Cannabis-associated symptom profiles in patients with first episode psychosis and population controls
Diego Quattrone, Laura Ferraro, Giada Tripoli, Erika la Cascia, Harriet Quigley, Eu-Gei Group, Charlotte Gayer‐Anderson, Peter Brian Jones, James Bowes Kirkbride, Daniele la Barbera, Ilaria Tarricone, Michael T. Lynskey, Tom P. Freeman, Pak Chung Sham, Alaistar Cardno, Evangelos Vassos, Jim van Os, Craig Morgan, Ulrich Reininghaus, Cathryn M. Lewis, Robin Murray, Marta Di Forti
bioRxiv (Cold Spring Harbor Laboratory) March 16, 2019 preprint DOI: 10.1101/577932 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Observational cohort |
|---|---|
| Sample size | 2,136 |
| Population | 901 first-episode psychosis patients and 1235 controls recruited across six countries in the EU-GEI study |
| Topics | Cannabis |
| Citations | 3 |
| Key findings | In first-episode psychosis patients, greater lifetime cannabis exposure was linearly associated with higher positive symptom scores, with daily high-potency users scoring highest (B=0.35), while negative symptoms were more common among never-users than users (B=-0.27). In controls, psychotic experiences were associated with current cannabis use but not lifetime extent of use. Depressive symptoms were unrelated to cannabis use in both groups. |
Abstract
Abstract Objective The evidence is mixed on whether cannabis use is associated with a particular symptomatology in first episode psychosis (FEP) patients. The authors set out to investigate a) patterns of association between cannabis use and transdiagnostic symptom dimensions; b) whether the extent of use of cannabis contributes to the variation in clinical and subclinical symptom profiles.
Method: The authors analysed data from 901 patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. Item response modelling was used to estimate two bifactor models, which included general and specific dimensions of psychotic symptoms in patients and psychotic experiences in controls. The associations between these dimensions and cannabis use was evaluated using linear mixed effects models analyses.
Results: In patients, there was a linear relationship between the positive symptom dimension and the extent of lifetime exposure to cannabis, with daily users of high potency cannabis having the highest score (B=0.35; 95%CI 0.14 to 0.56). Moreover, negative symptoms were more common among patients who never used cannabis compared with those with any pattern of use (B=-0.27; 95%CI −0.42 to −0.12). In controls, psychotic experiences were associated with current use of cannabis but not with the extent of lifetime use. Neither patients nor controls presented differences in the depressive dimension related to cannabis use.
Conclusions: The extent of use of cannabis explains part of the heterogeneous distribution of positive and negative symptoms of FEP patients.
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 |