A longitudinal study of personality traits, anxiety, and depressive disorders in young adults.

Background: How personality traits, anxiety, and depressive disorders relate longitudinally has implications for etiologic research and prevention. We sought to determine how neuroticism and extraversion relate to first-onset anxiety and depressive disorders in young adults.
Design: An inception cohort of 489 university freshmen was followed for 6 years.
Method: Participants self-reported personality traits using the Eysenck Personality Questionnaire. Anxiety and depressive disorders were assessed using the Diagnostic Interview Schedule.
Results: Baseline neuroticism predicted first-onset panic disorder, agoraphobia, generalized anxiety disorder (GAD), and major depressive disorder (MDD), while introversion predicted first-onset agoraphobia (moderate-large effects). Participants who developed panic disorder, agoraphobia, GAD, or MDD had increases in neuroticism if the disorder was current at follow-up (moderate-large effects). Participants who developed MDD but were in remission by follow-up had a moderate increase in neuroticism.
Conclusions: High neuroticism in young adulthood is either a true risk factor, or marker of risk, for first-onset anxiety and depressive disorders, as is low extraversion for agoraphobia. The current data suggest large neuroticism "state" effects for panic disorder, agoraphobia, and MDD, and moderate "scar" effects from MDD. Though many clinicians and researchers regard personality traits simply as "vulnerability" factors, longitudinal analyses suggest additional complexity.