The long-term treatment outcomes of depression and anxiety comorbid with substance abuse

Abstract

The impact of the comorbidity of psychiatric disorder and substance abuse on treatment outcomes was estimated using data from a longitudinal survey of 1,920 individuals who were followed nearly 15 years. Individuals with anxiety or depression symptoms at baseline generally experienced increased distress at follow-up; those who received mental health treatment experienced decreased distress at follow-up. Individuals with substance abuse/dependence symptoms who received treatment at baseline had a higher risk of follow-up disability; treated individuals with substance abuse who had comorbid anxiety and depression symptoms at baseline were at lower risk of disability at follow-up. Individuals with anxiety and depression symptoms at baseline had a higher incidence of chronic illness during follow-up; those who received treatment or had substance abuse symptoms did not. The results may improve understanding of the degree to which treatment of a primary disorder may prevent the incidence or reduce the prevalence of a secondary comorbid disorder.