How does recent cannabis use affect symptoms in first-episode psychosis?
Among 247 first-episode psychosis patients, those who had used cannabis in the prior three months showed less anhedonia-asociality but more severe delusions and bizarre behavior, with no differences in cognitive functioning.
Quick Facts
What This Study Found
Cannabis users had significantly lower anhedonia-asociality scores (10.7 vs 12.1, p=0.023) but more severe delusions (19.3 vs 15.9, p=0.005) and bizarre behavior (p=0.01). No significant differences appeared across nine MATRICS cognitive battery measures. Cannabis dose did not correlate with any symptom or cognitive measure.
Key Numbers
247 patients; 6 psychiatric units; anhedonia-asociality: 10.7 vs 12.1 (p=0.023); delusions: 19.3 vs 15.9 (p=0.005); bizarre behavior significant (p=0.01); no differences across 9 MCCB cognitive measures; no dose-response relationship
How They Did This
Cross-sectional study of 247 first-episode psychosis patients from six inpatient psychiatric units (2008-2013). Cannabis use assessed via Longitudinal Substance Use Recall. Symptoms measured with SANS and SAPS. Cognition assessed with the MATRICS Consensus Cognitive Battery.
Why This Research Matters
The finding that cannabis use in psychosis is associated with less social withdrawal but more delusions suggests cannabis may have differential effects on different symptom dimensions, rather than making psychosis uniformly better or worse.
The Bigger Picture
The reduced anhedonia in cannabis users is intriguing. It could mean cannabis helps with social withdrawal, or that people with less anhedonia are more likely to seek out cannabis. Either way, the pattern suggests cannabis users with psychosis may represent a distinct clinical subgroup.
What This Study Doesn't Tell Us
Cross-sectional; cannot determine if cannabis caused symptom differences or if pre-existing symptom profiles influenced cannabis use. Hospital-based sample during acute episodes. Self-reported cannabis use.
Questions This Raises
- ?Does cannabis genuinely reduce anhedonia in psychosis, or do less anhedonic patients simply use more cannabis?
- ?Would targeting cannabis use in this population worsen negative symptoms?
- ?Could this symptom profile distinguish cannabis-related from non-cannabis psychosis?
Trust & Context
- Key Stat:
- Less anhedonia, more delusions
- Evidence Grade:
- Moderately large clinical sample with validated measures, but cross-sectional design limits causal inference.
- Study Age:
- Published in 2021 with data from 2008-2013; cannabis potency has increased since.
- Original Title:
- Symptomatology and neurocognition among first-episode psychosis patients with and without cannabis use in the three months prior to first hospitalization.
- Published In:
- Schizophrenia research, 228, 83-88 (2021)
- Authors:
- Pope, Leah G, Manseau, Marc W, Kelley, Mary E(4), Compton, Michael T
- Database ID:
- RTHC-03435
Evidence Hierarchy
A snapshot of a population at one point in time.
What do these levels mean? →Frequently Asked Questions
Does cannabis make psychosis better or worse?
Neither simply. This study found cannabis users had less social withdrawal (a positive sign) but more severe delusions and bizarre behavior. The effects appear to differ across symptom types rather than being uniformly harmful or helpful.
Does cannabis affect thinking ability in psychosis?
No differences were found across nine cognitive measures between cannabis-using and non-using psychosis patients, suggesting cannabis did not add to the cognitive deficits already present in psychosis.
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Cite This Study
https://rethinkthc.com/research/RTHC-03435APA
Pope, Leah G; Manseau, Marc W; Kelley, Mary E; Compton, Michael T. (2021). Symptomatology and neurocognition among first-episode psychosis patients with and without cannabis use in the three months prior to first hospitalization.. Schizophrenia research, 228, 83-88. https://doi.org/10.1016/j.schres.2020.12.012
MLA
Pope, Leah G, et al. "Symptomatology and neurocognition among first-episode psychosis patients with and without cannabis use in the three months prior to first hospitalization.." Schizophrenia research, 2021. https://doi.org/10.1016/j.schres.2020.12.012
RethinkTHC
RethinkTHC Research Database. "Symptomatology and neurocognition among first-episode psycho..." RTHC-03435. Retrieved from https://rethinkthc.com/research/pope-2021-symptomatology-and-neurocognition-among
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.