What is the definition or description of: reactive attachment disorder?

RAD: Markedly disturbed & developmentally inappropriate ways of relating socially to others. It arises from failure to form failure to form normal attachments to primary caregivers in early childhood, due to neglect or abuse or abrupt separation or frequent change of caregivers at age 6months to 3 years. It can be inhibited form (avoid comfort) or disinhibited (excessive indiscriminate seeking of atten.