Minnis, Helen and Reekie, Joanne and Young, David and O'Connor, Tom and Ronald, Angelica and Gray, Alison and Plomin, Robert (2007) Genetic, environmental and gender influences on attachment disorder behaviours. British Journal of Psychiatry, 190. pp. 490-495. ISSN 0007-1250
Background Despite current interest in attachment disorder, there is concern about its discrimination from other disorders and an unproven assumption of an environmental aetiology. Aims To test whether behaviours suggestive of attachment disorder are distinct from other childhood behavioural and emotional problems and are solely environmentally determined. Method In a community sample of 13 472 twins, we carried out factor analysis of questionnaire items encompassing behaviours indicative of attachment disorder, conduct problems, hyperactivity and emotional difficulties. We used behavioural genetic model-fitting analysis to explore the contribution of genes and environment. Results Factor analysis showed clear discrimination between behaviours suggestive of attachment disorder, conduct problems, hyperactivity and emotional problems. Behavioural genetics analysis suggested a strong genetic influence to attachment disorder behaviour, with males showing higher heritability. Conclusions Behaviours suggestive of attachment disorder can be differentiated from common childhood emotional and behavioural problems and appear to be strongly genetically influenced, particularly in boys. INTRODUCTION TOP ABSTRACT INTRODUCTION METHOD RESULTS DISCUSSION REFERENCES There have been recent attempts to codify behaviours associated with early neglect and institutionalisation (Chisolm et al, 1995; Zeanah et al, 2004) into a psychiatric category. Both DSM–IV and ICD–10 describe reactive attachment disorder, with two subtypes encompassing inhibited and disinhibited behaviour (World Health Organization, 1992; American Psychiatric Association, 1994). Questions remain about the nosology of the syndrome beyond age 5 years (American Academy of Child and Adolescent Psychiatry, 2005), therefore we simply refer to ‘attachment disorder behaviours’. We seek to extend the extant literature by testing two hypotheses: first, that the two subtypes are distinct from one another and from other common behavioural and emotional problems in young children, and second that these behavioural patterns are environmentally mediated. We capitalise on a twin study, a design that provides particular leverage in testing environmental hypotheses.
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