Publication

Abstract : Background Major Depressive Disorder (MDD) is a broad heterogeneous construct resolving into several symptom-clusters by factor analysis. The aim was to find the factor structures of MDD as per Montgomery and Asberg Depression Rating Scale (MADRS) and whether they predict escitalopram response. Methods In a longitudinal study at a tertiary institute in north India, 116 adult out-patients with non-psychotic unipolar MDD were assessed with MADRS before and after treatment with escitalopram (10–20mg) over 6–8 weeks for drug response. Results For total 116 patients pre-treatment four factor structures of MADRS extracted by principal component analysis with varimax rotation altogether explained a variance of 57%: first factor ‘detachment’ (concentration difficulty, lassitude, inability to feel); second factor ‘psychic anxiety’ (suicidal thoughts and inner tension); third ‘mood-pessimism’ (apparent sadness, reported sadness, pessimistic thoughts) and fourth ‘vegetative’ (decreased sleep, appetite). Eighty patients (68.9%) who completed the study had mean age 35.37±10.9 yrs, majority were male (57.5%), with mean pre-treatment MADRS score 28.77±5.18 and majority (65%) having moderate severity (MADRS <30). Among them 56 (70%) responded to escitalopram. At the end of the treatment there were significant changes in all the 4 factor structures (p <0.01). Vegetative function was an important predictor of response (p <0.01, odd's ratio: 1.3 [1.1–1.6] 95% CI). Melancholia significantly predicted non-response (p =0.04). Conclusions Non-psychotic unipolar major depression having moderate severity in north Indian patients as per MADRS resolved into four factor-structures all significantly improved with adequate escitalopram treatment. Understanding the factor structure is important as they can be important predictor of escitalopram response.