"Today, CBD is used for the treatment of a wide range of medical conditions. This started with the somewhat serendipitous discovery (by parents experimenting with self-medication for their children) that CBD had a therapeutic effect on a serious form of epilepsy in children, called Dravet syndrome [8]. This effect is now under clinical investigation with the pharmaceutical CBD product Epidiolex®, which is currently in phase 3 trials with encouraging results [9, 10].

"Numerous studies show the CBD immunomodulatory role in various diseases such as multiple sclerosis, arthritis, and diabetes. These animal and human ex vivo studies have been reviewed extensively elsewhere, but studies with pure CBD are still lacking. Often combinations of THC and CBD were used. It would be especially interesting to study when CBD is proinflammatory and under which circumstances it is anti-inflammatory and whether this leads to side effects (Burstein, 2015: Table 1 shows a summary of its anti-inflammatory actions; McAllister et al.

"There are various mechanisms underlying neuroprotection, for example, energy metabolism (whose alteration has been implied in several psychiatric disorders) and proper mitochondrial functioning.²⁴ An early study from 1976 found no side effects and no effect of 0.3–300 μg/mg protein CBD after 1 h of incubation on mitochondrial monoamine oxidase activity in porcine brains.²⁵ In hypoischemic newborn pigs, CBD elicited a neuroprotective effect, caused no side effects, and even led to beneficial effects on ventilatory, cardiac, and hemodynamic functions.²⁶

"CBD, which is nonhedonic, can reduce heroin-seeking behavior after, for example, cue-induced reinstatement. This was shown in an animal heroin self-administration study, where mice received 5 mg/kg CBD i.p. injections. The observed effect lasted for 2 weeks after CBD administration and could normalize the changes seen after stimulus cue-induced heroin seeking (expression of AMPA, GluR1, and CB1R). In addition, the described study was able to replicate previous findings showing no CBD side effects on locomotor behavior.²³"

"Various studies on CBD and psychosis have been conducted.²⁰ For instance, an animal model of psychosis can be created in mice by using the NMDAR antagonist MK-801. The behavioral changes (tested with the prepulse inhibition [PPI] test) were concomitant with decreased mRNA expression of the NMDAR GluN1 subunit gene (GRN1) in the hippocampus, decreased parvalbumin expression (=a calcium-binding protein expressed in a subclass of GABAergic interneurons), and higher FosB/ΔFosB expression (=markers for neuronal activity).

"Some studies indicate that under certain circumstances, CBD acute anxiolytic effects in rats were reversed after repeated 14-day administration of CBD.2 However, this finding might depend on the used animal model of anxiety or depression.

"Since several years, other pharmacologically relevant constituents of the Cannabis plant, apart from Δ9-THC, have come into the focus of research and legislation. The most prominent of those is cannabidiol (CBD). In contrast to Δ9-THC, it is nonintoxicating, but exerts a number of beneficial pharmacological effects. For instance, it is anxiolytic, anti-inflammatory, antiemetic, and antipsychotic.

"Cannabidiol (CBD) oil is essentially a concentrated solvent extract made from cannabis flowers or leaves that is dissolved in an edible oil such as sunflower, hemp, or olive oil. Solvents used can vary from relatively innocuous organic solvents (ethanol, isopropyl alcohol) to more harmful ones (petroleum-ether, naphtha), or even supercritical fluids (butane, CO2). The exact conditions and solvents applied have a great impact on, for example, the taste, color, and viscosity of the final product.

"We synthesised available evidence on the safety and efficacy of cannabinoids as an adjunctive treatment to conventional AEDs [Antiepileptic Drugs] in treating drug-resistant epilepsy. In many cases, there was qualitative evidence that cannabinoids reduced seizure frequency in some patients, improved other aspects of the patients’ quality of life and were generally well tolerated with mild-to-moderate AEs [Adverse Events].

"Recent developments suggest that non-psychotropic phytocannabinoids exert a wide range of pharmacological effects (Figure 1), many of which are of potential therapeutic interest. The most studied among these compounds is CBD, the pharmacological effects of which might be explained, at least in part, by a combination of mechanisms of action (Table 1, Figure 1). CBD has an extremely safe profile in humans, and it has been clinically evaluated (albeit in a preliminary fashion) for the treatment of anxiety, psychosis, and movement disorders.