Medical Cannabis and Mental Health: UK Psychiatry Review

The Royal College of Psychiatrists has published a commissioned systematic review examining the clinical evidence for cannabis-based medicinal products (CBMPs) in the treatment of anxiety disorders, post-traumatic stress disorder, and treatment-resistant depression. The review analysed 47 controlled studies and 12 open-label registry datasets with a combined participant count exceeding 18,000.

Key Findings by Condition

The review found the strongest evidence for CBMP use in PTSD-associated hyperarousal symptoms, where THC-dominant products demonstrated significant reductions in nightmare frequency and sleep disruption in three separate randomised controlled trials. Evidence for generalised anxiety disorder was rated as moderate, with CBD-dominant formulations showing the most favourable benefit-to-risk profile.

Areas of Caution

• High-THC products showed mixed results in anxiety disorders, with some trials reporting worsening symptoms at higher doses
• Evidence for treatment-resistant depression remains preliminary; no UK-specific trial data currently exists
• The review identified a significant gap in long-term safety data beyond 12 months for psychiatric indications
• Interactions with common antidepressant and antipsychotic medications require further investigation

Prescribing Recommendations

The College stopped short of issuing a formal endorsement of CBMPs for psychiatric conditions but acknowledged that, under specialist supervision, certain patients with PTSD may derive meaningful clinical benefit. The review recommended that any prescribing for mental health indications occur within a structured monitoring framework with access to psychological support.

"The evidence does not support blanket rejection, nor does it support blanket adoption. What it supports is careful, individualised clinical decision-making."