vehicles on the road. All of these practices can decrease the chance of crashes and certainly limit the probability of injury or death if an accident does occur. These three habits may explain the slightly lower risk of accidents that appears in the epidemiological studies. These results contrast dramatically to those found for alcohol. Alcohol intoxication often increases speed and passing while decreasing following distance, and markedly raises the chance of crashes.(632)"

"There is considerable evidence from laboratory studies that cannabis (marijuana) impairs reaction time, attention, tracking, hand-eye coordination, and concentration, although not all of these impairments were equally detected by all studies (Couper & Logan, 2004a; Heishman, Stitzer, & Yingling, 1989; Gieringer, 1988; Moskowitz, 1985). In reviewing the literature on marijuana, Smiley (1998) concluded that marijuana impairs performance in divided attention tasks (i.e., a poorer performance on subsidiary tasks). Jones et al. (2003) adds that Smiley’s finding is relevant to the multitasking essence of driving, in particular by making marijuana impaired drivers perhaps less able to handle unexpected events. Interestingly, there is also evidence showing that, unlike alcohol, marijuana enhances rather than mitigates the individual’s perception of impairment (Lamers & Ramaekers, 1999; Robbe & O'Hanlon, 1993; Perez-Reyes, Hicks, Bumberry, Jeffcoat, & Cook, 1988). Robbe and O'Hanlon (1993) reported that in laboratory conditions, drivers under the influence of marijuana were aware of their impairment, which led them to decrease speed, avoid passing other vehicles, and reduce other risk-taking behaviors. Such was not the case with alcohol; for the authors reported that alcohol-impaired drivers were generally not aware of impairment, and therefore did not adjust their driving accordingly."

"Participants receiving active marijuana decreased their speed more so than those receiving the placebo cigarette during a distracted section of the drive, An overall effect of marijuana was seen for the mean speed during the distracted driving (PASAT [Paced Auditory Serial-Addition Test] section), While no other changes in driving performance were found, marijuana appeared to hinder practice effects on the PASAT task, suggesting individuals may not be able to adequately use information and experience previously acquired while under the influence of marijuana, While only minimal differences in driving performance were found, this failure to benefit from prior practice may be detrimental to driving performance. Research has shown that graduated driver's licensing programs in which participants receive more on the road training results in a decrease in fatal crashes in 16-year-olds (Baker, Chen & Li 2006), If marijuana indeed impairs one's ability to use prior experience to improve performance, this will likely impair driving under pretrained conditions (e,g,, steering into a skid, allowing increased stopping time on slippery roads, etc)."

"The decreased speed during the simulated drive could be interpreted as an attempt to compensate for perceived cognitive impairment, Alternatively, marijuana may not have affected decision making and judgment and the reduction in speed would improve safety margins, While the clinical significance of a 3% to 5% decrease in speed may be questioned, previous research suggests such a decrease will result in approximately a 7% decrease in all injuries and a 15% decrease in fatalities (Nilsson 1981), Use of an alternate task design in which subjects are requested to drive as quickly and as safely as possible rather than following a posted speed limit may provide more insight into compensatory strategies employed while driving under the influence of marijuana, Use of a more challenging road paradigm (e.g., icy or gravel roads) which capitalizes on the use of practice effects may aid in identifying differences in driving performance under the influence of marijuana, There was significant between-subject variability in driving measures and future studies would be further strengthened by using a within-subjects design."

"When compared to alcohol, cannabis is detected far less often in accident-involved drivers. Drummer et al. (2003) cited several studies and found that alcohol was detected in 12.5% to 79% of drivers involved in accidents. With regard to crash risk, a large study conducted by Borkenstein, Crowther, Shumate, Zeil and Zylman (1964) compared BAC in approximately 6,000 accident-involved drivers and 7,600 nonaccident controls. They determined the crash risk for each BAC by comparing the number of accident-involved drivers with detected levels of alcohol at each BAC to the number of nonaccident control drivers with the same BAC. They found that crash risk increased sharply as BAC increased. More specifically, at a BAC of 0.10, drivers were approximately five times more likely to be involved in an accident.

"Similar crash risk results were obtained when data for culpable drivers were evaluated. Drummer (1995) found that drivers with detected levels of alcohol were 7.6 times more likely to be culpable. Longo et al. (2000) showed that drivers who tested positive for alcohol were 8.0 times more culpable, and alcohol consumption in combination with cannabis use produced an odds ratio of 5.4. Similar results were also noted by Swann (2000) and Drummer et al. (2003)."

"Most of the research on cannabis use has been conducted under laboratory conditions. The literature reviews by Robbe (1994), Hall, Solowij, and Lemon (1994), Border and Norton (1996), and Solowij (1998) agreed that the most extensive effect of cannabis is to impair memory and attention. Additional deficits include problems with temporal processing, (complex) reaction times, and dynamic tracking. These conclusions are generally consistent with the psychopharmacological effects of cannabis mentioned above, including problems with attention, memory, motor coordination, and alertness.
"A meta-analysis by Krüger and Berghaus (1995) profiled the effects of cannabis and alcohol. They reviewed 197 published studies of alcohol and 60 studies of cannabis. Their analysis showed that 50% of the reported effects were significant at a BAC of 0.073 g/dl and a THC level of 11 ng/ml. This implies that if the legal BAC threshold for alcohol is 0.08 g/dl, the corresponding level of THC that would impair the same percentage of tests would be approximately 11 ng/ml."

"Several studies have examined cannabis use in driving simulator and on-road situations. The most comprehensive review was done by Smiley in 1986 and then again in 1999. Several trends are evident and can be described by three general performance characteristics:

"1. Cannabis increased variability of speed and headway as well as lane position (Attwood, Williams, McBurney, & Frecker, 1981; Ramaekers, Robbe, & O'Hanlon, 2000; Robbe, 1998; Sexton et al., 2000; Smiley, Moskowitz, & Zeidman, 1981; Smiley, Noy, & Tostowaryk, 1987). This was more pronounced under high workload and unexpected conditions, such as curves and wind gusts.

"2. Cannabis increased the time needed to overtake another vehicle (Dott, 1972 [as cited in Smiley, 1986]) and delayed responses to both secondary and tracking tasks (Casswell, 1977; Moskowitz, Hulbert, & McGlothlin,
1976; Sexton et al., 2000; Smiley et al., 1981).

"3. Cannabis resulted in fewer attempts to overtake another vehicle(Dott, 1972) and larger distances required to pass (Ellingstad et al., 1973 [as cited in Smiley, 1986]). Evidence of increased caution also included slower speeds (Casswell, 1977; Hansteen, Miller, Lonero, Reid, & Jones, 1976; Krueger & Vollrath, 2000; Peck, Biasotti, Boland, Mallory, & Reeve, 1986; Sexton et al., 2000; Smiley et al., 1981; Stein, Allen, Cook, & Karl, 1983) and larger headways (Robbe, 1998; Smiley et al., 1987)."

"Based on the research to date, the harms associated with the actual use of cannabis likely pale in comparison with the widely observed harms attributable to cannabis prohibition. As such, policymakers should integrate the scientific research conducted on the likely impacts of current prohibitive approaches to cannabis use into the process of optimising cannabis policy."

"In 1937, Congress passed the first federal law to discourage cannabis production for marijuana while still permitting industrial uses of the crop (the Marihuana Tax Act; 50 Stat. 551). Under this statute, the government actively encouraged farmers to grow hemp for fiber and oil during World War II. After the war, competition from synthetic fibers, the Marihuana Tax Act, and increasing public anti-drug sentiment resulted in fewer and fewer acres of hemp being planted and none at all after 1958. The Controlled Substances Act of 1970 (CSA, 21 U.S.C. §801 et. seq.) placed the control of select plants, drugs, and chemical substances under federal jurisdiction and was enacted, in part, to replace previous federal drug laws with a single comprehensive statute.⁴³

"The CSA adopted the same definition of Cannabis sativa that appeared in the 1937 Marihuana Tax Act. The definition of “marihuana” (21 U.S.C. §802(16)) reads:

"The term marihuana means all parts of the plant Cannabis sativa L., whether growing or not; the seeds thereof; the resin extracted from any part of such plant; and every compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds or resin. Such term does not include the mature stalks of such plant, fiber produced from such stalks, oil or cake made from the seeds of such plant, any other compound ... or preparation of such mature stalks (except the resin extracted therefrom), fiber, oil, or cake, or the sterilized seed of such plant which is incapable of germination."

"The statute thus retains control over all varieties of the cannabis plant by virtue of including them under the term marihuana and does not distinguish between low- and high-THC varieties. The language exempts from control the parts of mature plants—stalks, fiber, oil, cake, etc.—intended for industrial uses. Some have argued that the CSA definition exempts industrial hemp under its term exclusions for stalks, fiber, oil, cake, and seeds.⁴⁴ DEA refutes this interpretation.⁴⁵

"Strictly speaking, CSA does not make growing cannabis illegal; rather, it places strict controls on its production, making it illegal to grow the crop without a DEA permit. Regarding industrial hemp, however, growers that comply with the 2014 farm bill provision (discussed in the next section) do not need DEA approval."

"There is no evidence that the depenalization component of the 1976 policy, per se, increased levels of cannabis use. On the other hand, the later growth in commercial access to cannabis, after de facto legalization, was accompanied by steep increases in use, even among youth. In interpreting that association, three points deserve emphasis. First, the association may not be causal; we have already seen that recent increases occurred in the United States and Oslo despite very different policies. Second, throughout most of the first two decades of the 1976 policy, Dutch use levels have remained at or below those in the United States. And third, it remains to be seen whether prevalence levels will drop again in response to the reduction to a 5-g limit, and to recent government efforts to close down coffee shops and more aggressively enforce the regulations."

"In California and Ohio, surveys before and after decriminalisation showed that cannabis use increased, but not at a greater rate than in US states which had not decriminalised cannabis. Single (1989) also reviewed data from two large US national surveys of drug use in the 1970s that compared rates of cannabis use in states which had and had not decriminalised cannabis. He found that the prevalence of cannabis use increased in all states, with a larger increase in those states which had not decriminalised (Single, 1989)."

"Our conclusion is that the present law on cannabis produces more harm than it prevents. It is very expensive of the time and resources of the criminal justice system and especially of the police. It inevitably bears more heavily on young people in the streets of inner cities, who are also more likely to be from minority ethnic communities, and as such is inimical to police-community relations. It criminalizes large numbers of otherwise law-abiding, mainly young, people to the detriment of their futures. It has become a proxy for the control of public order; and it inhibits accurate education about the relative risks of different drugs including the risks of cannabis itself."

"Rather than inducing violent or aggressive behavior through its purported effects of lowering inhibitions, weakening impulse control and heightening aggressive tendencies, marihuana was usually found to inhibit the expression of aggressive impulses by pacifying the user, interfering with muscular coordination, reducing psychomotor activities and generally producing states of drowsiness lethargy, timidity and passivity."

"Only orally given THC and, to a lesser extent, nefazodone have shown promise [in treating marijuana dependence]. THC reduced craving and ratings of anxiety, feelings of misery, difficulty sleeping, and chills (Haney et al., 2004). In addition, participants could not distinguish active THC from placebo. These findings were replicated in an outpatient study, which found that a moderate oral dosage of THC (10 mg, three times daily) suppressed many marijuana withdrawal symptoms and that a higher dosage (30 mg, three times daily) almost completely abolished withdrawal symptoms (Budney et al., 2007)."

"Under the current contract with the University of Mississippi for any given year NIDA [National Institute on Drug Abuse] has the option to grow either 1.5 or 6.5 acres of cannabis, or to not grow any at all, depending on research demand. Generally, 1.5 acres are grown in alternate years. The number of cannabis cigarettes produced from 1.5 acres is about 50,000-60,000, although it can be higher. Cigarettes are produced in three potencies: strength 1 - 3-4 %; strength 2 - 1.8-2.2 %; and strength 3 - placebo, as close to 0% as possible. During the past three years, the following quantities have been shipped: 1994 - 24,000 cigarettes; 1995 - 23, 100 - cigarettes; and 1996 17,700 cigarettes. Virtually all of the cigarettes shipped in the last three years have been for single patient INDs. As of March 1997 there were 278, 100 cigarettes in stock. The cigarettes are maintained in frozen storage and have a useful life of approximately five years."

"Increased funding for cannabis prohibition has increased cannabis seizures and arrests, but the assumption that this reduces cannabis potency, increases price or meaningfully reduces availability or use is inconsistent with surveillance data the US federal government has itself collected."

"There are indications that cannabis was used as early as 4000 B.C. in Central Asia and north-western China, with written evidence going back to 2700 B.C. in the pharmacopeia of emperor Chen-Nong. It then gradually spread across the globe, to India (some 1500 B.C., also mentioned in Altharva Veda, one of four holy books about 1400 B.C.¹), the Near and Middle East (some 900 B.C.), Europe (some 800 B.C.), various parts of South-East Asia (2nd century A.D.), Africa (as of the 11th century A.D.) to the Americas (19th century) and the rest of the world.²"