With the exception of alcohol disorders, gender differences were few, inconsistent, and did not become apparent until late adolescence and young adulthood, similar to trends observed in the MTF and NSDUH studies (Johnston et al., 2008; SAMHSA, 2008). Gender differences in alcohol disorders beyond age 18 were consistent with past studies (Sher et al., 2005) which showed that young adult males were more frequently diagnosed with alcohol SUDs. On the other hand, rates of tobacco dependence were similar for males and females during and after adolescence. Gender differences in marijuana SUDs were not marked during adolescence but SUDs were more prevalent in males in young adulthood. Thus, as we expected, the gender gap was minimal when our sample was in adolescence; however, the overall prevalence for males rose to a much greater degree from adolescence to young adulthood than it did in females. Previous studies reporting similar changes across these developmental periods have attributed these differentially increasing rates of SUDs to the fact that alcohol and illicit substance use problems are frequently comorbid with other psychopathology such as antisocial personality disorder, which is much more common among males (Hicks et al., 2007).
