What topics does this cannabis study cover?

This study covers research on: THC, Anxiety, Mental Health, Addiction.

Where was this research published?

Published in Psychiatry research on August 11, 2026.

Cannabinoids show limited promise, but major safety gaps remain

Q: What did this research study find?

Randomized trials found a **modest reduction in *anxiety symptoms***, but the evidence had high variability and was rated as low certainty.

Cannabis and cannabinoids for the treatment of mental and substance use disorders and symptoms: A systematic review and meta-analysis of experimental and observational studies.

Psychiatry research • August 11, 2026 • Highly Relevant

🤖

AI Summary

This systematic review examined whether cannabis and cannabinoids can treat mental health and substance use disorders. It included 82 experimental studies and 118 observational studies. Randomized trials found a modest reduction in anxiety symptoms and a possible improvement in PTSD symptoms in one small trial, but the evidence was limited and often indirect. There was no clear benefit for depression, ADHD, psychosis, or Tourette syndrome.

For substance use disorders, one randomized trial found that cannabinoids worsened cannabis use disorder severity, while evidence for alcohol, opioid, and tobacco use disorders was very limited. Observational studies often suggested benefits, but their results were considered unreliable because of a high risk of bias. THC was linked to more withdrawals due to adverse events, and the overall certainty of evidence was predominantly very low. For practical purposes, the findings do not support cannabinoids as first-line treatments, and users should be especially cautious about THC when managing mental health or substance use problems.

💡 Key Findings

Randomized trials found a modest reduction in anxiety symptoms, but the evidence had high variability and was rated as low certainty.

Good

65%

A single small trial suggested a large improvement in PTSD symptoms, but this result is too limited to establish effectiveness.

Moderate

45%

There was no clear benefit for depression, ADHD, psychosis, or Tourette syndrome in the randomized evidence.

Good

75%

In one trial, cannabinoids worsened cannabis use disorder severity, while evidence for other substance use disorders was very limited.

Good

70%

THC was associated with more withdrawals due to adverse events, reinforcing the need for caution and monitoring.

High

80%

📄 Original Abstract

Interest in cannabinoids for mental and substance use disorders is increasing. We examined experimental and observational evidence for treating these disorders and their symptoms. Systematic review and meta-analysis (PROSPERO CRD42023467536). We searched CENTRAL, MEDLINE, Embase and PsycINFO to May 2025 for studies of cannabinoids in adults (≥18 years) with ADHD, anxiety, depression, PTSD, psychosis or Tourette syndrome, or alcohol, cannabis, opioid or tobacco use disorders. Two reviewers screened, extracted and assessed quality using a risk-of-bias tool and GRADE. We included 82 experimental and 118 observational studies. In RCTs, cannabinoids reduced anxiety symptoms (SMD=-0.40; 95% CI: -0.57, -0.23; I²=90%) and, in one small trial, PTSD symptoms (SMD=-2.60; 95% CI: -4.58, -0.62; n=20), with trivial-to-no effect on depression (SMD=-0.20; 95% CI: -0.43, 0.04; I²=91.6%), ADHD, psychosis and Tourette syndrome. Much anxiety and depression evidence came from symptoms measured as secondary outcomes in other primary conditions. Cannabinoids worsened cannabis use disorder severity in one RCT (SMD=2.35; 95% CI: 1.49, 3.21), with no effect on craving or withdrawal; evidence for alcohol, opioid and tobacco use disorders was very limited. Observational studies suggested improvements but had high risk of bias. The only significant safety finding was increased withdrawals due to adverse events with THC (OR=2.78; 95% CI: 1.66, 4.65). Certainty was predominantly very low. The evidence base shows very low certainty, high heterogeneity and methodological limitations, and is insufficient to support cannabinoids as first-line treatment. Signals for anxiety and PTSD are limited by indirectness and low certainty; no benefit was evident for depression; THC-related safety signals warrant careful consideration.

Paper Type

📄 Research

Publication

Journal: Psychiatry research
Published: August 11, 2026
PMID: 42617303
DOI: 10.1016/j.psychres.2026.117380

Authors (11)

Chrianna Bharat National Drug and Alcohol Research Centre, UNSW Sydney, Randwick, Australia; School of Population and Global Health, University of Western Australia, Perth, Australia. Electronic address: c.bharat@unsw.edu.au.
Xintong Huang National Drug and Alcohol Research Centre, UNSW Sydney, Randwick, Australia.
Gabrielle Campbell National Drug and Alcohol Research Centre, UNSW Sydney, Randwick, Australia; National Centre for Youth Substance Use Research (NCYSUR), School of Psychology, University of Queensland, Brisbane, Australia.
Calvert Tisdale National Drug and Alcohol Research Centre, UNSW Sydney, Randwick, Australia; Monash Addiction Research Centre, Eastern Health Clinical School, Monash University, Melbourne, Australia.
Sophia Glasgow National Centre for Youth Substance Use Research (NCYSUR), School of Psychology, University of Queensland, Brisbane, Australia.
+6 more authors