Detection of Subclinical Depression in Bipolar Disorder: A Cross-Sectional, 4-Month Prospective Follow-Up Study at Community Mental Health Services (SIN-DEPRES)

Objective: The aim of this study was to assess the prevalence and the impact of depressive symptoms on the functional outcome of bipolar disorder outpatients in remission.

Method: A cross-sectional, prospective 16-week study of a cohort of 739 euthymic bipolar disorder patients (DSM-IV-TR criteria) recruited by 94 investigators was conducted. Clinical stability was assessed at baseline and at week 16 with the modified Clinical Global Impressions Scale-Bipolar Version, and depressive symptoms were assessed at baseline with the 17-item Hamilton Depression Rating Scale (HDRS-17 [primary endpoint measure]), the Montgomery-Asberg Depression Rating Scale (MADRS), and the self-applied Center for Epidemiologic Studies-Depression Scale (CES-D). Functional status was evaluated with the Social and Occupational Functioning Assessment Scale (SOFAS) and Social Adaptation Self-evaluation Scale (SASS). The study was conducted from April 2006 to March 2007.

Results: Subclinical depressive symptoms (SDS) were detected on the HDRS-17 in 16.9% of the sample. In symptom-free patients, the incidence of new SDS after 16 weeks was 20% (MADRS score > 7). At baseline, SDS patients compared to non-SDS patients presented with poorer social-occupational performance (SOFAS score mean difference, −11.9; 95% CI, −14.2 to −9.6) and poorer social adjustment (SASS score mean difference, −5.6; 95% CI, −7.1 to -4.1). Depressive symptoms were inversely related to functional status and social adjustment: MADRS-SOFAS correlation coefficients, r = −0.54 (P < .0001), and MADRS-SASS correlation coefficients, r = −0.42 (P < .0001). The self-applied survey identified additional cases with depressive symptoms, showing an SDS total prevalence of 44.9%.

Conclusions: Depressive symptoms in apparently remitted bipolar disorder outpatients are not rare and result in a decline in occupational outcome and social maladjustment.

J Clin Psychiatry

Submitted: February 25, 2009; accepted June 9, 2009.

Online ahead of print: August 10, 2010 (doi:10.4088/JCP.09m05177gre).

Corresponding author: Eduard Vieta, PhD, Hospital Clinic & CIBERSAM, Villarroel 170, 08036 Barcelona, Spain ([email protected]).