Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study
Rebecca Kuepper, Jim van Os, Roselind Lieb, Hans‐ulrich Wïttchen, Michael Höfler, Cécile Henquet
BMJ March 1, 2011 DOI: 10.1136/bmj.d738 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 1,923 |
| Population | Individuals from the general population in Germany aged 14-24 at baseline |
| Duration | 10-year follow-up with assessments at baseline, 3.5 years, and 8.4 years |
| Measures | Munich version of the Composite International Diagnostic Interview (M-CIDI) |
| Topics | Cannabis |
| Citations | 307 |
| Key findings | Incident cannabis use from baseline to T2 increased the risk of later incident psychotic symptoms from T2 to T3 (adjusted odds ratio 1.9, 95% CI 1.1 to 3.1). Continued cannabis use increased the risk of persistent psychotic symptoms (odds ratio 2.2, 95% CI 1.2 to 4.2). Incidence rates of psychotic symptoms were higher in exposed versus non-exposed individuals at both intervals. |
Abstract
Objective: To determine whether use of cannabis in adolescence increases the risk for psychotic outcomes by affecting the incidence and persistence of subclinical expression of psychosis in the general population (that is, expression of psychosis below the level required for a clinical diagnosis).
Design: Analysis of data from a prospective population based cohort study in Germany (early developmental stages of psychopathology study).
Setting: Population based cohort study in Germany.
Participants: 1923 individuals from the general population, aged 14-24 at baseline. MAIN OUTCOME MEASURE: Incidence and persistence of subthreshold psychotic symptoms after use of cannabis in adolescence. Cannabis use and psychotic symptoms were assessed at three time points (baseline, T2 (3.5 years), T3 (8.4 years)) over a 10 year follow-up period with the Munich version of the composite international diagnostic interview (M-CIDI).
Results: In individuals who had no reported lifetime psychotic symptoms and no reported lifetime cannabis use at baseline, incident cannabis use over the period from baseline to T2 increased the risk of later incident psychotic symptoms over the period from T2 to T3 (adjusted odds ratio 1.9, 95% confidence interval 1.1 to 3.1; P=0.021). Furthermore, continued use of cannabis increased the risk of persistent psychotic symptoms over the period from T2 to T3 (2.2, 1.2 to 4.2; P=0.016). The incidence rate of psychotic symptoms over the period from baseline to T2 was 31% (152) in exposed individuals versus 20% (284) in non-exposed individuals; over the period from T2 to T3 these rates were 14% (108) and 8% (49), respectively.
Conclusion: Cannabis use is a risk factor for the development of incident psychotic symptoms. Continued cannabis use might increase the risk for psychotic disorder by impacting on the persistence of symptoms.
In the evidence
This study is part of the evidence base for a synthesis in the library. Here is how each one recorded it.
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State of the evidence: Cannabis Supports
Incident cannabis use increased risk of later incident psychotic symptoms (adjusted OR 1.9) and continued use increased risk of persistent psychotic symptoms (OR 2.2) over a 10-year follow-up.
Synthesized
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 | |
| 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 |
| Assessment of addiction severity among ritual users of ayahuasca Regular ayahuasca users (jungle-based and urban-based) and matched controls | 2010 | Observational cohort | n = 127 |
Citations in the library
Cited by 46
- Gone to Pot – A Review of the Association between Cannabis and Psychosis Frontiers in Psychiatry May 22, 2014
- Cannabis use and first-episode psychosis: relationship with manic and psychotic symptoms, and with age at presentation Psychological Medicine May 24, 2013
- Cannabis use and vulnerability for psychosis in early adolescence—a TRAILS study Addiction December 10, 2012
- Course of cannabis use and clinical outcome in patients with non-affective psychosis: a 3-year follow-up study Psychological Medicine February 5, 2015
- Alcohol confounds relationship between cannabis misuse and psychosis conversion in a high‐risk sample Acta Psychiatrica Scandinavica January 9, 2015
and 41 more in the library
Cites 7
- Causal association between cannabis and psychosis: examination of the evidence The British Journal of Psychiatry January 30, 2004
- Evidence that familial liability for psychosis is expressed as differential sensitivity to cannabis: an analysis of patient-sibling and sibling-control pairs. Archives of General Psychiatry February 2011
- Behavioral sensitization to delta 9-tetrahydrocannabinol and cross-sensitization with morphine: differential changes in accumbal shell and core dopamine transmission. Journal of Neurochemistry August 2008
- Does normal developmental expression of psychosis combine with environmental risk to cause persistence of psychosis? A psychosis proneness–persistence model Psychological Medicine April 1, 2007
- Is Cannabis Use a Contributory Cause of Psychosis? The Canadian Journal of Psychiatry August 1, 2006
and 2 more in the library