Predictors of transitions across stages of heroin use and dependence prior to treatment-seeking among people in treatment for opioid dependence

Background and aims: Little is known about transition pathways among heroin users prior to treatment. This study examined the demographic and clinical predictors of transition speed from heroin use, to dependence, to first treatment episode. Methods: 1149 heroin-dependent participants recruited from opioid agonist treatment clinics in Sydney, Australia, underwent a structured interview. Age of onset (AOO) was collected for heroin use, dependence and treatment-seeking, childhood maltreatment, psychiatric history and other substance dependence. Discrete-time survival analyses modelled years from onset of use to dependence, and from dependence to treatment-seeking, including demographic and clinical covariates. Findings: Median AOO for first heroin use, dependence and treatment-seeking was 18 years (inter-quartile range, or IQR = 6), 21 years (IQR = 7), and 24 years (IQR = 10) respectively. In adjusted models, younger birth cohorts (vs. born <1960), greater childhood maltreatment and later AAO of first heroin use were associated with more rapid transitions from heroin use to dependence. Living independently, parental violence, and alcohol dependence were associated with slower transitions. Earlier treatment-seeking was associated with younger birth cohorts, having dependent children and later AOO of dependence. Delayed treatment-seeking was associated with <10 years school education, living independently, depression and alcohol dependence. Conclusions: In this treatment sample, onset of heroin use occurred during late adolescence, suggesting the need for targeted interventions in mid-adolescence. Transitions to heroin dependence, then treatment-seeking, occurred during early adulthood. Rapid transitions from use to dependence were associated with younger birth cohorts, greater exposure to childhood maltreatment, and later onset of use.