Developmental Course of Personality Disorder Traits in Childhood and Adolescence.

Developmental patterns of personality pathology traits are not well delineated from childhood through late adolescence. In the present study, participants (N = 675, 56% female) were recruited to create three cohorts of third (n = 205), sixth (n = 248), and ninth (n = 222) graders to form an accelerated longitudinal cohort design. We assessed six PD (avoidant, dependent, histrionic, narcissistic, borderline, schizotypal) traits based on DSM-IV trait diagnostic conceptualizations via parent report at baseline, 18 months, and 36 months. According to parent report, mean levels of avoidant, dependent, histrionic, narcissistic, borderline, and schizotypal traits all declined for both boys and girls. The changes in dependent and histrionic traits were of medium effect size, and the changes in avoidant, narcissistic, borderline, and schizotypal traits were of small effect size. Over the 3 years of the study, the traits of each PD also demonstrated moderate to high rank-order stability.