OBJECTIVE: Patients with major depressive disorder (MDD) frequently suffer from concomitant somatic symptoms. This study aims to investigate the existence of a group of patients depending on the presence of somatic symptoms and to understand the impact of these symptoms on the course of depression.
METHODS: Nine hundred and nine patients from Asia presenting with a new or first episode of MDD (DSM-IV/ICD-10) were enrolled in this 3-month prospective observational study. Depressive symptoms (Hamilton Depression Scale-HAMD-17 and Clinical Global Severity score – CGI-S) and somatic symptoms (Somatic Symptom Inventory) were assessed. A cluster analysis was used to define patient groups based on the presence of somatic symptoms. Confirmatory factor analysis was used to classify somatic symptoms in different groups. Regression models were employed to assess the relevance of somatic symptoms on outcomes.
RESULTS: A three cluster solution was chosen based on the variance explained. Cluster 1 patients (39%) had a low level of somatic symptoms. Cluster 2 patients (53%) had a significant level of somatic symptoms. Cluster 3 patients (8%) had severe somatic symptoms. Patients with more somatic symptoms at baseline had more severe depression (HAMD17 and CGI-S) and lower response and remission rates. Response rates were 82% in cluster 1, 72% in cluster 2 and 55% in cluster 3. Remission rates were 68%, 55% and 29% respectively. Four groups of symptoms were validated with the confirmatory factor analysis: as Pain, Autonomic Symptoms, Energy and CNS symptoms. A regression model showed patients with pain symptoms had a lower response (OR = 0.65; 95% CI 0.53–0.80) and remission rates (OR = 0.61; 95% CI 0.49–0.74).
CONCLUSION: Somatic symptoms are frequent in Asian patients with MDD. Patients with more somatic symptoms have higher depression severity and lower response and remission rates. Pain symptoms are most associated with poorer outcomes.
