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Beyond bad parenting
Attachment disorganization in infants is associated with a form of the DRD4 gene
Edward R. Winstead

Since the 1970s, researchers have studied parent-child bonding, or attachment, by observing infants in the 'strange situation' room. During the experiment, an infant lying in an unfamiliar room receives periodic visits from a parent or a stranger, and researchers analyze and evaluate the interactions. Infants with 'secure' attachment tend to seek contact and may greet a parent from a distance with a smile or a wave. Infants with 'disorganized' attachment, on the other hand, appear disoriented during interactions or behave in a manner that suggests anxiety.

Nearly 80 studies suggest the validity of disorganized attachment

Disorganized attachment may be a predictor of social or adjustment problems later in life. Most explanations for a child's failure to develop bonds say that the parent is somehow to blame. In recent years, however, researchers have begun to consider biological risk factors involving the child, such as neurological impairments. A new study reports an association between attachment disorganization and a version of the dopamine D4 receptor gene in a Hungarian population. The DRD4 gene comes in different forms. One common polymorphism is a sequence of 48 letters that is repeated throughout the population at different lengths.

Researchers at Semmelweis University, in Budapest, investigated a link between the 7-repeat variant and attachment disorganization in 90 one-year-old infants. They found that infants in the study with disorganized attachment were significantly more likely than other infants to have the 7-repeat variant of DRD4. The research is part of the longitudinal Budapest Infant Parent Study (BIPS), which tracks early development. The 90 infants in the current study were not considered at risk for attachment disorganization.

"The finding of our study suggests a genetic contribution to attachment disorganization in the non-clinical BIPS sample," the researchers write in the current issue of Molecular Psychiatry. They conclude: "The presence of this allele, we postulate, is one of the child factors underlying the disorganization of attachment behavior in low-risk, non-clinical populations."

Dopamine plays a role in attentiveness and activity, and the 7-repeat motif in DRD4 is a risk factor for behavioral problems in children.

Last year, researchers in the Netherlands analyzed ten years of data on attachment disorganization from nearly 80 published studies. The analyses, they concluded, "have established the reliability and discriminant validity of disorganized infant attachment. Although disorganized attachment behavior is necessarily difficult to observe and often subtle, many researchers have managed to become reliable coders."

The Strange Situation test is a standard procedure during attachment testing. The test was developed in the late 1970s by Mary D. Salter Ainsworth, then a researcher at the University of Virginia.

See related GNN article
»The DRD4 Gene: Psychiatry's Repeat Offender

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Lakatos, K. et al. Dopamine D4 receptor (DRD4) gene polymorphism is associated with attachment disorganization in infants. Mol Psychiatry 5, 633-637 (November 2000).

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