This article in the Albuquerque Tribune lays out the causes, symptoms and treatments for reactive attachment disorder in a nice, clear way. According to Scott Blackwell, a psychologist and consultant at Villa Santa Maria, a residential treatment center specializing in treating attachment-resistant children:
The mother's neurological function is effectively being downloaded into the child's brain. If this doesn't occur, these kids can struggle with concentration, emotional regulation and other developmental issues. They can become very upset and have difficulty coping or soothing themselves.
Without a safe, secure bond to a consistent caretaker, these kids can't establish the proper neurological pathways to the brain's reasoning center, so it's hard for them to cope when they get upset. Attachment disorder can present with symptoms of attention deficit hyperactive disorder, bipolar disorder, post-traumatic stress disorder and others.
Blackwell says dyadic developmental psychotherapy can be helpful. This new treatment involves experiences that form a bond with the therapist; by contrast,nmany other therapies work through the relationship between therapist and child. But RAD kids can't form that relationship.