Homotypic and heterotypic continuity of symptoms of psychiatric disorders from age 4 to 10 years: a dynamic panel model.

Homotypic and heterotypic continuities of symptoms of childhood psychiatric disorders are mostly due to unobserved time-invariant factors. Nonetheless, symptoms of earlier behavioral disorders may affect later symptoms of such disorders and of ADHD, and ADHD may increase the risk of later anxiety. Thus, even if interventions do not alter basic etiological factors, symptom reduction may itself cause later symptom reduction.