Acute effects of cannabinoids on symptoms of obsessive-compulsive disorder: A human laboratory study.

In adults with obsessive-compulsive disorder (OCD), smoked cannabis containing primarily THC or CBD had little acute effect on OCD symptoms and produced smaller reductions in anxiety than placebo. In a randomized, placebo-controlled, within-subjects laboratory study, 12 participants completed three sessions smoking placebo (0% THC/0% CBD), THC (7.0% THC/0.18% CBD), or CBD (0.4% THC/10.4% CBD). Self-reported OCD symptoms and anxiety decreased over time in all conditions, but OCD symptoms did not differ by cannabis varietal. State anxiety was significantly lower immediately after placebo than after either active cannabis. THC increased heart rate, blood pressure, and intoxication relative to placebo and CBD.

Study at a glance

Abstract

Preclinical data implicate the endocannabinoid system in the pathology underlying obsessive-compulsive disorder (OCD), while survey data have linked OCD symptoms to increased cannabis use. Cannabis products are increasingly marketed as treatments for anxiety and other OCD-related symptoms. Yet, few studies have tested the acute effects of cannabis on psychiatric symptoms in humans. We recruited 14 adults with OCD and prior experience using cannabis to enter a randomized, placebo-controlled, human laboratory study to compare the effects on OCD symptoms of cannabis containing varying concentrations of Δ-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) on OCD symptoms to placebo. We used a within-subjects design to increase statistical power. Across three laboratory sessions, participants smoked three cannabis varietals in random order: placebo (0% THC/0% CBD); THC (7.0% THC/0.18% CBD); and CBD (0.4% THC/10.4% CBD). We analyzed acute changes in OCD symptoms, state anxiety, cardiovascular measures, and drug-related effects (e.g., euphoria) as a function of varietal. Twelve participants completed the study. THC increased heart rate, blood pressure, and intoxication compared with CBD and placebo. Self-reported OCD symptoms and anxiety decreased over time in all three conditions. Although OCD symptoms did not vary as a function of cannabis varietal, state anxiety was significantly lower immediately after placebo administration relative to both THC and CBD. This is the first placebo-controlled investigation of cannabis in adults with OCD. The data suggest that smoked cannabis, whether containing primarily THC or CBD, has little acute impact on OCD symptoms and yields smaller reductions in anxiety compared to placebo.