Researchers have found indications of high rates of cannabis use disorder among primary care patients in the state of Washington. Prevalence of Cannabis Use Disorder and Reasons for Use Among Adults in a US State Where Recreational Cannabis Use Is Legal was published at the journal JAMA Network Open on August 29, 2023.

"The study was conducted in Kaiser Permanente Washington, a large health system in Washington State where recreational cannabis use has been legal since 2012. Primary care patients who completed a confidential survey about cannabis use were included in the study. Survey design, sampling, procedures, weighting, and sample characterization, including comparison of respondents to eligible primary care sample and nonrespondents, have been reported previously.13 Briefly, 5000 patients 18 years and older were randomly selected from 108 950 eligible patients with electronic health record documentation of completing a cannabis screen as part of routine primary care from March 28, 2019, to September 12, 2019 (Figure). The single-item screen asks about the frequency of past-year cannabis use (ie, none, less than monthly, monthly, weekly, and daily).22"

The researchers found:

"Among patients who used cannabis, the prevalence of patient reasons for cannabis use included 42.4% (95% CI, 31.2%-54.3%) reporting medical use only, 25.1% (95% CI, 17.8%-34.2%) reporting nonmedical use only, and 32.5% (95% CI, 25.3%-40.8%) reporting both reasons for use. Patients reporting medical use only tended to be older (mean [SD] age, 53.6 [14.6] years), were mostly female (142 [76.5%]), retired (67 [33.6%]), and mostly had Medicare (84 [33.7%]). The prevalence of patients who reported any medical cannabis use (ie, medical use only or both reasons for use) was 74.7% (95% CI, 65.7%-82.1%), while the prevalence of any reported nonmedical cannabis use (ie, nonmedical use only or both reasons for use) was 57.5% (95% CI, 45.6%-68.6%).

"The prevalence of any CUD was 21.3% (95% CI, 15.4%-28.6%) and did not differ depending on patient reasons for use (Table 2). The prevalence of moderate to severe CUD was 6.5% (95% CI, 5.0%-8.6%) and differed across groups: 1.3% (95% CI, 0.0%-2.8%) for medical use only; 7.2% (95% CI, 3.9%-10.4%) for nonmedical use only; and 7.5% (95% CI, 5.7%-9.4%) both reasons for use (P = .01). For all groups, the most prevalent CUD symptoms were tolerance, uncontrolled escalation of use and craving. Compared with patients with medical use only, patients with nonmedical use only or both reasons for use were more likely to report withdrawal, use in hazardous situations, continue use despite consequences, time spent on use, interference with obligations, and activities given up.

"The most common primary mode of use was application for patients with medical use only, 36.1% (95% CI, 21.2%-51.0%), and inhalation for patients with nonmedical use only and both reasons for use, 59.5% (95% CI, 43.5%-75.6%) and 69.4% (95% CI, 60.4%-78.5%), respectively (Table 3). Patients who reported both reasons for use were more likely to use cannabis 3 or more times per day (95% CI, 39.7% vs 4.5%-14.0%), with 71.8% using cannabis 4 or more days per week (95% CI, 63.7%-79.9%). Post hoc sensitivity analyses to remove patients whose only mode of cannabis use was applied (n = 22) did not meaningfully impact the prevalence of any CUD or moderate to severe CUD, 25.0% (95% CI, 18.3%-33.0%) and 7.7% (95% CI, 5.9%-10.0%), respectively, or differences in prevalence by reason for use, and did not change results of significance testing (eTable 1 in Supplement 1)."