2007). The higher risk of transitioning to cannabis and cocaine dependence among those individuals with later use onset, may also be due to the emergence of more intense patterns of use, greater availability and affordability of these drugs in late adolescence and higher social acceptability (Bachman et al., 1998; Behrendt et al., 2009; Kandel, 2002). Consistent with previous findings (Behrendt et al., 2009), the positive association between early onset of nicotine use and transition to dependence remained significant after controlling for other covariates.
