Recent trials add evidence for CBD antipsychotic potential, but are not yet sufficient for clinical recommendations
A review of recent CBD-schizophrenia trials found further evidence for CBD reducing positive symptoms, inconsistent effects on cognition, and good tolerability even at high doses.
Quick Facts
What This Study Found
Recent trials focused on sub-acute schizophrenia, clinical high-risk for psychosis (CHR-P), and frequent cannabis users. There is further evidence for CBD reducing positive symptoms but not negative symptoms. Cognitive effects were inconsistent, with one study reporting worsening. One study found CBD caused sedation, but others reported good tolerability at high doses. The authors emphasize that properly designed Phase III trials following regulatory guidelines are needed.
Key Numbers
CBD: further evidence for positive symptom reduction; no benefit for negative symptoms; inconsistent cognitive effects; one study reported worsening cognition; sedation in one study; good tolerability at high doses otherwise.
How They Did This
Narrative review of clinical trials published or initiated within the last 18 months investigating CBD for schizophrenia and related conditions.
Why This Research Matters
CBD antipsychotic potential has generated significant interest because current antipsychotics have severe side effects. This update provides the most current clinical trial landscape and identifies what is still missing.
The Bigger Picture
The specificity of CBD effects (positive symptoms yes, negative symptoms no, cognition unclear) is clinically important. It suggests CBD may work through a different mechanism than traditional antipsychotics, which is both its promise (novel target) and limitation (may not address the full syndrome).
What This Study Doesn't Tell Us
Narrative review (not systematic); limited number of trials to review; heterogeneous study designs; most trials small; the "further evidence" builds incrementally rather than providing definitive answers.
Questions This Raises
- ?Will CBD be effective as monotherapy or only as an adjunct?
- ?Which combinations of CBD with existing antipsychotics are safe and effective?
Trust & Context
- Key Stat:
- CBD: evidence for positive symptoms; not negative; cognition inconsistent
- Evidence Grade:
- Moderate: review of recent controlled trials, but trials are few and small.
- Study Age:
- Published 2020.
- Original Title:
- Cannabidiol as a treatment option for schizophrenia: recent evidence and current studies.
- Published In:
- Current opinion in psychiatry, 33(3), 185-191 (2020)
- Authors:
- Schoevers, Julie, Leweke, Judith E(2), Leweke, F Markus(6)
- Database ID:
- RTHC-02830
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Can CBD treat schizophrenia?
Recent trials add evidence that CBD may reduce positive symptoms (hallucinations, delusions) but does not appear to help negative symptoms (flat affect, social withdrawal). Cognition results are inconsistent. Properly designed Phase III trials are still needed.
Is CBD safe at high doses for psychosis?
Most recent studies report good tolerability even at high CBD doses, with one study noting sedation. This favorable side effect profile is a key advantage over traditional antipsychotics, which can cause weight gain, metabolic problems, and movement disorders.
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Cite This Study
https://rethinkthc.com/research/RTHC-02830APA
Schoevers, Julie; Leweke, Judith E; Leweke, F Markus. (2020). Cannabidiol as a treatment option for schizophrenia: recent evidence and current studies.. Current opinion in psychiatry, 33(3), 185-191. https://doi.org/10.1097/YCO.0000000000000596
MLA
Schoevers, Julie, et al. "Cannabidiol as a treatment option for schizophrenia: recent evidence and current studies.." Current opinion in psychiatry, 2020. https://doi.org/10.1097/YCO.0000000000000596
RethinkTHC
RethinkTHC Research Database. "Cannabidiol as a treatment option for schizophrenia: recent ..." RTHC-02830. Retrieved from https://rethinkthc.com/research/schoevers-2020-cannabidiol-as-a-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.