An Examination of the Influence of Cannabis Use on Psychotic Symptom Exacerbation and Relapse in Early Psychosis
Griffith Research Online 2003 DOI: 10.25904/1912/1643 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort Peer reviewed |
|---|---|
| Sample size | 84 |
| Population | Participants assessed at admission for psychosis |
| Duration | 6-month follow-up |
| Topics | Cannabis |
| Key findings | Cannabis use preceded psychosis onset and predicted symptom severity at admission. Frequency and quantity of cannabis use predicted time to psychotic relapse over six months, and psychotic symptom severity predicted increased quantity of cannabis use. |
Abstract
There has been concern about the impact of cannabis use on the onset, course and relapse of psychosis. Evidence from retrospective and a small number of prospective studies has suggested that cannabis use may precipitate a latent psychosis, exacerbate psychotic symptoms and increase the likelihood of psychotic relapse. The purpose of the current study was to examine the influence of cannabis use on psychotic symptom exacerbation and relapse within the stress vulnerability-coping model of psychosis. Two studies were conducted. The influence of cannabis use on the onset and course of psychosis was retrospectively examined in the first study. The second study prospectively examined the influence of cannabis use on psychotic symptom exacerbation and relapse over a 6-month period. The influence of the severity of psychotic symptoms on a relapse in cannabis use was also explored. Eighty-four participants were assessed at admission, 81 of whom were followed up for a 6-month period. Measures consisted of structured diagnostic interviews and self-report measures of stress, medication compliance, family functioning, premorbid adjustment, quality of life, substance use and psychotic symptoms. The onset of cannabis use clearly preceded the onset of psychosis. Cannabis use was predictive of the severity of psychotic and general psychopathology symptoms at admission. Both the frequency and quantity of cannabis use was predictive of time to psychotic relapse over the 6-month follow up period. Psychotic symptom severity was predictive of a substantial increase in the quantity but not the frequency of cannabis use. Cannabis use was related to the onset, course and relapse of psychosis.
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 |