background Animal research indicates that early maternal separation can permanently alter function of the hypothalamic-pituitary-adrenal axis (hpa-axis). Human data are scarce, and have been collected from selected clinical populations.
method We investigated the association between early maternal separation and the function of the hpa-axis (assessed by 24-hour urine cortisol levels on 2 consecutive days) in the salut population-cohort (N=1093; 46.1% male; average age 53.2, standard deviation (sd) 11.3).
results Of the study population, 124 participants indicated they had experienced maternal separation for at least 3 months before the age of 12. The average age at separation was 5.9 (sd 3.4) years. The following reasons for maternal separation were reported: parents divorced (n=8), mother died (n=10), mother hospitalized (n=32), participant hospitalized (n=18), participant adopted (n=50), other (n=2), unknown (n=4). Cortisol levels were significantly lower in participants with maternal separation than in those without maternal separation (mean cortisol 39.5 nM (sd 20.6) and 44.1 nM (sd 23.3), respectively; t=2.043, p=0.041). Subgroups were too small for subgroup differences to be analysed statistically. However, lower values were found in all subgroups, with the most pronounced effects being associated with maternal hospitalization and maternal death.
conclusion Maternal separation is associated with reduced urinary cortisol levels. Dysregulation of the hpa-axis could therefore be a mediating mechanism between early maternal separation and psychopathology.