Effects of Marijuana on Symptoms of OCD (ECOS)

The purpose of this pilot research study is to test whether certain components of the marijuana plant, known as "cannabinoids", may help to reduce symptoms in patients with OCD. Specifically, patients enrolled in the study will smoke marijuana containing different concentrations of 2 different cannabinoids, THC and CBD. Both of these agents act on the brain's "endocannabinoid system," which has been hypothesized to play a role in OCD. Neither compound is currently FDA-approved for treating OCD.

Prior research suggests that certain areas of the brain are receptive to chemicals like those found in the cannabis (marijuana) plant, known as cannabinoids, and that these regions may be involved in anxiety disorders and OCD. More recent data shows that synthetic drugs that target these systems may be helpful in conditions related to OCD like anxiety disorders and Tourette's syndrome. Thus, these substances could also possibly be useful to treat OCD symptoms. However, to date there has been little research regarding the role of cannabinoids in OCD. The purpose of this study is to examine the effects of different cannabinoids on OCD symptoms in humans. To accomplish this in a laboratory setting, patients with OCD who are also occasional cannabis users will receive different combinations of two of the most well-studied cannabinoids, delta-9-tetrahydrocannabinol (THC, the main psychoactive component in cannabis) and cannabidiol (CBD, another component of the cannabis plant). We will then measure acute effects on OCD symptoms, anxiety, intoxication, and cardiovascular outcomes (i.e. blood pressure and heart rate).

This condition involves the ingestion of marijuana with a high THC (5-10%) and low CBD (<1%) content.

THC and CBD are "cannabinoids" which are found naturally in the marijuana plant. Both act on the brain's "endocannabinoid system," which has been hypothesized to play a role in OCD.

An adapted version of the Yale-Brown Obsessive-Compulsive Scale (YBOCS) which measures change in OCD symptoms over short time frames (i.e., since the last assessment as opposed to over the past week). Total score is reported. Scores range from 0 (no symptoms) to 40 (severe symptoms).

Baseline was obtained at the beginning of each session. Then, change from baseline was measured following cannabis administration (minute 0) at minutes 20, 40, 60, 90, 120, and 180. This procedure was repeated for each of the 3 conditions.

A scale measuring state (acute) anxiety. Total score is reported. Scores range from 20 (no state anxiety) to 80 (severe state anxiety).

Baseline obtained at the beginning of the session (Minutes 0), and then the scale was obtained at minutes 20, 40, 60, 90, 120, and 180 after cannabis administration.

Inclusion Criteria: Age 21-55 Physically healthy Diagnosed with OCD Current marijuana user Women of childbearing potential must be using an effective form of birth control Not currently taking psychotropic medications Ability to provide informed consent Exclusion Criteria: History of any significant medical condition that may increase the risk of participation Females who are pregnant or nursing If female, not pregnant Current or lifetime history of psychiatric disorders other than OCD that may increase the risk of participation Current substance use disorder Severe depression or positive urine toxicology (other than THC) at screening, or any adverse reaction to a cannabinoid Patients who are seeking treatment for substance abuse Patients who are planning to begin a course of cognitive-behavioral therapy within 8 weeks of beginning the study