To identify factors associated with hazard of the development of dependence following the opportunity to use cannabis survival data (time in years, starting from age of first opportunity to use cannabis) were used for analysis of 2,593 participants who had reported their age of opportunity to use cannabis and who had also reported lifetime cannabis use (those who had not reported lifetime cannabis use were removed from the model in order to avoid the inverse association that would exist between never-use of cannabis and cannabis dependence; additionally, one participant was omitted as their recorded age of dependence was earlier than recorded age of opportunity). The failure event was cannabis dependence, and 371 failures were observed. Due to missing covariate data, 2,565 participants were included in the final model (363 failure events).
