Comorbid schizophrenia and substance abuse: a review of epidemiology and course

Over the last dozen years, our knowledge regarding comorbid schizophrenia (SCZ) and substance use disorder (SUD) has evolved in several ways. First, the rate of lifetime comorbid SCZ-SUD appears to have increased another 20-30%, so now about 70-80% of persons with SCZ have lifetime SUD. Second, early remission of SUD has become commonplace among patients with SCZ, perhaps outnumbering the number of SCZ-only patients as well as those with active SCZ-SUD. Third, sustained SUD remission is well demonstrated, though the rates may yet be low. Fourth, research on comorbid SCZ-SUD is filling out our knowledge in many areas, including the characteristics of SCZ patients at risk for SUD, reasons SCZ patients seek out substances, effects of various substances on SCZ course and symptoms, and obstacles to SUD recovery in people with SCZ. The influence of SUD treatment and self-help on epidemiology and course has not been adequately evaluated. Primary prevention and early treatment of SUD in SCZ patients are still relatively neglected, though they offer our greatest hope for enhancing the lives of people with SCZ and improving the cost efficacy of care.