OBJECTIVES: To explore the existence and clinical implications of symptomatic factors in patients with major depressive episodes.
METHODS: Data are from a 6-month prospective, non-interventional, observational study that included 1,549 MDD patients without sexual dysfunction in twelve countries. Depression severity was measured using the Clinical Global Impression (CGI) and the 16-item Quick Inventory of Depressive Symptomatology Self-Report (QIDS-SR16). Pain and quality of life were measured using the pain related items of the Somatic Symptom Inventory (SSI) and the EuroQoL-5D, respectively. The QIDS-SR16 and the SSI items were jointly included in a factor analysis. Exploratory factor analysis (EFA) was conducted in a randomly selected half of the sample and confirmatory factor analysis (CFA) in the remaining half.
RESULTS: The EFA showed that a four factor model explained the data apropriately (RMSEA 0.041, 90%CI 0.034- 0.048; CFI 0.979). The four factors were mood (feeling sad, concentration/decision making, self criticism, suicidal thoughts, interest in people or activities, energy/fatigability, psychomotor retardation and agitation); sleep (initial, middle insomnia, early awakening and sleeping too much); appetite and weight, and pain (muscle soreness, cramps in abdomen, pain in lower back, pain in heart or chest, pain in joints, neck pain, headache). The CFA showed good fit indexes for this four-factor model (RMSA 0.054, 90% CI 0.049-0.059; CFI 0.954). There was a highly statistical significant correlation (Spearman) between each of the four factors and CGI severity score and quality of life at each of the visits, with higher scores in the factors (higher severity) associated with higher CGI and lower quality of life (p less than 0.001, all comparisons).
CONCLUSIONS: Considering the results presented, the data reasonably support that pain symptoms be included in the evaluation of patients with major depression. More severe pain symptoms are associated to higher severity of depression and lower quality of life.
