Maternal stimulation in infancy predicts hypothalamic-pituitary-adrenal axis reactivity in young men.

Evidence from animal research has demonstrated the effect of early maternal care on the offspring's endocrine and behavioral stress response in adulthood. The present prospective study investigates, in humans, the long-term impact of maternal responsiveness and stimulation during early mother-child interaction on adrenocorticotropic hormone (ACTH) and cortisol response to a psychosocial laboratory stressor in adulthood. The data are from an epidemiological cohort study of the long-term outcome of early risk factors assessed at birth. At age 3 months, mothers and infants were videotaped during a 10-min standardized nursing and playing situation and evaluated by trained raters for maternal stimulation and infant and maternal responsiveness. At age 19 years, 270 participants (146 females, 124 males) completed the Trier Social Stress Test. The results indicated that less maternal stimulation during early interaction at age 3 months predicted diminished plasma ACTH and cortisol increase in response to acute psychosocial stress in male, but not female offspring. In contrast, maternal responsiveness was found to be unrelated to hypothalamic-pituitary-adrenal (HPA) reactivity. In accordance with the findings from animal research, the present study provides prospective evidence in humans of a long-term association between early maternal interaction behavior and the offspring's hormonal stress response in young adulthood, suggesting that poor maternal stimulation in early infancy may result in reduced HPA axis reactivity to an acute psychosocial stressor in males.