Vulnerability Factors for the Psychiatric and Behavioral Effects of Cannabis

Hypothesized pharmacogenomic and medication influences on tetrahydrocannabinol and cannabidiol metabolism in a cohort of unselected oral cannabis users

BACKGROUND

Differences in cannabinoid metabolism and patient responses can arise even with equivalent doses and formulations. Genetic polymorphisms in genes responsible for cannabinoid metabolism and medications that alter CYP450 pathways responsible for metabolism of cannabinoids may account for some of this variability.

MATERIALS AND METHODS

A retrospective chart review was conducted on a cohort of unselected patients who had previously completed pharmacogenomic testing and reported oral cannabis use, as defined as "oral" or "by mouth" route of administration. The objective was to identify atypical variants and medications in this cohort and formulate a hypothesis on how these variables influence the metabolism of Tetrahydrocannabinol (THC) and Cannabidiol (CBD).

RESULTS

Oral cannabis use was confirmed in 71 patients, with an average age of 68.5 years, and primarily white women. Of the 71 patients, 10 had no atypical variants; 31 had atypical variants in CYP2C9; 37 had atypical variants in CYP2C19; 6 had atypical variants in CYP3A4; and 15 had atypical variants in CYP3A5. Of the 71 patients, 5 were taking medications that could interact with THC, and 8 were taking medications that could interact with CBD.

CONCLUSION

The results this study reveal the spectrum of hypothesized alterations in THC and CBD metabolism due to atypical genetic variants and medications. The absence of published clinical outcomes in this field renders it challenging to estimate clinical significance of these findings. Until such data become available, clinicians should remain aware of the possibility that atypical variants and medications may impact patients' responses to THC and CBD.

An Individuality of Response to Cannabinoids: Challenges in Safety and Efficacy of Cannabis Products

Since legalization, cannabis/marijuana has been gaining considerable attention as a functional ingredient in food. ∆-9 tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids are key bioactive compounds with health benefits. The oral consumption of cannabis transports much less hazardous chemicals than smoking. Nevertheless, the response to cannabis is biphasically dose-dependent (hormesis; a low-dose stimulation and a high-dose inhibition) with wide individuality in responses. Thus, the exact same dose and preparation of cannabis may be beneficial for some but toxic to others. The purpose of this review is to highlight the concept of individual variations in response to cannabinoids, which leads to the challenge of establishing standard safe doses of cannabis products for the general population. The mechanisms of actions, acute and chronic toxicities, and factors affecting responses to cannabis products are updated. Based on the literature review, we found that the response to cannabis products depends on exposure factors (delivery route, duration, frequency, and interactions with food and drugs), individual factors (age, sex), and susceptibility factors (genetic polymorphisms of cannabinoid receptor gene, N-acylethanolamine-hydrolyzing enzymes, THC-metabolizing enzymes, and epigenetic regulations). Owing to the individuality of responses, the safest way to use cannabis-containing food products is to start low, go slow, and stay low.

THC Treatment Alters Glutamate Receptor Gene Expression in Human Stem Cell-Derived Neurons

Given the cognitive and behavioral effects following in utero Δ9-tetrahydrocannabinol (THC) exposure that have been reported in humans and rodents, it is critical to understand the precise consequences of THC on developing human neurons. Here, we utilize excitatory neurons derived from human-induced pluripotent stem cells (hiPSCs), and report that in vitro THC exposure reduced expression of glutamate receptor subunit genes (GRIA1, GRIA2, GRIN2A, and GRIN2B). By expanding these studies across hiPSC-derived neurons from individuals with a variety of genotypes, we believe that a hiPSC-based model will facilitate studies of the interaction of THC exposure and the genetic risk factors underlying neuropsychiatric disease vulnerability.

Long-term CB₁ receptor blockade enhances vulnerability to anxiogenic-like effects of cannabinoids

Compelling evidence has documented the anxiolytic and mood-enhancing properties of cannabis. In susceptible users, however, consumption of this drug is conducive to panic, paranoia and dysphoria. We hypothesized that the up-regulation of CB₁ receptors (CB₁Rs) in select brain regions may enhance the vulnerability to cannabinoid-induced anxiety. To test this possibility, we assessed the behavioral impact of a potent cannabinoid agonist (CP55,940; 0.05-0.1 mg/kg, IP) on C57BL/6 male mice, respectively subjected to a prolonged pre-treatment of either the selective CB₁R antagonist/inverse agonist AM251 (1 mg/kg/day IP, for 21 days, followed by a 3-day clearance period before testing) or its vehicle (VEH1). Anxiety-like responses were studied in the novel open field, elevated plus maze (EPM) and social interaction assays. While CP55,940 induced anxiolytic-like effects in the EPM in VEH1-exposed animals, it elicited opposite actions in AM251-exposed mice. In this last group, CP55,940 also reduced rearing and social interaction in comparison to its vehicle (VEH2). The divergent effects of CP55,940 in AM251- and VEH1-pretreated animals were confirmed in 129SvEv mice. Immunoblotting analyses on brain samples of C57BL/6 mice revealed that AM251 pre-treatment caused a significant up-regulation of CB₁R expression in the prefrontal cortex and striatum, but also a down-regulation of these receptors in the hippocampus and midbrain. Notably, CB₁R levels in the prefrontal cortex were negatively correlated with anxiolysis-related indices in the EPM; furthermore, midbrain CB₁R expression was positively correlated with the total duration of social interaction. These results suggest that regional variations in brain CB₁R expression may differentially condition the behavioral effects of cannabinoids with respect to anxiety-related responses.

Cannabinoid-related agents in the treatment of anxiety disorders: current knowledge and future perspectives

Rich evidence has shown that cannabis products exert a broad gamut of effects on emotional regulation. The main psychoactive ingredient of hemp, Δ9-tetrahydrocannabinol (THC), and its synthetic cannabinoid analogs have been reported to either attenuate or exacerbate anxiety and fear-related behaviors in humans and experimental animals. The heterogeneity of cannabis-induced psychological outcomes reflects a complex network of molecular interactions between the key neurobiological substrates of anxiety and fear and the endogenous cannabinoid system, mainly consisting of the arachidonic acid derivatives anandamide and 2-arachidonoylglycerol (2-AG) and two receptors, respectively termed CB1 and CB2. The high degree of interindividual variability in the responses to cannabis is contributed by a wide spectrum of factors, including genetic and environmental determinants, as well as differences in the relative concentrations of THC and other alkaloids (such as cannabidiol) within the plant itself. The present article reviews the currently available knowledge on the herbal, synthetic and endogenous cannabinoids with respect to the modulation of anxiety responses, and highlights the challenges that should be overcome to harness the therapeutic potential of some of these compounds, all the while limiting the side effects associated with cannabis consumption. In addition the article presents some promising patents on cannabinoid-related agents.