Background: Neuroticism and self-esteem, two commonly used personality constructs, are thought to reflect a person's underlying vulnerability to major depression. The relative strength of these predictors is not known.
Method: Information was gathered on 2163 individual women from an epidemiological sample of female female twin pairs. Neuroticism was assessed by the Eysenck Personality Questionnaire and global self-esteem by the Rosenberg Self-Esteem Scale. Major depression (DSM-III-R criteria) and stressful life events were also assessed. The personality constructs were studied in relation to major depression by logistic regression and structural equation modelling.
Results: Both cross-sectionally and prospectively, examined individually, neuroticism was a stronger predictor of risk for major depression than was self-esteem. When examined together, the predictive power of neuroticism remained substantial, while that of self-esteem largely disappeared. The same pattern of findings was obtained when a subset of subjects who had recently experienced stressful life events was analysed. By trivariate twin modelling, we found that the covariation of self-esteem, neuroticism and major depression was due largely to genetic factors. When self-esteem was the 'upstream' variable, a substantial genetic correlation remained between neuroticism and major depression. By contrast, when neuroticism was the 'upstream' variable, the genetic correlation between self-esteem and major depression disappeared.
Conclusions: The personality construct of neuroticism is a substantially better index of a woman's underlying vulnerability to major depression than is self-esteem. These findings suggest that overall emotionality or emotional reactivity to the environment reflects risk for depression better than does global self-concept.