Evidence map›Paper›PMID 26884547›Full record

SynthesisSchizophrenia bulletin2016

Meta-analysis of the Association Between the Level of Cannabis Use and Risk of Psychosis.

Arianna Marconi, Marta Di Forti, Cathryn M Lewis, Robin M Murray, Evangelos Vassos

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

Synthesis in Schizophrenia bulletin, 2016. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 344 papers, 8 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
344citing papers in PubMed, 8 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

344 citing papers in PubMed, 8 syntheses or guidelines pooled it.

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  18. An etiological approach to psychosis: potential benefits for treatment, research and prevention.World psychiatry : official journal of the World Psychiatric Association (WPA) · 2026
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284 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

5 authors.

Arianna MarconiDepartment of Psychosis Studies, King's College London, Institute of Psychiatry Psychology & Neuroscience, London, UK;
Marta Di FortiDepartment of Psychosis Studies, King's College London, Institute of Psychiatry Psychology & Neuroscience, London, UK;
Cathryn M LewisKing's College London, Institute of Psychiatry Psychology & Neuroscience, MRC SGDP Centre, London, UK.
Robin M MurrayDepartment of Psychosis Studies, King's College London, Institute of Psychiatry Psychology & Neuroscience, London, UK;
Evangelos VassosKing's College London, Institute of Psychiatry Psychology & Neuroscience, MRC SGDP Centre, London, UK evangelos.vassos@kcl.ac.uk.

Funding

Department of Health RP-PG-0606-1049Medical Research Council G0600972Medical Research Council G0700995Medical Research Council G1100583Medical Research Council MR/K004867/1Medical Research Council MR/K013807/1Medical Research Council MR/M008436/1
6 · The paper itself

Abstract

Cannabis use has been reported to induce long-lasting psychotic disorders and a dose-response relationship has been observed. We performed a systematic review of studies that investigate the association between the degree of cannabis consumption and psychosis and a meta-analysis to quantify the magnitude of effect. Published studies were identified through search of electronic databases, supplemented by manual searches of bibliographies. Studies were considered if they provided data on cannabis consumption prior to the onset of psychosis using a dose criterion (frequency/amount used) and reported psychosis-related outcomes. We performed random effects meta-analysis of individual data points generated with a simulation method from the summary data of the original studies. From 571 references, 18 studies fulfilled inclusion criteria for the systematic review and 10 were inserted in the meta-analysis, enrolling a total of 66 816 individuals. Higher levels of cannabis use were associated with increased risk for psychosis in all the included studies. A logistic regression model gave an OR of 3.90 (95% CI 2.84 to 5.34) for the risk of schizophrenia and other psychosis-related outcomes among the heaviest cannabis users compared to the nonusers. Current evidence shows that high levels of cannabis use increase the risk of psychotic outcomes and confirms a dose-response relationship between the level of use and the risk for psychosis. Although a causal link cannot be unequivocally established, there is sufficient evidence to justify harm reduction prevention programs.

Indexed as

Dose-Response Relationship, DrugCannabisHumansPsychoses, Substance-Induceddose responsedrug usepsychotic disordersschizophreniasystematic review

Identifiers

PMID26884547
PMCPMC4988731

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.