This parameter reviews the current status of reactive attachment disorder with regard to assessment and treatment. Attachment is a central component of social and emotional development in early childhood, and disordered attachment is defined by specific patterns of abnormal social behavior in the context of "pathogenic care." Clinically relevant subtypes include an emotionally withdrawn/inhibited pattern and a socially indiscriminate/disinhibited pattern. Assessment requires direct observation of the child in the context of his/her relationships with primary caregivers. Treatment requires establishing an attachment relationship for the child when none exists and ameliorating disturbed attachment relationships with caregivers when they are evident. Coercive treatments with children with attachment disorders are potentially dangerous and not recommended.