I'm not sure "attachment disorder" is a useful classification, but it's popular in the special needs and adoption worlds. Whatever the fundamental pathophysiology, I wonder how long it will be before we start seeing therapeutic trials using oxytocin nasal spray. It will be a long time, however, before such a treatment would get FDA approval...
The hormone, oxytocin, produced during childbirth and lactation - encourages us to trust strangers, it is also a hormone which gets mammals to mate. Swiss researchers have found that when people are given some of this hormone they trust people who are handling their money much more.