Do cannabis and urbanicity co-participate in causing psychosis? Evidence from a 10-year follow-up cohort study
Rebecca Kuepper, Jim van Os, Roselind Lieb, H.-U. Wittchen, Cécile Henquet
Psychological Medicine October 1, 2011 DOI: 10.1017/s0033291711000511 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Longitudinal Peer reviewed |
|---|---|
| Sample size | 1,923 |
| Population | German adolescents and young adults aged 14-24 years at baseline from the Early Developmental Stages of Psychopathology cohort study |
| Duration | 10-year follow-up |
| Measures | Munich version of the Composite International Diagnostic Interview |
| Topics | Cannabis |
| Key findings | Cannabis use and urban upbringing interact: cannabis use increased the risk of incident psychotic symptoms by 6.8% in urban areas but showed no significant effect in rural areas, with a significant interaction (10.9% adjusted difference in risk). |
Abstract
BackgroundCannabis use is considered a component cause of psychotic illness, interacting with genetic and other environmental risk factors. Little is known, however, about these putative interactions. The present study investigated whether an urban environment plays a role in moderating the effects of adolescent cannabis use on psychosis risk.MethodProspective data (n=1923, aged 14–24 years at baseline) from the longitudinal population-based German Early Developmental Stages of Psychopathology cohort study were analysed. Urbanicity was assessed at baseline and defined as living in the city of Munich (1562 persons per km2; 4061 individuals per square mile) or in the rural surroundings (213 persons per km2; 553 individuals per square mile). Cannabis use and psychotic symptoms were assessed three times over a 10-year follow-up period using the Munich version of the Composite International Diagnostic Interview.ResultsAnalyses revealed a significant interaction between cannabis and urbanicity [10.9% adjusted difference in risk, 95% confidence interval (CI) 3.2–18.6, p=0.005]. The effect of cannabis use on follow-up incident psychotic symptoms was much stronger in individuals who grew up in an urban environment (adjusted risk difference 6.8%, 95% CI 1.0–12.5, p=0.021) compared with individuals from rural surroundings (adjusted risk difference −4.1%, 95% CI −9.8 to 1.6, p=0.159). The statistical interaction was compatible with substantial underlying biological synergism.ConclusionsExposure to environmental influences associated with urban upbringing may increase vulnerability to the psychotomimetic effects of cannabis use later in life.
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 7
- Cannabis and psychotic experiences Addiction June 29, 2017
- Cannabis and Psychosis: A Review of the Risk Factors Involved American Journal of Plant Sciences 2020
- Epidemiological and biological mechanisms of cannabis as cause of psychosis 2012
- Cross cultural studies on adolescent cannabis use and psychosis 2011
- Cannabis use in Adolescence and Risk of Psychosis: Are there Factors that Moderate this Relationship? A Systematic Review and Meta-Analysis Substance Abuse February 22, 2021
and 2 more in the library
Cites 6
- Continued cannabis use and risk of incidence and persistence of psychotic symptoms: 10 year follow-up cohort study BMJ March 1, 2011
- 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
- Family-based analysis of genetic variation underlying psychosis-inducing effects of cannabis: sibling analysis and proband follow-up. Archives of General Psychiatry February 2011
- Gene-environment interplay between cannabis and psychosis. Schizophrenia Bulletin November 1, 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
and 1 more in the library