The DOI matches its Crossref record; 88 of the 90 references it cites were found in a registry or an index.
Continued versus discontinued cannabis use in patients with psychosis: a systematic review and meta-analysis
Abstract
Background Although the link between cannabis use and development of psychosis is well established, less is known about the effect of continued versus discontinued cannabis use after the onset of psychosis. We aimed to summarise available evidence focusing on the relationship between continued and discontinued cannabis use after onset of psychosis and its relapse. Methods In this systematic review and meta-analysis, we searched MEDLINE for articles published in any language from the database inception date up until April 21, 2015 that included a sample of patients with a pre-existing psychotic disorder with a follow-up duration of at least 6 months. We used a combination of search terms for describing cannabis, the outcome of interest (relapse of psychosis), and the study population. We excluded studies if continued cannabis use or discontinued cannabis use could not be established. We compared relapse outcomes between those who continued (CC) or discontinued (DC) cannabis use or were non-users (NC). We used summary data (individual patient data were not sought out) to estimate Cohen's d, which was entered into random effects models (REM) to compare CC with NC, CC with DC, and DC with NC. Meta-regression and sensitivity analyses were used to address the issue of heterogeneity. Findings Of 1903 citations identified, 24 studies (16 565 participants) met the inclusion criteria. Independent of the stage of illness, continued cannabis users had a greater increase in relapse of psychosis than did both non-users (dCC-NC=0·36, 95% CI 0·22-0·50, p<0·0001) and discontinued users (dCC-DC=0·28, 0·12-0·44, p=0·0005), as well as longer hospital admissions than non-users (dCC-NC=0·36, 0·13 to 0·58, p=0·02). By contrast, cannabis discontinuation was not associated with relapse (dDC-NC=0·02, -0·12 to 0·15; p=0·82). Meta-regression suggested greater effects of continued cannabis use than discontinued use on relapse (dCC-NC=0·36 vs dDC-NC=0·02, p=0·04), positive symptoms (dCC-NC=0·15 vs dDC-NC=-0·30, p=0·05) and level of functioning (dCC-NC=0·04 vs dDC-NC=-0·49, p=0·008) but not on negative symptoms (dCC-NC=-0·09 vs dDC-NC=-0·31, p=0·41). Interpretation Continued cannabis use after onset of psychosis predicts adverse outcome, including higher relapse rates, longer hospital admissions, and more severe positive symptoms than for individuals who discontinue cannabis use and those who are non-users. These findings point to reductions in cannabis use as a crucial interventional target to improve outcome in patients with psychosis. Funding UK National Institute of Health Research.
Overview
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“A meta-analysis of longitudinal studies [54] found that continued cannabis use in people with psychosis is associated with an increased risk of relapse to psychosis and with longer hospital stays than in non-users [55].”
From Cannabis, cannabinoids and health: a review of evidence on risks and medical benefits (2025) · cites this paper as [54]
In the citing paper
“A meta-analysis of longitudinal studies [54] found that continued cannabis use in people with psychosis is associated with an increased risk of relapse to psychosis and with longer hospital stays than in non-users [55].”
From Cannabis, cannabinoids and health: a review of evidence on risks and medical benefits (2025) · cites this paper as [54]
Citations
Cites
Statistical Power Analysis for the Behavioral Sciences
Muller, K. E., & Cohen, J. (1989) · Technometrics · doi:10.2307/1270020 · Cited by 99,603
Statistical power analysis for the behavioral sciences
Cohen, J. (1990) · Computers Environment and Urban Systems · doi:10.1016/0198-9715(90)90050-4 · Cited by 65,417
Measuring inconsistency in meta-analyses
Higgins, J. P. T., Thompson, S. G., Deeks, J. J., & Altman, D. G. (2003) · BMJ · doi:10.1136/bmj.327.7414.557 · Cited by 63,139
Bias in meta-analysis detected by a simple, graphical test
Egger, M., Smith, G. D., Schneider, M., & Minder, C. (1997) · BMJ · doi:10.1136/bmj.315.7109.629 · Cited by 56,722
Cochrane Handbook for Systematic Reviews of Interventions: Cochrane Book Series
(2008) · doi:10.1002/9780470712184 · Cited by 25,048
von Elm, E., Altman, D. G., Egger, M., Pocock, S. J., Gøtzsche, P. C., Vandenbroucke, J. P., & Initiative, F. T. S. (2007) · PLoS Medicine · doi:10.1371/journal.pmed.0040296 · Cited by 23,020
Conducting Meta-Analyses in R with the metafor Package
Viechtbauer, W. (2010) · Journal of Statistical Software · doi:10.18637/jss.v036.i03 · Cited by 20,464
The Brief Psychiatric Rating Scale.
Overall, J. E., & Gorham, D. R. (1962) · Psychological Reports · doi:10.2466/pr0.1962.10.3.799 · Cited by 11,090
Borenstein, M., Hedges, L. V., Higgins, J. P. T., & Rothstein, H. R. (2021) · doi:10.1002/9781119558378 · Cited by 9,799
Regier, D. A. (1990) · JAMA · doi:10.1001/jama.1990.03450190043026 · Cited by 3,962
Research works printed but not linked: 3
- Isaac, 2005, Is cannabis an antipsychotic? The experience in psychiatric intensive care, Hum Psychopharmacol, 20, 207, 10.1002/hup.674 · DOI
- Linszen, 1994, Cannabis abuse and the course of recent-onset schizophrenic disorders, Arch Gen Psychiatry, 51, 273, 10.1001/archpsyc.1994.03950040017002 · DOI
- van Dijk, 2012, Effect of cannabis use on the course of schizophrenia in male patients: a prospective cohort study, Schizophr Res, 137, 50, 10.1016/j.schres.2012.01.016 · DOI
Cited by
Sorted by citations
The pharmacokinetics and the pharmacodynamics of cannabinoids
Lucas, C. J., Galettis, P., & Schneider, J. (2018) · British Journal of Clinical Pharmacology · doi:10.1111/bcp.13710 · Cited by 724
Murray, R. M., Quigley, H., Quattrone, D., Englund, A., & Forti, M. D. (2016) · World Psychiatry · doi:10.1002/wps.20341 · Cited by 332
Self-citationNon-Genetic Factors in Schizophrenia
Stilo, S. A., & Murray, R. M. (2019) · Current Psychiatry Reports · doi:10.1007/s11920-019-1091-3 · Cited by 369
Self-citationAssessing the public health impacts of legalizing recreational cannabis use: the US experience
Hall, W., & Lynskey, M. (2020) · World Psychiatry · doi:10.1002/wps.20735 · Cited by 255
Solmi, M., Toffol, M. D., Kim, J. Y., Choi, M., Stubbs, B., Thompson, T., Firth, J., Miola, A., Croatto, G., Baggio, F., et al. (2023) · BMJ · doi:10.1136/bmj-2022-072348 · Cited by 322
“85 In other words, use of cannabis when no psychotic disorder has already occurred increases the risk of its onset, and using cannabis after its onset, worsens clinical outcomes.”
BackgroundSelf-citation
Metadata
- Authors
- Schoeler, T., Monk, A., Sami, M. B., Klamerus, E., Foglia, E., Brown, R., Camuri, G., Altamura, A. C., Murray, R., & Bhattacharyya, S.
- Affiliations
- King's College London (GB)
- University of Milan (IT)
- Corresponding author
- Bhattacharyya, Sagnik
- Venue
- The Lancet Psychiatry
- Publisher
- Elsevier BV
- Published
- 2016-03
- Volume
- 3
- Issue
- 3
- Pages
- 215-225
- ISSN
- 2215-0366 (ISSN-L)
- OpenAlex
- W2257957527
- Cited by
- 322
- References
- 90
- Citations by year
- 2026: 17 · 2025: 25 · 2024: 33 · 2023: 34 · 2022: 39 · 2021: 28 · 2020: 39 · 2019: 34 · 2018: 30 · 2017: 24 · 2016: 18
- FWCI
- 4.07
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- The Lancet Psychiatry (publishedVersion)
- PubMed (publishedVersion)
- UCL Discovery (University College London) (submittedVersion)
- Research Portal (King's College London) (submittedVersion)
- Funders
- National Institute for Health and Care Research (NF-SI-0512-10110, NIHR-CS-011-001, RP-PG-0606-1049)
- Medical Research Council (MR/J012149/1, MR/K013807/1)
- Topics
- Health Sciences › Medicine › Pharmacology (medical) › Cannabis and Cannabinoid Research
- Health Sciences › Medicine › Psychiatry and Mental health › Schizophrenia research and treatment
- Health Sciences › Medicine › Epidemiology › Substance Abuse Treatment and Outcomes
- Keywords
- cannabis use, psychosis, relapse, hospitalization, positive symptoms, functioning, schizophrenia, bipolar disorder, schizoaffective disorder, delusional disorder, cannabis harm reduction, relapse prevention
- MeSH terms
- Humans, Marijuana Smoking, Psychotic Disorders, Recurrence
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
