Long-term follow-up of people with co-existing psychiatric and substance use disorders: patterns of use and outcomes.

The aims of this study were to document long-term patterns of substance use among people with co-existing psychiatric and substance use disorders and to explore differences in psychosocial outcomes for groups with different substance use outcome profiles (persistent hazardous, intermittent hazardous and non-hazardous users). An opportunistic long-term (4 - 6 years) follow-up interview was conducted with participants from a previous study who were recruited during their inpatient admission at a public psychiatric hospital in Newcastle, New South Wales, Australia. Follow-up data were obtained from 47 people from the original study and combined with their existing baseline, 6-month and 12-month data. The follow-up interview included demographic variables and measures of substance use, psychiatric symptomatology and a range of psychosocial variables. Alcohol, cannabis and amphetamines were the most commonly misused substances. Persistent hazardous users experienced poorer outcomes in the domains of social functioning and psychiatric symptomatology, including depression, than intermittently hazardous or non-hazardous users. An unusually high mortality rate of 10% among the males in the original sample (12/120) was an unexpected finding, particularly as this was likely to be an underestimate. Given the differences in outcomes between groups with varied gradations of substance use, a harm minimisation approach for research and practice among people with co-existing psychiatric and substance use disorders is endorsed.