UC Davis

Youth undergo numerous social, biological, and cognitive changes from late childhood through young adulthood. Many of these changes impact their temperament, or individual differences in reactivity and self-regulation that are present from an early age and relatively enduring. Temperament, in turn, is related to various domains of psychological adjustment, especially mental health. This dissertation is comprised of three chapters. In Chapter 1, I examined the latent structure of the most commonly used measure of adolescent temperament, the Early Adolescent Temperament Questionnaire-Revised (EATQ-R), and then showed that the resulting factors (i.e., Effortful Control, Negative Emotionality, and Positive Emotionality) had theoretically meaningful concurrent associations with several measures of adolescent functioning, supporting the construct validity of the EATQ-R. In Chapter 2, I examined how temperament from age 12 to 16 is associated with the onset of suicidal ideation and behaviors during adolescence and young adulthood. Finally, in Chapter 3, I examined how temperament develops across adolescence (age 10 to 16) and whether the developmental trajectories of temperament are associated with anxiety/depression during young adulthood (ages 19 and 21). Together, the results suggest that (1) the EATQ-R is a valid measure of adolescent temperament, (2) adolescents undergo meaningful temperament change across adolescence, and (3) these changes are associated with various aspects of psychological adjustment, especially mental health.