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Study register · detail Meta-Analyse (Bayesian Model-Averaged) · Psychosis · 2025

The association between cannabis use and paranoia: Meta-analysis of experimental and observational studies

Belvederi Murri et al. ·Neuroscience & Biobehavioral Reviews Impact 7.2
Clear benefit GRADE High 3 citations
Samplek = 13 Studien
n = 13.559 Pat.
ControlPlacebo / Non-users
EndpointParanoid symptoms
Blindingunklar
DesignMeta-Analyse (Bayesian Model-Averaged)
Key finding

Cannabinoids are associated with significantly increased paranoid symptoms, with consistent effects in experimental and population-based studies.

Summary

Bayesian meta-analysis across k=13 studies (n=13.559) on cannabis and paranoid symptoms; experimental studies (k=5): cannabinoid participants developed more severe paranoid symptoms than placebo (SMD=0.47, 95% CI 0.13–0.48, PPI=94%); cross-sectional studies (k=4): cannabis users higher odds for paranoia (OR=1.75, 95% CI 1.43–2.07, PPI=99%); prospective studies (k=3) show association with later paranoia onset.

P
PopulationAdults from general population, clinical populations and experimental samples; pooled n=13.559
I
InterventionCannabinoids (THC-prevalent, THC-CBD-mixed, CBD-prevalent; experimental and observational)
C
ControlPlacebo (experimental studies) / Non-users (observational studies)
O
OutcomeExperimental: SMD=0,47 (95% CI 0,13–0,48, PPI 94%) for stronger paranoid symptoms under cannabinoids vs. placebo; cross-sectional: OR=1,75 (95% CI 1,43–2,07, PPI 99%) for paranoid symptoms in users vs. non-users; prospective studies confirm temporal association
Confidence in the evidence
High

The highest of four GRADE levels, the effect estimate is very reliable.

Quality profile
Sample size ★★★★★
Blinding —
Effect size Clear benefit
Citations / year ★★★★★
Authors
Belvederi Murri M, Catania S, Centra S, Folesani F, Muscettola A, Zerbinati L, Toffanin T, Ferrara M, Ossola P, Rossi R, Jannini T, Caruso R, Nanni MG, Grassi L
DOI 10.1016/j.neubiorev.2025.106269↗
Design: Meta-Analyse (Bayesian Model-Averaged)
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Indication
Further studies on Psychosis
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The impediment to action advances action. — Marcus Aurelius