17]. Fifth, lack of information on the number and duration of dependence remission episodes experienced over the individual’s lifetime limits our understanding of the role of these factors on dependence remission and relapse. Sixth, factors that may help explain the racial-ethnic differences, such as socio-economic status could not be included in the models as a time-dependent covariate since the NESARC, as most large scale surveys, does not include information on changes in income over time.
