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Frequent cannabis use may increase psychosis risk among teens
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Findings published in JAMA Psychiatry revealed a link between cannabis use frequency and increased psychosis symptoms at the individual level among Canadian adolescents.
“Considering that jurisdictions are moving toward cannabis legalization and the anticipated changes to the Canadian policy planned for July 2018, there is a need to understand whether cannabis use has a causal role in the development of psychiatric diseases, such as psychosis,” Patricia J. Conrod, PhD, from the department of psychiatry, University of Montreal, and colleagues wrote. “Prospective studies report a temporal precedence of cannabis use before later onset of psychosis, but the evidence is limited.”
Using random intercept cross-lagged panel models, the researchers evaluated year-to-year connections between cannabis use and symptoms of psychosis over 4 years in Canadian teens aged 13 years at study onset. This model tested within person differences to determine the extent to which an individual’s increase in cannabis use led to an increase in their psychosis symptoms, and vice versa.
Participants included 3,720 youth from 31 schools in the greater Montreal area who completed an annual web-based survey from age 13 to 16 years asking them to report past-year cannabis use — assessed with a 6-point scale where 0 indicated never and 5 indicated every day — and psychosis symptoms, assessed with the Adolescent Psychotic-Like Symptoms Screener.
Analysis of the transactional model showed statistically significant links between cannabis use and symptoms of psychosis at every time point reported 1 year later, over and above the random intercepts of cannabis use and psychosis symptoms that demonstrated between-person differences. Furthermore, participants with symptoms of psychosis at age 15 years were more likely to report using cannabis at age 16 years. The authors also found that all autoregressive links and within-time correlations showed statistically significance among teenagers aged 14, 15 and 16 years.
“Considering that [psychosis symptoms] are associated with risk for psychosis, as well as nonpsychotic disorders, these results emphasize the need for targeted cannabis use prevention as jurisdictions revise their cannabis regulatory policies,” Conrod and colleagues wrote. “Promoting evidence-based interventions and policies that reduce access to and demand for cannabis among youth could lead to population-based reductions in risk for major psychiatric conditions.” – by Savannah Demko
Disclosures: The authors report no relevant financial disclosures.