Attachment disorder refers to disturbances in social relationships attributable to a failure to form normal attachments to a primary carer, usually a mother, in infancy. The major classification systems ICD-10 and DSM-IV distinguish between reactive attachment disorders or RAD and disinhibited attachment disorder, or DAD, although categories tend to overlap and diagnostic criteria are not agreed. RAD is characterized by a reluctance to initiate or respond appropriately to social interactions. DAD is characterized by attention-seeking and indiscriminately friendly behavior.