a and b
Cumulative Hazard Functions for (a) Alcohol and (b) Marijuana Initiation, by ADHD Subtype Diagnosis
The y-axis is the probability of initiation use in the next year for each group. Hazard functions of groups sharing the same superscript (i.e., either a or b) did not differ significantly at p < .05. When effects on marijuana initiation were adjusted based on alcohol initiation prior to or at the same age as marijuana (as it was for 80% of marijuana users), effect sizes for both types of ADHD symptoms on marijuana initiation were substantially reduced, though still highly significant (p < .0001).