We also found gender differences in these relationships. We
replicated previous findings from this sample that more symptoms of
depression were related to increased frequency of marijuana use in
males, but not in females (Schuster et al., 2013), and notably, this effect
did not change as individuals transitioned into young adulthood. In
addition, higher frequency of cigarette usewasmore strongly associated
with higher frequency of marijuana use in males, and this effect did not
change over time. Among males, higher symptoms of depression and a
higher frequency of cigarette use were more strongly related to
increased frequency of marijuana use than lower symptoms of
depression and a higher frequency of cigarette use. Depression did
not, however, alter the relationship between higher frequency of
cigarette use and increased frequency of marijuana use for females.
These findings were specific to marijuana use frequency, as we did
not find gender differences or significant influence of symptoms of
depression on cigarette use frequency.