Purpose: To evaluate the influences of personality traits and nonsevere life events on depressive episodes in a 1-year follow-up in nonreferred adolescents. Methods: Participants were 2,773 students aged 12 to 16 years randomly selected from six middle schools in Taiwan who were assessed both at baseline for personality traits and depressive symptoms and at I year later for negative life events and depressive symptoms. Two, single, or no episodes of depression were based on whether the scores of the Center for Epidemiologic Studies Depression crossed over the cutoff of 28 at two time points. Multinomial logistic regression analyses were used to correlate personality or negative life events, which were trichotomized by means of tertiles or number of events, with the episodes of depressive symptoms. Results: After controlling for possible confounders, only elevated neuroticism was associated with a single episode of depressive symptoms, whereas a medium level or above of neuroticism, extraversion, or negative life events all exhibited association with the occurrence of two episodes. No interactions were found between all personality traits or between personality and negative life events. Conclusions: The relations of personality traits or nonsevere life events to depressive symptoms depend on whether the episode is an initial one. A high level in neuroticism is a critical vulnerability factor for the initiation of depressive symptoms in adolescents. Once the threshold has been surpassed, the influences of various personality traits and nonsevere life events on the subsequent depressive symptoms become cumulative and exhibit a dose- response relationship. ; 公共衛生學系 ; 公共衛生學院 ; 期刊論文