externalizing–internalizing
a broad classification of children’s behaviors and disorders based on their reactions to stressors. Externalizing behaviors and disorders are characterized primarily by actions in the external world, such as acting out, antisocial behavior, hostility, and aggression. Internalizing behaviors and disorders are characterized primarily by processes within the self, such as anxiety, somatization, and depression. See also Child Behavior Checklist. [proposed by U.S. psychologist Thomas M. Achenbach (1940– )]