Association between cannabis use and symptom dimensions in schizophrenia spectrum disorders: an individual participant data meta-analysis on 3053 individuals
Mathilde Argote, Guillaume Sescousse, Jérôme Brunelin, Grégoire Baudin, Michael P Schaub, Rachel A Rabin, Thomas Schnell, Petter Andreas Ringen, Ole A. Andreassen, Jean Addington, Paolo Brambilla, Giuseppe Delvecchio, Andreas Bechdolf, Thomas Wobrock, Thomas Schneider-Axmann, Daniela Herzig, Christine Mohr, Regina Vila‐Badia, Judith Usall I Rodié, Jasmina Mallet, Valerio Ricci, Giovanni Martinotti, Karolína Knížková, Mabel Rodríguez, Jacob Cookey, Philip G. Tibbo, Freda Scheffler, Laila Asmal, Clemente García‐Rizo, Sílvia Amoretti, Christian G. Huber, Heather Thibeau, Emily Kline, É. Fakra, Renaud Jardri, Mikail Nourredine, Benjamin Rolland
EClinicalMedicine September 8, 2023 DOI: 10.1016/j.eclinm.2023.102199 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Individual participant data meta-analysis (IPDMA) Longitudinal Peer reviewed |
|---|---|
| Sample size | 3,677 |
| Population | Individuals with schizophrenia spectrum disorders, comparing cannabis users (cannabis use disorder or use at least twice a week) with non-users |
| Measures | Positive and Negative Syndrome Scale (PANSS) |
| Topics | Cannabis |
| Citations | 31 |
| Key findings | Relative to non-use, cannabis use was associated with higher positive symptom severity (adjusted mean difference 0.34-0.38), lower negative symptom severity (aMD -0.49 to -0.50), and higher excitement (aMD 0.16), with no association for disorganization or depression. The authors state no causal relationship can be inferred and that effect sizes are small with wide confidence intervals, so findings should be interpreted with caution. |
Abstract
Background: The association between cannabis use and positive symptoms in schizophrenia spectrum disorders is well documented, especially via meta-analyses. Yet, findings are inconsistent regarding negative symptoms, while other dimensions such as disorganization, depression, and excitement, have not been investigated. In addition, meta-analyses use aggregated data discarding important confounding variables which is a source of bias.
Methods: PubMed, ScienceDirect and PsycINFO were used to search for publications from inception to September 27, 2022. We contacted the authors of relevant studies to extract raw datasets and perform an Individual Participant Data meta-analysis (IPDMA). Inclusion criteria were: psychopathology of individuals with schizophrenia spectrum disorders assessed by the Positive and Negative Syndrome Scale (PANSS); cannabis-users had to either have a diagnosis of cannabis use disorder or use cannabis at least twice a week. The main outcomes were the PANSS subscores extracted via the 3-factor (positive, negative and general) and 5-factor (positive, negative, disorganization, depression, excitement) structures. Preregistration is accessible via Prospero: ID CRD42022329172.
Findings: Among the 1149 identified studies, 65 were eligible and 21 datasets were shared, totaling 3677 IPD and 3053 complete cases. The adjusted multivariate analysis revealed that relative to non-use, cannabis use was associated with higher severity of positive dimension (3-factor: Adjusted Mean Difference, aMD = 0.34, 95% Confidence Interval, CI = [0.03; 0.66]; 5-factor: aMD = 0.38, 95% CI = [0.08; 0.63]), lower severity of negative dimension (3-factor: aMD = -0.49, 95% CI [-0.90; -0.09]; 5-factor: aMD = -0.50, 95% CI = [-0.91; -0.08]), higher severity of excitement dimension (aMD = 0.16, 95% CI = [0.03; 0.28]). No association was found between cannabis use and disorganization (aMD = -0.13, 95% CI = [-0.42; 0.17]) or depression (aMD = -0.14, 95% CI = [-0.34; 0.06]).
Interpretation: No causal relationship can be inferred from the current results. The findings could be in favor of both a detrimental and beneficial effect of cannabis on positive and negative symptoms, respectively. Longitudinal designs are needed to understand the role of cannabis is this association. The reported effect sizes are small and CIs are wide, the interpretation of findings should be taken with caution.
Funding: This research did not receive any specific grant or funding. Primary financial support for authors was provided by Le Vinatier Psychiatric Hospital.