Anxiety, depression and somatization (the internalizing cluster) are highly comorbid, prevalent and associated with significant individual and societal costs. Although prior studies have examined their natural course, there has been a little investigation into how symptoms unfold at the individual level. We examined the intraindividual (within-person) temporal patterning of symptom development and the impact of risk factors (sex, ethnicity, socioeconomic indicators, bullying victimization, child maltreatment) on symptom means and trajectories (between-person), comparing youth and parent reports.
Over a 7-year interval from age 11 to 17, children (
n= 669; 54% girls; 79% White) and parents (89% mothers) reported on symptoms of anxiety and depression from age 11 and somatization from age 13. Autoregressive latent trajectory models with structured residuals were used to uncouple within- and between-person sources of variance. Results
According to self-reports, generalized anxiety consistently predicted depression, while anxiety and depression consistently predicted somatization. Anxiety also had an indirect effect on somatization via depression. According to parent reports, there were several bidirectional effects between anxiety and depression and between depression and somatization. Experiences of abuse were consistent risk factors for self-reported internalizing symptoms, and across informants, girls had higher symptom means and rising trajectories compared to boys.
Generalized anxiety plays an important role in adolescent depressive and somatic symptoms. Primary prevention of anxiety may be warranted to curb symptom continuity and the development of comorbidity. Research is needed to determine whether self-reports of anxiety should be prioritized over parent reports and continued efforts are needed to reduce bullying and child maltreatment.