People with mental illness are more likely to be diagnosed with a substance use disorder than people without mental illness. For individuals with severe mental illness (SMI), substance use rates are even higher. Some SMI’s that have the highest levels of substance use disorder include depression, bipolar, and schizophrenia. This can make treating either condition more challenging. Therefore, it is essential to know if a client is dealing with substance abuse or substance dependency. Currently, several different diagnostic tools and assessment methods are used to determine the level of use. However, until now, no research has compared the validity and accuracy of these methods.
Sarah L. Desmarais of the Department of Psychology at North Carolina State University wanted to find out if one method was superior to another and tested several different approaches on a sample of 1,460 adults with schizophrenia. She used clinical ratings, collateral assessments, urine and hair tests, and self-reports and compared them to the Structured Clinical Interview for DSM-IV Disorders (SCID) ratings. She found that overall, the methods she used provided similar results to the SCID. She also found that none of the approaches provided clear distinction between substance dependence and substance abuse.
This finding was particularly concerning because it has been theorized that SMI prevents people from using substances without abusing them. However, that was not found to be supported in this study. In fact, many of the participants used substances without having significant impairment or dependency. But because dependency can have a dramatic impact on treatment and mental illness outcomes, it is important for future work to explore this issue more thoroughly. Until then, Desmarais believes her results show that there was not one test that clearly outperformed any other. She said, “Differences in diagnostic accuracy, when they were found, were relatively small in nature, providing limited support for superiority of one assessment approach over another.” In sum, she said that deciding which test to administer should be based on the overall treatment plan, financial limitations, and time constraints, and not on the minute differences in results from one test to another.
Reference:
Desmarais, S. L., Van Dorn, R. A., Sellers, B. G., Young, M. S., and Swartz, M. S. (2012). Accuracy of self-report, biological tests, collateral reports and clinician ratings in identifying substance use disorders among adults with schizophrenia. Psychology of Addictive Behaviors. Advance online publication. doi: 10.1037/a0031256

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