Schizophrenia patients who used cannabis actually had better cognitive function than non-users
Among 104 first-episode psychosis patients, cannabis users showed better attention and executive function than non-users at baseline and after one year, suggesting they may represent a cognitively higher-functioning subgroup.
Quick Facts
What This Study Found
Researchers compared cognitive functioning between cannabis-using and non-using patients with first-episode schizophrenia. The results contradicted expectations.
Cannabis-using patients (47 users) performed better on attention and executive function tests than non-users (57 non-users) both at initial assessment and after one year of treatment. Both groups improved similarly over the follow-up period.
Cannabis users also had better social premorbid adjustment, particularly during early life stages. The amount of cannabis consumed and duration of use did not correlate with cognitive performance.
The authors concluded that cannabis-using schizophrenia patients may represent a distinct subgroup with better baseline cognitive abilities and social functioning prior to illness onset.
Key Numbers
104 patients (47 cannabis users, 57 non-users) and 37 healthy controls. Cannabis users performed better on attention and executive function at baseline and 1-year follow-up. Amount and duration of cannabis use did not predict cognitive performance.
How They Did This
Longitudinal study of 104 first-episode non-affective psychosis patients (47 cannabis users, 57 non-users) and 37 healthy controls. Cross-sectional and one-year longitudinal cognitive assessments with clinical and premorbid adjustment measures.
Why This Research Matters
The finding challenged the assumption that cannabis always worsens cognitive outcomes in schizophrenia, suggesting instead that cannabis-using patients may have had better functioning to begin with.
The Bigger Picture
This study contributed to a growing body of research suggesting that the relationship between cannabis and psychosis is more complex than simple harm, with cannabis-using patients potentially representing a distinct clinical subgroup.
What This Study Doesn't Tell Us
Observational design cannot determine causation. Better cognition in users may reflect selection effects (higher-functioning people being more socially engaged and thus more exposed to cannabis). Cannabis use was assessed prior to illness onset only.
Questions This Raises
- ?Do people with better cognitive function seek out cannabis more, or does cannabis use select for a different pathway to psychosis?
- ?How should treatment differ for these subgroups?
Trust & Context
- Key Stat:
- Cannabis-using psychosis patients had better attention and executive function
- Evidence Grade:
- Longitudinal study with one-year follow-up and healthy control group, but observational design limits causal conclusions.
- Study Age:
- Published in 2010. The "paradox" of better cognition in cannabis-using psychosis patients has continued to be studied.
- Original Title:
- Cannabis use and cognitive functioning in first-episode schizophrenia patients.
- Published In:
- Schizophrenia research, 124(1-3), 142-51 (2010)
- Authors:
- Rodríguez-Sánchez, José Manuel, Ayesa-Arriola, Rosa(3), Mata, Ignacio(2), Moreno-Calle, Teresa, Perez-Iglesias, Rocío, González-Blanch, César, Periañez, José Antonio, Vazquez-Barquero, José Luis, Crespo-Facorro, Benedicto
- Database ID:
- RTHC-00450
Evidence Hierarchy
Follows a group of people over time to track how outcomes develop.
What do these levels mean? →Frequently Asked Questions
Does cannabis improve cognition in people with schizophrenia?
This study did not show cannabis improved cognition. Rather, patients who happened to use cannabis already had better cognitive abilities and social functioning before their illness, suggesting they represent a distinct subgroup.
Why would cannabis users have better cognitive function?
The authors proposed that cannabis-using patients may have a different pathway to psychosis, starting from a higher baseline of social and cognitive functioning. Using cannabis requires social engagement that may be associated with better premorbid adjustment.
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Cite This Study
https://rethinkthc.com/research/RTHC-00450APA
Rodríguez-Sánchez, José Manuel; Ayesa-Arriola, Rosa; Mata, Ignacio; Moreno-Calle, Teresa; Perez-Iglesias, Rocío; González-Blanch, César; Periañez, José Antonio; Vazquez-Barquero, José Luis; Crespo-Facorro, Benedicto. (2010). Cannabis use and cognitive functioning in first-episode schizophrenia patients.. Schizophrenia research, 124(1-3), 142-51. https://doi.org/10.1016/j.schres.2010.08.017
MLA
Rodríguez-Sánchez, José Manuel, et al. "Cannabis use and cognitive functioning in first-episode schizophrenia patients.." Schizophrenia research, 2010. https://doi.org/10.1016/j.schres.2010.08.017
RethinkTHC
RethinkTHC Research Database. "Cannabis use and cognitive functioning in first-episode schi..." RTHC-00450. Retrieved from https://rethinkthc.com/research/rodriguez-sanchez-2010-cannabis-use-and-cognitive
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.