The interaction between perinatal factors and childhood abuse in the risk of developing anorexia nervosa.

BACKGROUND: Perinatal factors seem to be implicated in the pathogenesis of anorexia nervosa (AN) and may be involved in the programming of stress response systems in humans. Our aim was to explore one of the possible pathways to explain the association between perinatal complications and a psychiatric disorder. In particular, we tested the hypothesis that neonatal immaturity may confer an enhanced vulnerability to AN after exposure to a severe stressful event, such as childhood abuse. METHOD: The sample was composed of subjects who took part in a prevalence study carried out on a representative sample of the general population and cases of AN referred to an out-patient specialist unit. All subjects (n=663) were born in the two obstetric wards of Padua Hospital between 1971 and 1979. We analysed data using both a case-control and a cohort design. RESULTS: We found that functional signs of neonatal dysmaturity, but not a low birthweight or prematurity, had a significant additive interaction with childhood abuse in determining the risk for this illness. In normal subjects, but not in subjects with AN, neonatal dysmaturity was associated with being small, short or thin for gestational age at birth. CONCLUSIONS: The synergistic effect of neonatal dysmaturity and childhood abuse in increasing the risk for AN provides evidence for the hypothesis that a prenatal programming of stress response systems can result in an impairment of the individual's resilience to severe stressful events.