The Dynamics of Depression from Adolescence to Early Adulthood

This paper employs a conditional quantile regression approach to quantify the dynamics of depression among adolescents, and examine the extent of true state dependence in youth depression conditional on unobserved individual heterogeneity and family socio5economic status. We use data on the children of the US National Longitudinal Survey of Youth 79 cohort (CNLSY79) and employ a recently5developed instrumental variable approach for the estimation of dynamic quantile regression models with fixed effects. Our results suggest that true state dependence in youth depression is very low and the observed positive association between previous depression and current depression is mainly due to time5invariant unobserved individual heterogeneity. The results also show heterogeneity in true state dependence in youth depression across quantiles of the depression distribution.