Attachment refers to the way in which children bond with their primary caregiver - usually their mother - and is thought to affect the way children develop and form relationships later in life. One of the ways in which psychologists assess children's 'attachment style' is by seeing how they react when their mothers leave the room. Children with secure attachment can tolerate brief separations and are easily comforted when their mothers return. Children with insecure attachment react differently; they may snub the returning caregiver or go to them but resist being picked up. A small group of children exhibit disorganized attachment. When they are reunited with their caregivers they can look dazed or frightened, freeze in place, back towards the caregiver or approach with their head sharply averted. Disorganized attachment is seen as a major risk factor for childhood mental-health problems and aggressive behaviour. Researchers in Germany and Hungary looked into the links between genes, upbringing and disorganized attachment in a sample of 106 one-year-olds. They found that there was a significant association between disorganized attachment and a variation in a gene called DRD4. However, this genetic link was only activated in children whose mothers showed low responsiveness to them.
Spangler, Gottfried ... [et al] - Genetic and environmental influence on attachment disorganization Journal of Child Psychology and Psychiatry August 2009, 50(8), 952-961