Examining the association between affective disorders with psychotic features and cannabis use 30 days prior to admission to inpatient psychiatry in Ontario, Canada from 2015-2019.

Abstract

Background: Cannabis use is associated with the risk of developing psychosis. There is substantial research on the association between cannabis use and non-affective psychotic disorders, but few studies have examined the relationship between cannabis and affective disorder with psychotic features (ADPF). Objectives: To investigate the association between ADPF and cannabis use 30 days prior to admission to inpatient psychiatry and to explore the role of age and gender as effect modifiers. Methods: Data from the Ontario Mental Health Reporting System collected between 2016-2019 were used to conduct multivariable regression analyses. Binary logistic regression analyses were performed to investigate whether the odds of having used cannabis were greater among those with ADPF compared to those without ADPF and whether the association was moderated by age or gender. Results: Among those with affective disorders, those with psychotic features were at no greater odds of having used cannabis 30 days prior to inpatient psychiatric admission compared to those without psychotic features. Gender was found to modify the association between ADPF and cannabis exposure. Being female with ADPF was associated with lower odds of using cannabis prior to inpatient psychiatric admission than females without ADPF. Compared to males without ADPF, males with ADPF were at no greater odds of having used cannabis within 30 days prior to admission. Overall, a larger proportion of males used cannabis prior to admission, compared to females. Age was not found to modify the association between ADPF and cannabis exposure. Conclusion: In addressing gaps in the literature regarding cannabis use and affective psychotic disorders, the results of the study demonstrated a nuanced gender-based relationship between ADPF and cannabis use. Based on these findings, the study has implications for informing early intervention initiatives for harm reduction and clinical practice among persons with severe mental health concerns.