Schizophrenia and Comorbid Substance Use Disorder: Effects of Antipsychotics

The rate of comorbid substance use disorder in patients with schizophrenia is 3 times higher thanthat in the general population. Men with schizophrenia appear to be particularly vulnerable to substanceuse disorders. Substances commonly abused in patients with schizophrenia include alcohol,cannabis, and cocaine. Although the basis of comorbidity is unclear, a number of theories have beenproposed, including the possibility of a deficiency in the dopamine-mediated mesocorticolimbic brainreward circuit. Data suggest that substance abuse may complicate and worsen the course of schizophrenia.Early intervention with appropriate pharmacotherapy may prove beneficial and potentiallyimprove the long-term course of the disorder. Conventional antipsychotics have not been overly usefulin this patient population, but some atypical antipsychotics have been shown to reduce the use ofalcohol, cannabis, cocaine, and tobacco in patients with schizophrenia. Further research is required,but early evidence suggests that at least some atypical antipsychotics may prove to be therapeuticallyeffective in the treatment of patients with schizophrenia and comorbid substance use disorder.