Objective: To prospectively measure the link between depressive symptoms and functional outcomes in the long-term treatment of people with schizophrenia.
Methods: Data were drawn from a large, multi-site, 3-year, prospective, naturalistic, observational study, in which subjects with schizophrenia were assessed at enrollment and at 12-month intervals thereafter. Individuals who were "Depressed" (defined as a total score > or =16 on the Montgomery-Asberg Depression Rating Scale) at enrollment were compared to those "Non-depressed" on functional outcomes, using self-report measures, clinicians' ratings, and information from medical records. Statistical analyses included Generalized Estimation Equation and mixed regression analyses adjusted for individual characteristics. Longitudinal group comparisons across the 3-year study were augmented with a cross-sectional group comparison at enrollment.
Results: At enrollment, 39.4% (877/2228) of the participants were deemed Depressed. Across the 3-year study, the depressed cohort was significantly more likely than the Non-depressed to use relapse-related mental health services (emergency psychiatric services, sessions with psychiatrists); to be a safety concern (violent, arrested, victimized, suicidal); to have greater substance-related problems; and to report poorer life satisfaction, quality of life, mental functioning, family relationships, and medication adherence. Furthermore, changes in depressed status were associated with changes in functional outcomes.
Conclusions: People with schizophrenia and concurrent depressive symptoms have poorer long-term functional outcomes compared to the Non-depressed. Their poorer quality of life, greater use of mental health services, and higher risk of involvement with law enforcement agencies underscore a need for special treatment interventions. Treatment of the non-psychotic dimensions of schizophrenia is a critical part of recovery.