Systematic review finds limited evidence for CBD as an antipsychotic, but a favorable side effect profile

A systematic review of 8 studies involving 210 participants found limited evidence that CBD has antipsychotic effects and no evidence that it improves cognition or functioning, though it was well tolerated with fewer side effects than standard antipsychotics.

Ghabrash, Maykel Farag et al.·Psychiatry research·2020·Moderate EvidenceSystematic Review
RTHC-02569Systematic ReviewModerate Evidence2020RETHINKTHC RESEARCH DATABASErethinkthc.com/research

Quick Facts

Study Type
Systematic Review
Evidence
Moderate Evidence
Sample
Not reported

What This Study Found

CBD showed limited antipsychotic efficacy across studies, with no evidence supporting cognitive or functional benefits. However, CBD had a notably advantageous side effect profile compared to standard antipsychotics and was well tolerated across all studies.

Key Numbers

8 eligible studies, 210 total participants. Observational studies had higher risk of bias than experimental studies.

How They Did This

Systematic review searching CINAHL, EBM, EMBASE, MEDLINE, and PubMed from 1970 to 2019 for experimental and observational studies evaluating CBD's antipsychotic and cognitive properties in people with psychotic disorders.

Why This Research Matters

Current antipsychotics often have significant side effects that reduce adherence. If CBD could serve as an adjunctive treatment with fewer side effects, it might improve tolerability even if its direct antipsychotic effects are modest.

The Bigger Picture

The gap between CBD's favorable safety profile and its limited demonstrated efficacy highlights the need for larger, better-designed trials before CBD can be recommended as a psychosis treatment.

What This Study Doesn't Tell Us

Small total sample across studies. Heterogeneous study designs, dosing, and participant criteria make comparison difficult. Risk of bias was higher in observational studies.

Questions This Raises

  • ?Would higher CBD doses or longer treatment durations show stronger antipsychotic effects?
  • ?Is CBD more useful as an adjunct to existing antipsychotics rather than a standalone treatment?

Trust & Context

Key Stat:
8 studies, 210 participants: limited efficacy but favorable safety
Evidence Grade:
Moderate: systematic review methodology, but limited by small total sample and heterogeneous included studies.
Study Age:
Published in 2020 in Psychiatry Research.
Original Title:
Cannabidiol for the treatment of psychosis among patients with schizophrenia and other primary psychotic disorders: A systematic review with a risk of bias assessment.
Published In:
Psychiatry research, 286, 112890 (2020)
Database ID:
RTHC-02569

Evidence Hierarchy

Meta-Analysis / Systematic ReviewCombines many studies into one answer
This study
Randomized Controlled Trial
Cohort / Case-Control
Cross-Sectional / Observational
Case Report / Animal Study

Analyzes all available research on a topic using a structured method.

What do these levels mean? →

Frequently Asked Questions

Can CBD replace antipsychotic medications?

Based on current evidence, no. The review found limited evidence for antipsychotic efficacy. CBD's main advantage was fewer side effects, which might make it useful as an add-on treatment rather than a replacement.

Why were results so variable across studies?

Studies differed in CBD dosing, treatment duration, whether CBD was used alone or added to existing medications, and which patients were included. These differences make it hard to draw firm conclusions.

Read More on RethinkTHC

Cite This Study

RTHC-02569·https://rethinkthc.com/research/RTHC-02569

APA

Ghabrash, Maykel Farag; Coronado-Montoya, Stephanie; Aoun, John; Gagné, Andrée-Anne; Mansour, Flavi; Ouellet-Plamondon, Clairélaine; Trépanier, Annie; Jutras-Aswad, Didier. (2020). Cannabidiol for the treatment of psychosis among patients with schizophrenia and other primary psychotic disorders: A systematic review with a risk of bias assessment.. Psychiatry research, 286, 112890. https://doi.org/10.1016/j.psychres.2020.112890

MLA

Ghabrash, Maykel Farag, et al. "Cannabidiol for the treatment of psychosis among patients with schizophrenia and other primary psychotic disorders: A systematic review with a risk of bias assessment.." Psychiatry research, 2020. https://doi.org/10.1016/j.psychres.2020.112890

RethinkTHC

RethinkTHC Research Database. "Cannabidiol for the treatment of psychosis among patients wi..." RTHC-02569. Retrieved from https://rethinkthc.com/research/ghabrash-2020-cannabidiol-for-the-treatment

Access the Original Study

Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.

This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.