Purpose of review: The comorbidity between psychiatric and substance use disorders remains an important phenomenon to understand, and an active area of investigation. The purpose of this review is to highlight key 2011 issues and novel findings on psychiatric and substance disorders comorbidity from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), a large national survey of the US general population.
Recent findings: Topics of active investigation included the internalizing/externalizing meta-structure of common mental disorders; the 10 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) personality disorders; the 3-year incidence and persistence of disorders; treatment of major depression; and many other topics not as easily categorized.
Summary: Meta-structure may increasingly offer a parsimonious way of addressing comorbidity, although adding new disorders adds complexity and the value of etiologic analyses utilizing broad dimensions of psychopathology rather than individual disorders is not yet fully known. Expanding the range of personality disorders beyond antisocial personality disorder appears essential in understanding the incidence and persistence of substance use disorders. Substance use disorders have low rates of treatment relative to major depression, but increase the likelihood of depression treatment among comorbid cases, a phenomenon that needs to be understood. These comorbidity studies provide much novel information, and indicate many potentially fruitful directions for new research.