Implications of epidemiological data for identifying persons with substance use and other mental disorders

The authors conducted systematic searches in standard databases using key search terms related to epidemiology, prevalence, and co-occurring substance use and other mental disorders (COD), as well as specific combinations of drug and mental disorders. The authors targeted high-quality, large sample epidemiological surveys so as to utilize studies of high methodological rigor in the construction of recommendations for clinical identification. Further refined searches to identify these studies revealed common themes and related research gaps. Findings suggest that clinicians should have increased expectation that a patient with a substance use disorder (SUD) has a co-occurring mental disorder if the SUD is relatively severe, if the patient began using substances (including tobacco) at an early age, is female, is dependent on nicotine, or has a drug use disorder. Patients identified as having at least one SUD and one co-occurring mental disorder should be assessed to identify other likely CODs, because disorders are not normally distributed and tend to cluster in relatively few individuals.