Comprehensive Review Finds Cannabis-Using Psychosis Patients May Be Neurobiologically Different

What the researchers found

Cannabis use is associated with increased risk of developing psychotic disorders, increased hospitalization, longer hospital stays, and treatment failure. The systematic review of 70 studies (3,000+ patients) found evidence for distinct neurobiological patterns in cannabis-using versus non-using psychosis patients, though the biological underpinnings remain to be fully elucidated.

Why it matters

If cannabis-using psychosis patients truly represent a neurobiologically distinct subgroup, they may need different treatment approaches. Understanding these differences could lead to more personalized interventions.

The numbers in context

70 studies reviewed, over 3,000 patients included. Evidence covers risk of developing psychosis, hospitalization patterns, and treatment response in cannabis-using versus non-using patients.

How the study worked

Two-part approach: summary of longitudinal evidence on cannabis-psychosis associations, plus systematic review of 70 studies examining neurobiological and neurochemical mechanisms in over 3,000 patients with psychotic disorders or at increased risk.

What this study cannot tell us

Many included studies were cross-sectional. Establishing causation from observational data is inherently limited. Heterogeneity in cannabis use patterns and psychosis definitions across studies.

How to read the evidence

Strong - large systematic review of 70 studies with over 3,000 patients, though individual study quality varied.

When this study was published

Published in 2018.

The bigger picture

This review makes the case that cannabis is not just a confounding variable in psychosis research but a significant factor that may create distinct clinical and neurobiological profiles. This has implications for both prevention and treatment strategies.

Questions still open

• Should cannabis-using psychosis patients receive different treatments? Could neurobiological markers identify who is most vulnerable to cannabis-related psychosis? What role does THC potency play in these neurobiological differences?

Common questions

Read the original research

Are cannabis-using and non-using patients different groups? Towards understanding the neurobiology of cannabis use in psychotic disorders.

Journal of psychopharmacology (Oxford, England), 32(8), 825-849

Citation

Sami, Musa Basseer; Bhattacharyya, Sagnik. (2018). Are cannabis-using and non-using patients different groups? Towards understanding the neurobiology of cannabis use in psychotic disorders.. Journal of psychopharmacology (Oxford, England), 32(8), 825-849. https://doi.org/10.1177/0269881118760662

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