Cannabis-related measures were assessed using the Semi-Structured Assessment for the Genetics of Alcoholism19 (SSAGA). Cannabis exposure was a dichotomous variable representing whether an individual reported ever using cannabis during their lifetime. Age of onset of cannabis use (reported age of first cannabis use) and lifetime frequency of use (reported number of times using cannabis across one’s lifetime) were also examined (both coded ordinally by the HCP, eMethods S3).
