A number of factors were associated with both transitions studied. Female gender was associated with slower progression to both opportunity and dependence. It is interesting to note that gender differences held across both transitions given that previous research has found males more likely to have opportunity to use cannabis, but has found these gender differences do not extend to the transition into drug use once opportunity has occurred (van Etten et al., 1999). Similarly, weekly tobacco use was associated with increased hazard of both cannabis use opportunity and progression to cannabis dependence, consistent with existing findings relating to dependence (Wagner and Anthony, 2002). Conduct disorder was associated with faster progression to both opportunity and dependence, echoing previous research showing disruptive or aggressive behaviour in both males and females is associated with earlier opportunity to use cannabis (Storr et al., 2011). Parental drug problems were significantly associated with a more rapid transition to both opportunity and dependence, in line with existing research relating to opportunity (Benjet et al., 2013). This factor most clearly demonstrated changes in the magnitude of effect size
