A case-linkage study of comorbidity in mental health and substance misuse care populations

Abstract

This study examines the total comorbid care ‘care population’ for one geographical area. It identifies the extent of (often unrecognized) shared care between coterminous ‘care populations’ in the context of the extent of assessed need and so identifies the gap between need and service provision. The study combined anonymized data for the total secondary mental health care population and all six substance misuse agency populations within one health authority population (N = 646,239) over three years, to identify shared ‘dual agency’ comorbid client groups (all mental health agency clients receiving specialist substance misuse treatment and vice versa). Of the total population of drug agency clients (N = 1206), 28% had received mental health services, and of alcohol agency clients (N = 1476), 39% had received mental health services. For a total mental health population (N = 19,029), 2% had received specialist drug services, and 3% alcohol services. These figures are compared to previous estimates of assessed need in treatment populations to identify gaps in service provision. Two thirds of ‘dual agency comorbid’ clients were male, 40% had attended Accident and Emergency (A&E) and half had been mental health in-patients. Mental health/drug agency populations were younger and mental health/alcohol agency populations received more mental health services.