Symptom Profile and Clinical Course of Inpatients with Unipolar versus Bipolar Depression

BACKGROUND: Although differences in symptom profiles and outcome between depressive patients with an underlying major depressive disorder (MDD) and bipolar depression (BD) have been reported, studies with sequential short-interval assessments in a real-life inpatient setting are scarce.

OBJECTIVES: To examine potential differences in symptom profile and course of depressive symptomatology in depressive inpatients with underlying MDD and BD.

METHODS: A cohort of 276 consecutive inpatients with MDD (n = 224) or BD (n = 52) was followed during their hospitalization using routine outcome monitoring (ROM), which included a structured diagnostic interview at baseline (Mini-International Neuropsychiatric Interview Plus [MINI-Plus]) and repeated 17-item Hamilton Depression Rating Scale every 2 weeks. MDD and BD were compared regarding their symptom profiles and time to response and remission. Furthermore, the concordance between the MINI-Plus and clinical diagnosis was analyzed.

RESULTS: Patients were on average 52 and 47 years old in the MDD and BD group, respectively, and 66 versus 64% were female. Compared to patients with BD, patients with MDD scored higher on weight loss (p = 0.02), whereas the BD group showed a higher long-term likelihood of response (hazard ratio = 1.93, 95% confidence interval 1.16-3.20, p for interaction with time = 0.04). Although the same association was seen for remission, the interaction with time was not significant (p = 0.48). Efficiency between the MINI-Plus and clinical diagnosis of BD was high (0.90), suggesting that the MINI-Plus is an adequate ROM diagnostic tool.

CONCLUSIONS: In routine clinical inpatient care, minor differences in the symptom profile and the course of depressive symptomatology may be helpful in distinguishing MDD and BD, particularly when using sequential ROM assessments.