Early-Life Stress: From Neuroendocrine Mechanisms to Stress-Related Disorders

Abstract

Stress exposure is highly prevalent in the general population; however, the experience of stress during vulnerable periods of development has substantial and permanent effects on brain structure and function and physical health in adulthood. Stress, the state of threatened homeostasis, is generally associated with a time-limited activation of the stress system, i.e., the hypothalamic-pituitary-adrenal axis and the arousal/sympathetic nervous system, tailored to the stressful stimulus also known as the stressor. On the other hand, chronic stress may be associated with lingering hyper- or hyposecretion of mediators of the stress system. This chronic condition is called dyshomeostasis, allostasis, or cacostasis and is associated with increased mental and physical morbidity in the long term. Stressful or traumatic experiences during fetal life, early childhood, and adolescence have been related to persistent neuroendocrine and epigenetic changes. Further, brain structures involved in the stress response, such as those of the stress system, the hippocampus, and the amygdala, may be programmed early on for a life of adversity.

Sex differences in hypothalamic–pituitary–adrenal axis regulation after chronic unpredictable stress

“…Epidemiological data reveal sex differences in several affective disorders that are exacerbated by stress (Bangasser & Valentino, 2014). Many studies have examined how chronic stress contributes to the etiology of psychiatric disorders such as anxiety and depression (Bremne & Vermetten, 2001; McEwen, 2017; Pervanidou & Chrousos, 2018). The sex differences in disease prevalence suggests the underlying differences in stress‐related pathogenesis.…”

Giving Children a Voice in Court?

“…122 With regard to brain development, research has shown that (chronic) exposure to stress in early childhood has adverse effects on the development of various brain areas, including the amygdala and hippocampus. 123 These areas remained poorer connected and were associated with poorer memory and more internalising behaviour. 124 As mentioned earlier, children are sensitive to acceptance and rejection.…”

The Brain Stress Systems I: The Implicit Level of Brain Operations

“…Activation of the brain into defensive mode occurs in tandem with activation of the stress system as a whole. The brain secretes neurotransmitters (the brain's messenger molecules), including noradrenalin in the locus coeruleus (in the brain stem) and corticotropin-releasing hormone (CRH) in the hypothalamus, to facilitate processing in the brain, to change the pattern of neural activation and connectivity, and to activate the broader stress system (Chrousos and Gold 1998;Pervanidou and Chrousos 2018;Arnsten 2015). At the same time, the HPA axis is switched on (via the hypothalamus) to mobilize energy resources throughout the body (see Chapter 8); the sympathetic system is switched on (via the brain's autonomic centres) to increase arousal in the body (see Chapter 6); and the immune-inflammatory system is switched on (via immune-inflammatory cells that reside in the brain) to work with neurons to support the brain's response to stress (see Chapter 9).…”