Psychiatric and substance use disorders in individuals with hepatitis C: epidemiology and management.

Hepatitis C virus (HCV) infection is a major health concern in the US as well as in other countries worldwide. Treatment issues and disease management strategies are complicated by the extremely high rate of psychiatric and substance use disorders in those who have HCV. The majority of new and existing cases of HCV are related to injection drug use and, in this population, the prevalence of psychiatric comorbidity is high. Optimally, all patients with HCV should be screened for psychiatric and substance use disorders before initiation of antiviral therapy. If a patient screens positive, he or she should be referred to a mental healthcare provider or addiction specialist, assessed for the presence of a psychiatric or substance use disorder, and appropriately treated prior to initiation of antiviral (i.e. interferon) therapy. Although interferon-based therapies can lead to severe neuropsychiatric adverse effects, including in rare instances suicide, evidence suggests that many patients with comorbid psychiatric and substance use diagnoses can be treated safely and effectively using comanagement strategies. However, most patients with HCV are not treated with antiviral therapy. Therefore, we must expand our definition of HCV 'treatment' to include treatment of the comorbid psychiatric and substance use disorders that accompany HCV infection and precede antiviral therapy. This paper reviews the epidemiology and management of psychiatric and substance use disorders in patients with HCV, the issue of psychiatric and substance use disorders as contraindications for antiviral therapy, and current treatment strategies for HCV patients with these comorbid conditions.