The average age of first cannabis use in the COGA analytic sample was 16 years (table 2), consistent with national trends.39 Lifetime CUD was prevalent in this subsample (70%), although most were classified as “mild” (40% of sub-sample; 25% “moderate”, 35% “severe”). Use of other illicit drugs was common in the analytic sample (75%). 74% of the analytic sample met lifetime criteria for an AUD. Between 12% (hallucinations) and 31% (decreased social contact; table 2) of the sample endorsed a cannabis-related experience with 46% reporting experiencing at least 1 of the 5 cannabis-related experiences. There were few significant differences between the European and African ancestry samples (online Supplementary materials). There were very minor to no differences in endorsement in those who were assessed with the SSAGA I vs those who were assessed with later SSAGAs (eg, the largest difference was for cognitive difficulties, which was endorsed by 23% of those who were assessed with SSAGA I vs 26% of those who were assessed with other SSAGAs.) In the CATS replication sample, 81% of individuals had a lifetime diagnosis of opioid use disorder (further details in supplementary table 1).
