Developmental trajectories of Big Five personality traits among adolescents and young adults: Differences by sex, alcohol use, and marijuana use

Objective Individual differences in adolescent personality are related to a variety of long-term health outcomes. While previous studies have demonstrated sex differences and non-linear changes in personality development, these results remain equivocal. The current study utilized longitudinal data (n = 831) from the National Consortium on Alcohol and Neurodevelopment in Adolescence to examine sex differences in the development of personality and the association between substance use and personality. Method Participants (ages 12-21 at baseline) completed the Ten-Item Personality Inventory and self-reported past year alcohol and marijuana use at up to 7 yearly visits. Data were analyzed using generalized additive mixed-effects models and linear mixed-effects models. Results Findings support linear increases in agreeableness and conscientious and decreases in openness with age and inform on timing of sex-specific non-linear development of extraversion and emotional stability. Further, results provide novel information regarding the timing of the association between substance use and personality, and replicate past reporting of differential associations between alcohol and marijuana use and extraversion, and sex-dependent effects of marijuana use on emotional stability. Conclusions These findings highlight the importance of modeling sex differences in personality development using flexible non-linear modeling strategies, and accounting for sex- and age-specific effects of alcohol and marijuana use.

Automated summary

This study examined the relationship between adolescent personality development and substance use using longitudinal data. The results showed that certain personality traits in adolescents exhibit linear changes with age, while others show non-linear changes that are specific to gender. Additionally, the study found associations between substance use and personality, with differential effects observed between alcohol and marijuana use and across genders.