HealthDay News — Cannabis use is associated with psychosis symptoms (PS) during adolescence, according to a research letter published online June 6 in JAMA Psychiatry.
Josiane Bourque, from the University of Montreal, and colleagues examined year-to-year associations between cannabis use and PS over four years among 3,720 adolescents who completed confidential annual surveys from age 13 to 16 years. A multilevel approach was used to test for within-person differences that inform on the extent to which increased cannabis use precedes an increase in PS and vice versa.
The researchers first tested a basic model containing only autoregressive paths, random intercepts, and within-time correlations across variables; this was followed by testing a transactional model that also contained cross-lagged correlations. The transaction model was favored in the Χ²-difference test. Statistically significant positive cross-lagged associations were revealed at every time point from cannabis use to PS reported 12 months later in the transactional model, exceeding the random intercepts of cannabis use and PS. These correlations were similar in size to the autoregressive link between PS from ages 15 to 16. There was a statistically significant association for PS at age 15 years with cannabis use at age 16 years.
“This analysis demonstrates a predominant association at the individual level of cannabis use frequency with increased PS, and not the opposite, in the general population at a developmental stage when both phenomena have their onset,” the authors write.