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Cited by 322Cannabis and Cannabinoid ResearchSchizophrenia research and treatmentSubstance Abuse Treatment and Outcomes

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

Schoeler, Tabea, Monk, Anna, Sami, Musa B, Klamerus, Ewa, Foglia, Enrico, Brown, Ruth, Camuri, Giulia, Altamura, A Carlo, Murray, Robin, Bhattacharyya, Sagnik·2016·The Lancet Psychiatry
DOI 10.1016/s2215-0366(15)00363-6
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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.

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Crossref · 10.1016/s2215-0366(15)00363-6

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Research works printed but not linked: 3

  1. Isaac, 2005, Is cannabis an antipsychotic? The experience in psychiatric intensive care, Hum Psychopharmacol, 20, 207, 10.1002/hup.674 · DOI
  2. Linszen, 1994, Cannabis abuse and the course of recent-onset schizophrenic disorders, Arch Gen Psychiatry, 51, 273, 10.1001/archpsyc.1994.03950040017002 · DOI
  3. 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

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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
ORCID
Venue
The Lancet Psychiatry
Publisher
Elsevier BV
Published
2016-03
Volume
3
Issue
3
Pages
215-225
ISSN
2215-0366 (ISSN-L)
DOI
10.1016/s2215-0366(15)00363-6
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
Licence
www.elsevier.com/tdm/userlicense/1.0/ (tdm)
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

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