Co-occurring psychiatric disorders and alcoholism.

Alcohol use disorder (AUD), a term that comprises both alcohol abuse and alcohol dependence, is a highly prevalent psychiatric disorder. Over 50% of treated AUD patients also suffer from other psychiatric disorder(s). Detailed study has revealed disorders across multiple psychiatric domains with rates of co-occurrence far greater than chance, suggesting a synergistic relationship. The basis of this synergy is explored along with its multiple forms, including behavioral and neurobiologic. Specific topics include the predisposition to both AUD and co-occurring psychopathology, the vulnerability to environmental risk factors that exacerbate these predispositions, and the nature of reinforcement in acute intoxication. Co-occurrence can also modify and exacerbate the neuroadaptations underpinning chronic dependence and relapse, the manifestations of acute and protracted withdrawal, emergence of medical and psychiatric complications, and ultimately the potential for relapse. The outcomes of co-occurrence as well as the unique impact it has on proper treatment are also discussed. Throughout, the significance of recognizing co-occurrence is emphasized since, both neurobiologically and clinically, the synergies between co-occurring disorders yield a result far more complex than a mere sum of the component disorders.