Low cortisol and a flattening of expected daytime rhythm: Potential indices of risk in human development

Abstract

Since the work of Hans Selye, stress has been associated with increased activity of the limbic–hypothalamic– pituitary–adrenocortical (LHPA) axis. Recently, a number of studies in adults have shown that this neuroendocrine axis may be hyporesponsive in a number of stress-related states. Termed hypocortisolism, the paradoxical suppression of the LHPA axis under conditions of trauma and prolonged stress presently challenges basic concepts in stress research. Adverse conditions that produce elevated cortisol levels early in life are hypothesized to contribute to the development of hypocortisolism in adulthood. However, as reviewed in this paper, hypocortisolism also may be a common phenomenon early in human childhood. Although preliminary at this point, the ubiquity of these findings is striking. We argue that developmental studies are needed that help explicate the origins of low cortisol and to determine whether the development of hypocortisolism is, in fact, preceded by periods of frequent or chronic activation of the LHPA axis. We also argue that developmental researchers who incorporate measures of salivary cortisol into their studies of at-risk populations need to be aware of the hypocortisolism phenomenon. Lower than expected cortisol values should not necessarily be relegated to the file drawer because they contradict the central dogma that stress must be associated with elevations in cortisol. Lastly, we note that evidence of low cortisol under adverse early life conditions in humans adds to the importance of understanding the implications of hypocortisolism for health and development.

Environmental enrichment in early life affects cortisol patterns in growing pigs

“…A circadian rhythm of cortisol was defined as a sufficient decline in the saliva concentration from morning to afternoon and evening (Santiago et al, 1996). Absence of the expected morning surge, leaving a flat basal secretion pattern, is, in man, associated with severe or prolonged stress and certain psychopathologic states (review by Gunnar and Vazquez, 2001). In pigs, such blunted cortisol curves have been reported in conditions associated with behavioural signs of stress, that is, tethering (Barnett et al, 1987;Janssens et al, 1995) and crowded housing without substrate (de Jong et al, 1998 and.…”

Salivary cortisol and heart rate in stunted and nonstunted Nepalese school children

“…However, in another study based in Jamaica, stunted children had levels of cortisol similar to nonstunted children but higher heart rates, and there was also a tendency for the stunted children to have blunted responsivity (Fernald & Grantham-McGregor, 2002). The flattening of cortisol responsivity has been reported in children living under adverse circumstances (Gunnar & Vasquez, 2001). Blunted cortisol responsivity, sometimes accompanied by low daytime values, has been termed 'hypocortisolism', and has been reported under conditions of trauma and prolonged stress (Heim et al, 2000).…”

Coping with Social Stress: Implications for Psychopathology in Young Adolescent Girls

“…Following the onset of a stressor, it usually takes about 10-15 min to produce a rise in circulating cortisol levels; about 20-30 min after the stressor, peak concentrations of cortisol are found in saliva (Klimes-Dougan et al 2001). Following this peak, the negative feedback loop of the LHPA axis begins to reestablish homeostatic functioning by reducing the level of circulating cortisol (Gunnar and Vazquez 2001).…”

“…Recent research examining responses to social challenges (i.e., public speaking tasks, parent-child conflict discussion tasks, or peer-rejection simulations) has shown that adolescents and children who maintained high levels of cortisol or displayed strong task-related decreases demonstrated greater levels of internalizing and externalizing behavior (Granger et al 1994;Klimes-Dougan et al 2001;Schmidt et al 1999). Although these studies have focused exclusively on cortisol reactivity in response to a specific task, other studies have found that chronic activation of the L-HPA system from continued exposure to stress may alter an individual's reactivity profile, increasing the likelihood of experiencing hypo-or hypersecretion in response to future stressors (Gunnar and Vazquez 2001;Kendall-Tackett 2000). Exposure to stress again (e.g.…”