Substance use disorder comorbidity among inpatient youths with psychiatric disorder

Substance abuse/dependence has been reported to show significant association with psychopathology, and is likely to influence the course and outcome of psychiatric illness. The aim of this study was to determine the rate of substance use disorders (other than alcohol) comorbidity among inpatient adolescents with severe Axis 1 psychiatric disorder.

A retrospective analysis of systematically collected data was carried out. The subjects were 16-18-year-old youths, admitted to an inpatient unit for severe psychiatric disorder. The data collection process utilized the DSM-IV criteria for diagnostic categorization of psychiatric disorder and substance use disorder. Demographic data, and data on suicide attempts were also collected.

Over a period of one year (March 2001-March 2002), 62 patients were admitted to the Christchurch Youth Inpatient Unit; 40 (64.5%) had a comorbid Substance Abuse Disorder (SAD) according to DSM-IV criteria and none had a Substance Dependence Disorder. The vast majority involved cannabis and stimulants. Sixty per cent of those with mood disorder, 63% of those with anxiety disorder and 80% of those with schizophrenia spectrum disorder had a comorbid SAD. Internalizing problems, especially mood disorders, pre-dominated among those with SAD reflecting the Unit's admission criteria. There were no differences in attempted suicide rates between those with SAD and those without SAD, but those with SAD were more likely to have unstable accommodation/living arrangements than those without SAD.

Our findings confirm previous reports suggestive of high rates of SAD comorbidity among youth with severe psychiatric illness. There are clinical and process implications for these findings particularly identification of substance use disorders and their treatment as well as resource availability and staff training.