Psychiatric Multimorbidity in a Specialized Program for Severely Mentally Ill Veterans.

It has been suggested that psychiatric multimorbidity may better characterize severely impaired psychiatric patients than individual severe mental illness (SMI) diagnoses, and that these patients may be better served by centers offering integrated co-located, psychiatric and social services than in conventional clinics providing one-to-one care. We tested the hypothesis that multimorbidity is a critical characteristic of Veterans treated at a co-located multi-service Veteran's Health Administration (VHA) program originally established to treat Veterans living with SMI. Administrative data from the VA Connecticut Health Care System from fiscal year 2012 were used to compare veterans using diverse mental health and social services at the Errera Community Care Center (ECCC), an integrated "one-stop shop" for SMI veterans, and those seen exclusively at standard outpatient mental health clinics. Bivariate and multiple logistic regression analyses were used to compare groups on demographic characteristics, psychiatric and medical diagnoses, service utilization, and psychotropic medication fills. Results: Of the 11,092 veterans included in the study, 2281 (20.6%) had been treated at the ECCC and 8811 (79.4%) had not. Multivariable analysis highlighted the association of treatment in the ECCC and younger age, lower income, homelessness, and especially multimorbidity including both multiple substance use and multiple psychiatric diagnoses. Programs originally designed to address the diverse needs of patients living with SMI and homelessness may be usefully characterized as treating patients with psychiatric multimorbidity, a term of greater clinical relevance. Effectiveness research is needed to evaluate the one-stop shop approach to their treatment.