Quality of life across domains among individuals with treatment-resistant depression

Abstract

Background: Treatment-resistant depression affects millions of people worldwide and is a leading cause of disability and suicide. Studies of treatment-resistant depression outcomes have traditionally focused on depressive symptoms and functional impairment. Quality of life (QoL) has not been well described. We aimed to measure QoL in individuals with treatment-resistant depression and to determine how QoL was related to traditional measures of symptoms and social functioning.

Methods: We used a reliable, cross-culturally validated questionnaire, the abbreviated World Health Organization Quality of Life scale (WHOQOL-BREF), to prospectively measure QoL in 79 patients with treatment-resistant depression who were referred for electroconvulsive therapy at a United States tertiary-care medical center. QoL was characterized in four domains: physical, psychological, social, and environmental. QoL domains were examined for association with demographic variables, patient-reported depressive symptoms, functional impairment, and childhood adversity, as well as clinician-rated scales.

Results: Relative to published international norms, mean QoL scores were low in physical (standardized score, z = -2.0), psychological (z = -2.6), and social (z = -1.0) domains, but not in the environmental domain (z = 0.2). After controlling for age and income, patient-rated depressive symptoms correlated with physical (Pearson correlation, r = -0.26) and psychological (r = -0.43) QoL, whereas adverse childhood experiences correlated with environmental QoL (r = -0.33). Patient-rated functional impairment correlated modestly with all domains (r = -0.25 to -0.39). Surprisingly, QoL correlated very weakly with clinician-rated measures. These modest associations of QoL with other clinical scales were confirmed in multiple regression analyses.

Limitations: We used a single QoL instrument, which did not allow us to directly compare the WHOQOL-BREF scale with other commonly used instruments. Our sample was recruited from a single academic medical center in the Midwest region of the United States and was largely Caucasian. These factors may limit generalizability to other settings and ethnicities.

Conclusion: Among individuals with treatment-resistant depression, QoL is lowest in the psychological and physical domains. QoL is only modestly correlated with patient-rated symptoms and functioning, and even more weakly correlated with clinician-rated scales, indicating that measures of symptoms and functioning cannot serve as QoL proxies. QoL should be assessed when caring for patients with treatment-resistant depression. When developing novel biological, psychological, and social interventions for treatment-resistant depression, QoL should be targeted as a distinct clinical outcome.

Keywords: Bipolar disorder; Childhood adversity; Functional impairment; Major depressive disorder; Quality of life; Treatment-resistant depression.

Figure 1.

Distributions of WHOQOL-BREF scores in four domains. Each panel shows the distribution of z-scores, calculated based on published international norms, for the sample of subjects with treatment-resistant depression (N=79). For example, a z-score of 0 represents QoL at the international mean; a z-score of –2 represents QoL two standard deviations below the international norm. The normative sample was demographically similar to our sample: 53% vs 65% female; mean age 45 vs 49 years; 60% vs 52% married or partnered.