Possible Mechanisms
One study has reported a connection between a specific genetic marker and disorganized attachment (not RAD) associated with problems of parenting. Another author has compared atypical social behavior in genetic conditions such as Williams syndrome with behaviors symptomatic of RAD.
Typical attachment development begins with unlearned infant reactions to social signals from caregivers. The ability to send and receive social communications through facial expressions, gestures and voice develops with social experience by seven to nine months. This makes it possible for an infant to interpret messages of calm or alarm from face or voice. At about eight months, infants typically begin to respond with fear to unfamiliar or startling situations, and to look to the faces of familiar caregivers for information that either justifies or soothes their fear. This developmental combination of social skills and the emergence of fear reactions results in attachment behavior such as proximity-seeking, if a familiar, sensitive, responsive, and cooperative adult is available. Further developments in attachment, such as negotiation of separation in the toddler and preschool period, depend on factors such as the caregiver's interaction style and ability to understand the child's emotional communications.
With insensitive or unresponsive caregivers, or frequent changes, an infant may have few experiences that encourage proximity seeking to a familiar person. An infant who experiences fear but who cannot find comforting information in an adult's face and voice may develop atypical ways of coping with fearfulness such as the maintenance of distance from adults, or the seeking of proximity to all adults. These symptoms accord with the DSM criteria for reactive attachment disorder. Either of these behavior patterns may create a developmental trajectory leading ever farther from typical attachment processes such as the development of an internal working model of social relationships that facilitates both the giving and the receiving of care from others.
Atypical development of fearfulness, with a constitutional tendency either to excessive or inadequate fear reactions, might be necessary before an infant is vulnerable to the effects of poor attachment experiences.
Alternatively, the two variations of RAD may develop from the same inability to develop "stranger-wariness" due to inadequate care. Appropriate fear responses may only be able to develop after an infant has first begun to form a selective attachment. An infant who is not in a position do this cannot afford not to show interest in any person as they may be potential attachment figures. Faced with a swift succession of carers the child may have no opportunity to form a selective attachment until the possible biological-determined sensitive period for developing stranger-wariness has passed. It is thought this process may lead to the disinhibited form.
In the inhibited form infants behave as if their attachment system has been "switched off". However the innate capacity for attachment behavior cannot be lost. This may explain why children diagnosed with the inhibited form of RAD from institutions almost invariably go on to show formation of attachment behavior to good carers. However children who suffer the inhibited form as a consequence of neglect and frequent changes of caregiver continue to show the inhibited form for far longer when placed in families.
Additionally, the development of Theory of Mind may play a role in emotional development. Theory of Mind is the ability to know that the experience of knowledge and intention lies behind human actions such as facial expressions. Although it is reported that very young infants respond differently to humans and objects, Theory of Mind develops relatively gradually and possibly results from predictable interactions with adults. However, some ability of this kind must be in place before mutual communication through gaze or other gesture can occur, as it does by seven to nine months. Some neurodevelopmental disorders, such as autism, have been attributed to the absence of the mental functions that underlie Theory of Mind. It is possible that the congenital absence of this ability, or the lack of experiences with caregivers who communicate in a predictable fashion, could underlie the development of reactive attachment disorder.
Read more about this topic: Attachment Disorder