Problem behaviors in early childhood (birth to five) are associated with poor outcomes in adolescence and adulthood, including delinquency, engagement in criminal activity and violence, and depression (Bornstein, Hahn, & Haynes, 2010; Liu, 2004; O’Connell, Boat, & Warner, 2009). These problem behaviors can be externalizing or internalizing. Externalizing behaviors are directed outward and include aggression, disruptive behavior, and oppositional defiance; internalizing behaviors are directed inward and include withdrawal, anxiety, or depression.

This research brief synthesizes experimental evaluations of 50 programs. The evaluations assessed program impacts on externalizing behaviors and/or internalizing behaviors among children ages birth to five. Evaluations of 27 programs assessed externalizing behaviors exclusively; 22 program evaluations assessed both externalizing and internalizing behaviors; and one assessed internalizing behaviors exclusively. Most of the evaluations focused on preschool children, or those ages three to five.