In a small pilot RCT, smoked cannabis (high THC or high CBD) did not significantly reduce OCD symptoms compared to placebo in a controlled lab setting, though the study was underpowered.
OCD patients considering cannabis, psychiatrists, and mental health researchers.
Neither THC nor CBD significantly reduced OCD symptoms vs. placebo
What the researchers found
Fourteen adults with OCD underwent symptom provocation after smoking cannabis with high THC, high CBD, or placebo in a crossover design. Neither active condition significantly reduced obsessions or compulsions compared to placebo, though there were trends toward reduced anxiety with CBD.
Why it matters
Despite widespread anecdotal claims about cannabis helping OCD, this is one of the first controlled human lab studies to test it. The null findings are important for tempering expectations, though the small sample limits conclusions.
The numbers in context
14 participants; three conditions (high THC, high CBD, placebo) in crossover design; no statistically significant reduction in OCD symptoms with either active condition.
How the study worked
Double-blind, placebo-controlled, within-subjects crossover design. 14 adults with OCD smoked cannabis (high THC, high CBD, or placebo) before a symptom provocation task. OCD symptoms, anxiety, and distress were measured.
What this study cannot tell us
Very small sample (n=14); acute dosing only (one-time exposure cannot capture effects of sustained use); smoked cannabis makes precise dosing difficult; crossover design may have carryover effects.
How to read the evidence
Preliminary: very small sample (n=14), acute dosing only, pilot study.
When this study was published
Published 2020.
The bigger picture
Anecdotal reports of cannabis helping OCD symptoms are common, but controlled research tells a more nuanced story. This pilot suggests that acute cannabinoid exposure may not directly reduce core OCD symptoms, though larger studies are needed.
Questions still open
- Would longer-term CBD treatment show different results? Could specific cannabinoid doses or ratios be more effective for OCD?
Common questions
Did cannabis help OCD symptoms at all?
Why is this study important despite null results?
Read the original research
Acute effects of cannabinoids on symptoms of obsessive-compulsive disorder: A human laboratory study.
Depression and anxiety, 37(8), 801-811
Citation
Kayser, Reilly R; Haney, Margaret; Raskin, Marissa; Arout, Caroline; Simpson, Helen Blair. (2020). Acute effects of cannabinoids on symptoms of obsessive-compulsive disorder: A human laboratory study.. Depression and anxiety, 37(8), 801-811. https://doi.org/10.1002/da.23032
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