Do individuals with a severe mental illness experience greater alcohol and drug-related problems? A test of the supersensitivity hypothesis.

The supersensitivity hypothesis posits that individuals with a severe mental illness (i.e., schizophrenia and bipolar disorder; SMI) are more likely to be diagnosed with a substance abuse as opposed to a substance dependence diagnosis, and experience greater negative consequences associated with substance use at lower levels of consumption, as compared with non-SMI substance abusers. This is the first known study to test this hypothesis with a control group of non-SMI substance abusing individuals. Forty-two individuals with only a substance use disorder (SUD-only) and 53 dually diagnosed individuals (DD) were compared on measures of substance use, alcohol and drug dependence, negative consequences, substance use outcome expectancies, and motivation for change. A third group of SMI-only individuals (i.e., no SUD; n=35) were also recruited and all three groups were compared on psychological symptoms. Substance use, negative consequences, substance use outcome expectancies, motivation for change, and severity of alcohol and drug dependence were not found to differ significantly between the DD and SUD-only groups. However, the DD group had significantly greater levels of psychological symptoms, as compared with the SMI-only and SUD-only groups. Overall, this study does not provide support for the supersensitivity hypothesis.

Relapse to alcohol and drug use among individuals diagnosed with co-occurring mental health and substance use disorders: a review.

This paper reviews the literature investigating relapse to alcohol and drug use among individuals dually diagnosed with a substance use and a co-occurring mood, anxiety, schizophrenia-spectrum, or personality disorder. Prevalence rates for each co-occurring set of disorders are discussed, followed by research studies that examine predictors of relapse to substance use within these groups. Relevant conceptual models well-suited to incorporating relapse as an outcome variable, and psychiatric factors both as predictor and outcome variables, are presented. Suggestions for future studies are provided. A priority area is developing and using consistent and well-articulated definitions of relapse across studies. Several diagnostic issues surfaced such as using structured clinical interviews to determine diagnosis (preferably following detoxification from alcohol and/or drugs), separating individuals with only alcohol use disorders from those with alcohol and drug use disorders in analyses, reporting the rates and types of overlap in mental health diagnoses, and conducting analyses that include and exclude multiply disordered individuals. Finally, future studies that focus on isolating predictors of relapse and abstinence could make substantive contributions to improving treatment for individuals with co-occurring substance use and mental health disorders.