Depression from childhood into late adolescence: Influence of gender, development, genetic susceptibility, and peer stress.

TLDR

Depression is a debilitating mental illness that follows clear developmental patterns from childhood through late adolescence. The study aimed to test whether a genetic vulnerability‑stress model involving the 5‑HTTLPR polymorphism and chronic peer stress is moderated by developmental factors. Using the Gene Environment Mood (GEM) accelerated longitudinal cohort of 665 youths, researchers repeatedly administered semistructured diagnostic interviews every six months over three years to model depression trajectories and examine the interaction of genotype, peer stress, and development. Results showed that depression prevalence matched prior epidemiological trajectories, increased during middle to late adolescence, and that older adolescents with the SS/SL genotype and high chronic peer stress, as well as girls with high peer stress, were most likely to develop depressive episodes, indicating that genetic susceptibility and peer stress jointly predict depression risk.

Abstract

Depression is a debilitating mental illness with clear developmental patterns from childhood through late adolescence. Here, we present data from the Gene Environment Mood (GEM) study, which used an accelerated longitudinal cohort design with youth (N = 665) starting in 3rd, 6th, and 9th grades, and a caretaker, who were recruited from the general community, and were then assessed repeatedly through semistructured diagnostic interviews every 6 months over 3 years (7 waves of data) to establish and then predict trajectories of depression from age 8 to 18. First, we demonstrated that overall prevalence rates of depression over time, by age, gender, and pubertal status, in the GEM study closely match those trajectories previously obtained in past developmental epidemiological research. Second, we tested whether a genetic vulnerability-stress model involving 5-HTTLPR and chronic peer stress was moderated by developmental factors. Results showed that older aged adolescents with SS/SL genotype, who experienced higher peer chronic stress over 3 years, were the most likely to be diagnosed with a depressive episode over time. Girls experiencing greater peer chronic stress were the most likely to develop depression. This study used repeated assessments of diagnostic interviewing in a moderately large sample of youth over 3 years to show that depression rates increase in middle to late adolescence, or postpubertally, and that the gender difference in depression emerges earlier in adolescence (age 12.5), or postpubertally. Additionally, genetically susceptible older adolescents who experience chronic peer stress were the most likely to become depressed over time.