Since it is believed that a strong attachment provides the basis for healthy emotional and social development, children who are deprived of the opportunity to form attachments, due to deprived environments and/or grossly inadequate caregiving, may develop a Reactive Attachment Disorder. Although epidemiological data are limited, the disorder is uncommon. Because of its association with other disorders it may be underdiagnosed.

According to the Diagnostic and Statistical Manual of Mental Disorders IV (DSM-IV) a child must show markedly disturbed and developmentally inappropriate social relatedness in most contexts, beginning before age 5, as shown by either a) persistent failure to initiate or respond to most social interactions, excessively inhibited, hypervigilant or ambivalent and contradictory responses, or b) indiscriminate sociability or inability to exhibit appropriate selective attachments. Neglectful care can be shown by at least one of the following: disregard for the child's emotional needs for stimulation, comfort and affection; disregard of child’s physical needs, or repeated changes of primary caregiver.