Attachment Disorder
Attachment issues and Reactive Attachment Disorder (RAD) has been subject of varying degrees of popularity which have hopefully served to educate people rather than label and disown the issue.
Children with attachment issues (which most of us have to a greater or lesser extent) can present challenging behaviour for their parents, though it is of course possible to work through this and manage the situation effectively. There has been a great deal written on this subject, so hopefully the links below will help clarify the current thinking around attachment.
Definition from Wikipedia:
Attachment disorder is a broad term intended to describe disorders of mood, behavior, and social relationships arising from a failure to form normal attachments to primary care giving figures in early childhood. Such a failure would result from unusual early experiences of neglect, abuse, abrupt separation from caregivers between 6 months and three years of age, frequent change or excessive numbers of caregivers, or lack of caregiver responsiveness to child communicative efforts resulting in a lack of basic trust. A problematic history of social relationships occurring after about age three may be distressing to a child, but does not result in attachment disorder.
Download the a OAASIS guidance on Attachment Disorder