Comorbidity patterns in dual diagnosis across seven European sites

Background and Objectives: Psychiatric inpatients with substance use disorders are a significant public health concern due to grave consequences including increased risk of self harm, homicide as well as poor clinical outcome. The present study aims to examine and compare patterns of comorbidity (i.e. concurrent substance use disorders and severe mental illness) among psychiatric inpatients across seven European sites.Methods: 352 patients were included consecutively from psychiatric inpatients units at 7 European sites and interviewed with the Mini- International Neuropsychiatric Interview and the European version of the Addiction Severity Index questionnaires. For analysis the psychiatric diagnostic groups were organized into broader categories.Results: Concurrent alcohol use disorder and mood disorder was found to be the most prevalent comorbidity pattern (30.8%) across Europe. Alcohol or drug use disorder combined with mood disorder was most prevalent among females and in the older age group whereas mixed substance use and psychosis was more frequent among males and younger participants. Finally, differences in comorbidity patterns were found at different European sites.Conclusions: The prevalence of different comorbidity patterns varied across European clinical settings. Significant differences between comorbidity subgroups were found with regard to age and gender.