The Distinct Patterns and Developmental Comorbidity of Adolescent Depressive Symptoms, Impulsivity, and Substance Use

Prior studies have highlighted the developmental patterns of depressive symptoms, impulsivity, and substance use separately among adolescents; however, few studies have simultaneously tested the distinct patterns over time and the developmental comorbidity using a robust sample of adolescents. Therefore, utilizing the network theory of psychopathology, the present study first estimated the distinct developmental trends of depressive symptoms, impulsivity, and substance use while simultaneously examining the longitudinal comorbidity across four-time points (n = 4,718). Results indicated that across four-time points, adolescents who endorsed baseline depressive symptoms, impulsivity, and substance use were also more likely to report continued symptoms over time. Cross-lagged results suggest that substance use across Times 1 through 3 positively predicted depressive symptoms across Times 2 through 4. However, depressive symptoms were not statistically predictive of substance use across Times 2 through 4. Furthermore, impulsivity across Times 2 and 3 was positively associated with substance use across Times 3 and 4. Lastly, substance use across Times 1 and 2 was statistically predictive of impulsivity across Times 2 and 3. Overall, these results suggest the distinct continuity of depressive symptoms, impulsivity, and substance use and highlight the partial developmental comorbidity of these symptoms across four-time points.