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

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.

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

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.

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.

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.