Evidence map›Paper›PMID 20660494›Full record

SynthesisSchizophrenia bulletin2012

The impact of cannabis use on cognitive functioning in patients with schizophrenia: a meta-analysis of existing findings and new data in a first-episode sample.

Murat Yücel, Emre Bora, Dan I Lubman, Nadia Solowij, Warrick J Brewer, Sue M Cotton, Philippe Conus, Michael J Takagi, Alex Fornito, Stephen J Wood and 2 more

Abstract readMeta-Analysis
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Schizophrenia bulletin, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 91 papers, 5 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
91citing papers in PubMed, 5 pooled it
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

91 citing papers in PubMed, 5 syntheses or guidelines pooled it.

  1. Cognitive impairment in people with schizophrenia: an umbrella review.European archives of psychiatry and clinical neuroscience · 2022
    Pooled it
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  6. Trial
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  10. Article
  11. Novel neurotherapeutic targets for substance use disorders: Neuroplasticity, neuroinflammation, gasotransmitters and non-canonical organ systems.Neurotherapeutics : the journal of the American Society for Experimental NeuroTherapeutics · 2025
    Review
  12. Article
  13. Article
  14. The relationship between substance use and self-reported aspects of social functioning in patients with a psychotic disorder.European psychiatry : the journal of the Association of European Psychiatrists · 2024
    Article
  15. Review
  16. Article
  17. Article
  18. Nerve Growth Factor in Psychiatric Disorders: A Scoping Review.Indian journal of psychological medicine · 2023
    Article
  19. Review
  20. Article

31 more citing papers are in PubMed but not listed here.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors.

Murat YücelMelbourne Neuropsychiatry Centre, Department of Psychiatry, University of Melbourne and Melbourne Health, National Neuroscience Facility, Alan Gilbert Building, 161 Barry Street, Carlton South, Victoria 3053, Australia. murat@unimelb.edu.au
Emre Bora
Dan I Lubman
Nadia Solowij
Warrick J Brewer
Sue M Cotton
Philippe Conus
Michael J Takagi
Alex Fornito
Stephen J Wood
Patrick D McGorry
Christos Pantelis

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

Cannabis use is highly prevalent among people with schizophrenia, and coupled with impaired cognition, is thought to heighten the risk of illness onset. However, while heavy cannabis use has been associated with cognitive deficits in long-term users, studies among patients with schizophrenia have been contradictory. This article consists of 2 studies. In Study I, a meta-analysis of 10 studies comprising 572 patients with established schizophrenia (with and without comorbid cannabis use) was conducted. Patients with a history of cannabis use were found to have superior neuropsychological functioning. This finding was largely driven by studies that included patients with a lifetime history of cannabis use rather than current or recent use. In Study II, we examined the neuropsychological performance of 85 patients with first-episode psychosis (FEP) and 43 healthy nonusing controls. Relative to controls, FEP patients with a history of cannabis use (FEP + CANN; n = 59) displayed only selective neuropsychological impairments while those without a history (FEP - CANN; n = 26) displayed generalized deficits. When directly compared, FEP + CANN patients performed better on tests of visual memory, working memory, and executive functioning. Patients with early onset cannabis use had less neuropsychological impairment than patients with later onset use. Together, these findings suggest that patients with schizophrenia or FEP with a history of cannabis use have superior neuropsychological functioning compared with nonusing patients. This association between better cognitive performance and cannabis use in schizophrenia may be driven by a subgroup of "neurocognitively less impaired" patients, who only developed psychosis after a relatively early initiation into cannabis use.

Indexed as

Marijuana AbuseAdolescentAdultCannabinoidsCase-Control StudiesCognitionExecutive FunctionFemaleHumansMaleMemoryMemory, Short-TermNeuropsychological TestsSchizophreniaCannabinoids

Identifiers

PMID20660494
PMCPMC3283159

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.