Cannabis use and outcome of recent onset psychosis
Anton Grech, Jim van Os, Peter B. Jones, Shon W. Lewis, Robin Murray
European Psychiatry June 1, 2005 DOI: 10.1016/j.eurpsy.2004.09.013 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 119 |
| Population | Patients with recent onset of psychosis |
| Duration | 4-year follow-up |
| Topics | Cannabis |
| Key findings | Persistent cannabis use was associated with more positive symptoms and a more continuous illness at follow-up, but not with negative symptoms. The authors suggest that cannabis use may increase the risk of a more continuous illness with more positive symptoms. |
Abstract
AbstractPurposeTo test the hypothesis that recent onset psychotic patients who use cannabis will have psychotic symptoms that are more severe and more persistent than those who do not use cannabis.Subjects and methodsWe carried out a 4-year follow-up study of a cohort of 119 patients with recent onset of psychosis. The patients were divided into four groups according to duration of cannabis use, taking index admission and follow-up as reference points.ResultsThose subjects who persisted in the use of cannabis had more positive (but not negative) symptoms and a more continuous illness at follow-up.LimitationsThe main limitations of the study were: the relatively small sample size, and that the excess of male subjects and the presence of cannabis induced psychosis could have a confusing impact on the interpretation of the results.ConclusionIt is possible that psychotic patients who use cannabis are at a greater risk of a more continuous illness with more positive symptoms than those who do not.
Comparable studies
Other observational and cohort studies on cannabis, most cited first.
| Study | Year | Design | Participants |
|---|---|---|---|
| High-potency cannabis and the risk of psychosis People with first episode of psychosis and healthy controls from the local population | 2009 | Case-control study | n = 454 |
| Ayahuasca-Assisted Therapy for Addiction: Results from a Preliminary Observational Study in Canada Rural aboriginal population | 2013 | Observational study | |
| Impaired cognitive performance in drug free users of recreational ecstasy (MDMA) Otherwise healthy young people | 2000 | Observational | |
| Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study Individuals from the general population in Germany aged 14-24 at baseline | 2011 | Observational cohort | n = 1,923 |
| Cannabis-induced psychosis and subsequent schizophrenia-spectrum disorders: follow-up study of 535 incident cases Patients treated for cannabis-induced psychotic symptoms in Denmark between 1994 and... | 2005 | Observational cohort | n = 535 |
Citations in the library
Cited by 49
- Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study BMJ March 1, 2011
- Effects of cannabis use on outcomes of psychotic disorders: systematic review The British Journal of Psychiatry October 31, 2008
- 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 Schizophrenia Bulletin July 25, 2010
- Poor medication adherence and risk of relapse associated with continued cannabis use in patients with first-episode psychosis: a prospective analysis The Lancet Psychiatry July 10, 2017
- The Effect of Cannabis Use and Cognitive Reserve on Age at Onset and Psychosis Outcomes in First-Episode Schizophrenia Schizophrenia Bulletin March 9, 2011
and 44 more in the library
Cites 3
- ‘Gone to pot’: pharmacological evidence supporting the contribution of cannabinoid receptor function to psychosis CRC Press eBooks June 25, 2004
- Psychosis and Cannabis Abuse in the Gambia The British Journal of Psychiatry December 1, 1993
- Cannabis and psychotic illness. The British Journal of Psychiatry November 1, 1992