used as a cutoff for determining which variables were included in one of six second stage models that were differentiated on conceptual grounds: demographic characteristics, mental health diagnoses, substance use variables, treatment history, family background and adult violence. Any variables that remained significant at p <0.05 at this second stage were entered into the final regression model. Separate models were run for males and females; age and employment status were controlled for in both models. Some variables (onset heroin use, panic disorder, emotional abuse, and physical abuse) were removed due to non-significance. Participants with five other substance dependence diagnoses were used as the reference group. All analyses were carried out using SPSS for Windows, version 15.0.
