It is widely recognized that patients in psychiatric and substance disorder treatment settings commonly present with comorbid substance and psychiatric disorders [1–5]. For example, 44% of patients in psychiatric clinics in U.K. urban settings were also diagnosed with a substance use disorder, and 75% of patients in drug disorder services as well as 85% of patients in alcohol disorder services also had a mood or anxiety disorder [6]. The comorbidity is also common in community settings. For example, Grant and her colleagues reported that 20% of individuals with a mood disorder and 18% of individuals with an anxiety disorder in the National Epidemiologic Survey on Alcohol and Related Conditions also had a substance use disorder [3]. The comorbidity of these disorders makes treatment more challenging due to competing treatment needs of these individuals [7]. In addition, state policies and reimbursement restrictions have historically made it difficult for treatment services for substance and psychiatric disorders to offer integrated care [8, 9]. As a result, many patients with substance disorders and comorbid psychiatric disorders fail to receive the quality care that they need and are at increased risk for relapse and other adverse health outcomes [10–12].
