Archival ReportDaytime Cortisol Secretion in 6-Month-Old Twins: Genetic and Environmental Contributions as a Function of Early Familial Adversity
Section snippets
Participants
Participants were twins recruited between April 1995 and December 1998 in the greater Montréal area to participate in a longitudinal study. A total of 989 families were contacted, of which 672 agreed to participate (68%). Twins were first seen when they were 6 months of gestational age and then prospectively assessed on a variety of child and family characteristics. Informed consent was obtained from the parents annually. Interviews regarding environmental variables were generally conducted
Results
Table 1 presents the descriptive statistics of daytime cortisol samples according to pre-, peri- and postnatal variables. No significant differences were found at p < .05. Awakening cortisol was lower when sampled later [t(191) = −2.92, p = .003], perhaps because sleep routine often differs across infants, and parents were instructed to sample saliva when the child naturally awakes. No such difference was detected for the morning sample [t(201) = 1.31, p = .19]. The time of saliva collection
Discussion
The goal of this study was to examine the genetic and environmental contributions to morning cortisol secretion in 6-month-old twins and to determine whether these contributions varied according to FA. Genetic factors accounted for cortisol levels in different ways: a moderate “main effect” of genes was found for home-based awakening cortisol, whereas the contribution of genes to morning cortisol in the laboratory was conditional to FA. Specifically, in low FA settings (typical of most
References (92)
Allostasis and allostatic load: Implications for neuropsychopharmacology
Neuropsychopharmacology
(2000)- et al.
Diurnal salivary cortisol in pediatric posttraumatic stress disorder
Biol Psychiatry
(2002) Stress: A risk factor for serious illness
Metabolism
(2002)- et al.
Twenty-four-hour cortisol secretion patterns in prepubertal children with anxiety or depressive disorders
Biol Psychiatry
(2004) The neurobiology of stress: From serendipity to clinical relevance
Brain Res
(2000)- et al.
The hormonal costs of subtle forms of infant maltreatment
Horm Behav
(2003) - et al.
Hyperresponsiveness of hypothalamic-pituitary-adrenal axis to combined dexamethasone/corticotropin-releasing hormone challenge in female borderline personality disorder subjects with a history of sustained childhood abuse
Biol Psychiatry
(2002) - et al.
Do early-life events permanently alter behavioral and hormonal responses to stressors?
Int J Dev Neurosci
(1998) - et al.
Hormonal and behavioral homeostasis in boys at risk for substance abuse
Drug Alcohol Depend
(1999) - et al.
The potential role of hypocortisolism in the pathophysiology of stress-related bodily disorders
Psychoneuroendocrinology
(2000)