Predictors of Changes in Depressive Symptoms with Major Depressive Disorder - A Naturalistic 6-month Follow-up Study

There are limited reports, particularly in naturalistic settings, regarding predictors of clinical outcomes in patients with major depressive disorder (MDD). The objective of this observational, retrospective study is to describe 6-month clinical outcomes and identify their predictors among patients with MDD in Japan.

A total of 546 patients diagnosed with MDD at their first visit were enrolled in this naturalistic follow-up study, of whom 217 completed follow-up assessments at six months. Depressive symptoms were measured using the Japanese Quick Inventory of Depressive Symptomatology (QIDS-J). Potential predictors, including demographic characteristics, personality traits (assessed using the Ten Item Personality Inventory-Japanese version [TIPI-J]), and psychotic symptoms (measured by the PRIME Screen-Revised [PS-R]), were analyzed.

Among the 217 follow-up completers, 38% achieved response, and 20% reached remission. Persistent symptoms, particularly mid-nocturnal insomnia, remained prevalent at follow-up. Higher baseline depressive severity, presence of view of myself symptom, endorsement of suspiciousness/persecutory ideas, and lower educational attainment were consistently associated with greater depressive symptom severity at six months. Additionally, a robust association was observed between openness to experience and remission, while absence of view of myself symptom and endorsement of first-rank symptoms consistently predicted remission.

This study identified significant predictors of clinical outcomes in MDD patients over a 6-month period. These findings underscore the importance of considering baseline symptoms, personality traits, and psychosocial factors in predicting MDD outcomes, informing more tailored treatment strategies in real-world clinical practice.