Unveiling the symptom structure of major depressive disorder and exploring its role in treatment response

Major depressive disorder (MDD) is a heterogeneous clinical syndrome that is increasingly recognized as comprising multiple symptom factors. However, the optimal factor structure and its role in predicting the response to drug treatment in MDD remain unclear.

We performed the 17-item Hamilton Depression Rating Scale (HDRS-17) and Hamilton Anxiety Rating Scale (HARS) on a large sample of MDD patients and obtained 31-item scores for each patient at baseline. We then evaluated the symptom factor structure using exploratory and confirmatory factor analysis. Additionally, we analyzed changes in the factor scores of MDD patients after 2, 8, and 26 weeks of antidepressant treatment. Finally, we constructed a logistic regression model to evaluate the predictive efficacy of baseline symptom factors for antidepressant treatment in MDD patients.

Using factor analysis in 360 MDD patients, we identified an 8-factor model representing somatization, depression, sleep, anxiety, libido, insight, appetite, and suicide factors, respectively. Depression, suicide, and sleep factor scores showed the most significant changes during antidepressant treatment, while somatization and anxiety factors showed moderate changes. The scores of appetite, libido, and insight factors showed the most minor changes. Multivariate logistic regression analysis identified sleep, libido, and appetite factors at baseline as independent predictors for symptom remission after 26 weeks of antidepressant treatment.

The 8-factor model is a good fit and is clinically interpretable in MDD. Factor scores may provide a powerful tool for antidepressant response analysis in MDD patients.