Externalizing and internalizing disorders in childhood: studies on developmental psychopathology

Background: In taxonomic systems of child psychopathology, externalizing and internalizing disorders are differentiated. Objective: The question of whether a specific pathogenesis and etiology becomes discernible for these diagnostic categories was addressed. Method: In a prospective longidudinal study of 362 children born with different organic and psychosocial risks, emotional and behavioral problems from infancy to school age were assessed using a standardized clinical interview. At the age of 3 months infants were observed interacting with their mothers. Results: Externalizing disorders manifested themselves earlier, were more frequent at every age, and showed a greater stability than internalizing disorders. Early indicators of later disorder; became apparent in toddlerhood. In particular, externalizing disorders were associated with early psychosocial risks. Dysfunctional patterns of mother-child interaction in early infancy emerged as precursors of later disorders in school age. Conclusions: The results support the notion of distinct categories of developmental psychopathology.