Young adults who used cannabis 2 to 3 times per week were shown to be at increased risk for hypomania at age 22 to 23 years, according to the results of a recent study published in Schizophrenia Bulletin.
Participants from a UK birth cohort were assessed for frequency of cannabis use at age 17. In this study, cannabis use 2 to 3 times per week was considered frequent use. At age 22 to 23 years, participants responded to a postal survey that included the Hypomania Checklist Questionnaire-32 to evaluate manic symptoms.
Information about depression symptoms, psychotic symptoms, childhood abuse, and substance use were collected at various times throughout the participants’ lives. The association among these variables, hypomania, and cannabis use were assessed using path analysis.
After adjustment, frequent cannabis use was associated with subsequent hypomania (odds ratio [OR] 2.21). Weekly cannabis use (OR 2.87) was more strongly associated with hypomania compared with any cannabis use (OR 1.82).
In unadjusted analyses, frequent cannabis use was significantly associated with an increased risk for depression (OR 2.48) and psychotic symptoms (OR 3.33).
In path analysis, cannabis use correlated well with subsequent hypomania after controlling for all pathways. Depression and psychotic symptoms did not mediate the association between hypomania and cannabis use. The association of subsequent hypomania with gender and childhood abuse were significantly mediated by cannabis use.
The study authors concluded that, “adolescent cannabis use is an independent risk factor for future hypomania, and the nature of the associations found is suggestive of a causal link, [al]though the gold standard for inferring causality of course remains intervention.”
Marwaha S, Winsper C, Bebbington P, Smith D. Cannabis use and hypomania in young people: a prospective analysis [published online November 28, 2017]. Schizophr Bull. doi:10.1093/schbul/sbx158