Background: It is alleged that depression distorts the assessment of general personality traits. To test that hypothesis, we examined scores on the Revised NEO Personality Inventory (NEO-PI-R) administered to acutely depressed patients at baseline and 14 to 26 weeks after treatment with antidepressant medication.
Method: Two hundred and fifty patients completed the NEO-PI-R at baseline, 109 patients after 14 to 26 weeks of antidepressant pharmacotherapy. 48 patients (49.5%) were identified as responders while 49 (50.5%) were identified as non-responders. The remaining 12 patients were excluded because they met HRSD response criteria but not the SCID-I MDD criteria at treatment completion.
Results: At baseline, NEO-PI-R scales showed high internal consistency and replicated the normative factor structure, suggesting that psychometric properties were preserved. Among non-responders, retest correlations were uniformly high (rs=.50 to .88) and mean levels showed little change, providing evidence for the consistency of personality self-reports during an acute depressive episode. NEO-PI-R scales showed construct validity in the concurrent prediction of a number of clinical criteria. Effective treatment had significant effects on the mean levels of neuroticism, which decreased, and extraversion, openness, and conscientiousness, which increased.
Limitations: The participants were from a clinical database and were not randomly assigned for the treatment.
Conclusions: The results suggest that the effect of acute depression is to amplify somewhat the personality profile of people prone to depression. Rather than regard these depression-caused changes in assessed personality trait levels as a distortion, we interpret them as accurate reflections of the current condition of the individual. Personality traits have biological bases, and when they are changed (by disease or therapeutic interventions) trait levels change.