The allostatic load model expands the stress-disease literature by proposing a temporal cascade of multi-systemic physiological dysregulations that contribute to disease trajectories. By ...incorporating an allostatic load index representing neuroendocrine, immune, metabolic, and cardiovascular system functioning, numerous studies have demonstrated greater prediction of morbidity and mortality over and beyond traditional detection methods employed in biomedical practice. This article reviews theoretical and empirical work using the allostatic load model vis-à-vis the effects of chronic stress on physical and mental health. Specific risk and protective factors associated with increased allostatic load are elucidated and policies for promoting successful aging are proposed.
•Chronic exposure to high levels of glucocorticoids have neurotoxic effects on the brain.•Exposure to early adversity increases vulnerability to stress in some individuals.•Early interventions modify ...the physiological stress response in vulnerable individuals.
For the last five decades, science has managed to delineate the mechanisms by which stress hormones can impact on the human brain. Receptors for glucocorticoids are found in the hippocampus, amygdala and frontal cortex, three brain regions involved in memory processing and emotional regulation. Studies have shown that chronic exposure to stress is associated with reduced volume of the hippocampus and that chronic stress can modulate volumes of both the amygdala and frontal cortex, suggesting neurotoxic effects of stress hormones on the brain. Yet, other studies report that exposure to early adversity and/or familial/social stressors can increase vulnerability to stress in adulthood. Models have been recently developed to describe the roles that neurotoxic and vulnerability effects can have on the developing brain. These models suggest that developing early stress interventions could potentially counteract the effects of chronic stress on the brain and results going along with this hypothesis are summarized.
Highlights • Obtaining meaningful data of the CAR requires attention to methodological detail. • The ISPNE initiated an expert panel to establish quality standards of CAR assessment. • The results of ...this initiative are summarized. • Detailed methodological considerations are outlined and discussed. • Agreed consensus guidelines are presented.
Chronic exposure to stress hormones, whether it occurs during the prenatal period, infancy, childhood, adolescence, adulthood or aging, has an impact on brain structures involved in cognition and ...mental health. However, the specific effects on the brain, behaviour and cognition emerge as a function of the timing and the duration of the exposure, and some also depend on the interaction between gene effects and previous exposure to environmental adversity. Advances in animal and human studies have made it possible to synthesize these findings, and in this Review a model is developed to explain why different disorders emerge in individuals exposed to stress at different times in their lives.
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DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
► Chronic stress impacts cognition and increases vulnerability to mental illness. ► Findings have first emerged from the field of healthy and pathological aging. ► Other mental health problems in ...younger populations are also chronic stress models. ► There are individual differences regarding stress, cognition and mental health. ► Individual factors must be considered to understand the impact of chronic stress.
This review aims to discuss the evidence supporting the link between chronic stress, cognitive function and mental health. Over the years, the associations between these concepts have been investigated in different populations. This review summarizes the findings that have emerged from older populations as well as from populations suffering from pathological aging, namely Mild Cognitive Impairment and Alzheimer’s Disease. Although older adults are an interesting population to study in terms of chronic stress, other stress-related diseases can occur throughout the lifespan. The second section covers some of these stress-related diseases that have recently received a great deal of attention, namely burnout, depression, and post-traumatic stress disorder. Given that chronic stress contributes to the development of certain pathologies by accelerating and/or exacerbating pre-existing vulnerabilities that vary from one individual to the other, the final section summarizes data obtained on potential variables contributing to the association between chronic stress and cognition.
Lesbian, gay, and bisexual (LGB) individuals-particularly those who have not disclosed their sexual orientation-are believed to experience increased chronic stress in comparison with heterosexuals. ...This interdisciplinary study assessed whether psychiatric symptoms (self-rated anxiety, depression, and burnout), stress hormone profiles (diurnal cortisol), and physiological dysregulations (allostatic load AL) would differ for a) LGBs versus heterosexuals and b) disclosed LGBs versus nondisclosed LGBs.
The study included 87 healthy participants (mean SD age=24.6 0.6 years; LGB n=46, 43% women; and heterosexual n=41, 49% women). Diurnal cortisol sampled at five time points was averaged for 2 days. AL indices were based on an algorithm incorporating 21 biomarkers representing neuroendocrine, immune/inflammatory, metabolic, and cardiovascular functioning. Psychological measures were assessed with well-validated questionnaires.
Between-group results revealed no significant differences in symptoms of anxiety and burnout, nor among diurnal cortisol levels between sexual orientations. By contrast, gay/bisexual men unexpectedly had lower depressive symptoms (p=.003) and AL levels (p=.043) compared with heterosexual men. Within-group results revealed that disclosed LGBs had fewer psychiatric symptoms (p values<0.01) and lower cortisol levels +30 minutes upon awakening (p=.004) compared with nondisclosed LGBs. Disclosure was not significantly related to AL levels.
LGBs did not manifest more stress-related problems than did heterosexuals. Life transitions like disclosing to one's family and friends may be protective against psychopathologies and hyperactive cortisol awakening responses. Our novel findings underline the roles disclosure processes have on positive health and well-being for sexual minorities.
Maternal separation and poor maternal care in animals have been shown to have important effects on the developing hippocampus and amygdala. In humans, children exposed to abuse/maltreatment or ...orphanage rearing do not present changes in hippocampal volumes. However, children reared in orphanages present enlarged amygdala volumes, suggesting that the amygdala may be particularly sensitive to severely disturbed (i.e., discontinous, neglectful) care in infancy. Maternal depressive symptomatology has been associated with reductions in overall sensitivity to the infant, and with an increased rate of withdrawn, disengaged behaviors. To determine if poor maternal care associated with maternal depressive symptomatology has a similar pattern of association to the volumes of the hippocampus and amygdala in children, as is the case for severely disturbed infant care (orphanage rearing), we measured hippocampal and amygdala volumes as well as stress hormone (glucocorticoid) levels in children exposed (n = 17) or not (n = 21) to maternal depressive symptomatology since birth. Results revealed no group difference in hippocampal volumes, but larger left and right amygdala volumes and increased levels of glucocorticoids in the children of mothers presenting depressive symptomatology since birth. Moreover, a significant positive correlation was observed between mothers' mean depressive scores and amygdala volumes in their children. The results of this study suggest that amygdala volume in human children may represent an early marker of biological sensitivity to quality of maternal care.
Recent theories have suggested that chronic pain could be partly maintained by maladaptive physiological responses of the organism facing a recurrent stressor. The present study examined the ...associations between basal levels of cortisol collected over seven consecutive days, the hippocampal volumes and brain activation to thermal stimulations administered in 16 patients with chronic back pain and 18 healthy control subjects. Results showed that patients with chronic back pain have higher levels of cortisol than control subjects. In these patients, higher cortisol was associated with smaller hippocampal volume and stronger pain-evoked activity in the anterior parahippocampal gyrus, a region involved in anticipatory anxiety and associative learning. Importantly, path modelling--a statistical approach used to examine the empirical validity of propositions grounded on previous literature--revealed that the cortisol levels and phasic pain responses in the parahippocampal gyrus mediated a negative association between the hippocampal volume and the chronic pain intensity. These findings support a stress model of chronic pain suggesting that the sustained endocrine stress response observed in individuals with a smaller hippocampii induces changes in the function of the hippocampal complex that may contribute to the persistent pain states.
•Healthy adults first exposed to early adversity between the ages of 3 and 7 – an important time window for amygdala development – show greater cortisol awakening response relative to those first ...exposed to EA before 3 or after 7.•Healthy adults first exposed to early adversity between the ages of 3 and 7 show blunted cortisol reactivity relative to those first exposed to EA before 3 or after 7.•Minimal age at exposure to early adversity better predicts basal and reactive cortisol levels as opposed to the classical accumulation model of early adversity.
Early adversity (EA) modulates stress hormone secretion in mixed directions. The Accumulation Model suggests that the number of EA predicts patterns of cortisol dysregulations, while the Life Cycle Model of Stress highlights the importance of considering the timing at which EA began, given that brain regions sensitive to stress hormones follow distinct developmental trajectories. We aimed to test these two models in 85 healthy men and women, aged 21–40 years old who reported having been exposed to EA during childhood. Participants were grouped based on the number of EA events to which they were exposed during their lifespan (Accumulation Model) and the age of first exposure to EA (Life Cycle Model). Diurnal and stress-induced reactive cortisol secretion were measured in all participants. Results showed that although the number of EA was not associated with patterns of basal or reactive cortisol secretion, adults first exposed to EA between the ages of 3 and 7 – an important time window for amygdala development – showed greater cortisol awakening response and lower cortisol reactivity relative to those first exposed to EA before 3 or after 7. These results provide support for the Life Cycle Model of Stress and highlight the importance of considering minimal age at exposure to EA when assessing the effects of early adversity on patterns of cortisol secretion.
The cortisol awakening response (CAR) is frequently assessed in psychobiological (stress) research. Obtaining reliable CAR data, however, requires careful attention to methodological detail. To ...promote best practice, expert consensus guidelines on the assessment of the CAR were published (Stalder et al., 2016, PNEC). However, it is unclear whether these highly cited guidelines have resulted in actual methodological improvements. To explore this, the PNEC editorial board invited the present authors to conduct a critical evaluation and update of current CAR methodology, which is reported here. (i) A quantitative evaluation of methodological quality of CAR research published in PNEC before and after the guidelines (2013–2015 vs. 2018–2020) was conducted. Disappointingly, results reveal little improvement in the implementation of central recommendations (especially objective time verification) in recent research. (ii) To enable an update of guidelines, evidence on recent developments in CAR assessment is reviewed, which mostly confirms the accuracy of the majority of the original guidelines. Moreover, recent technological advances, particularly regarding methods for the verification of awakening and sampling times, have emerged and may help to reduce costs in future research. (iii) To aid researchers and increase accessibility, an updated and streamlined version of the CAR consensus guidelines is presented. (iv) Finally, the response of the PNEC editorial board to the present results is described: potential authors of future CAR research to be published in PNEC will be required to submit a methodological checklist (based on the current guidelines) alongside their article. This will increase transparency and enable reviewers to readily assess the quality of the respective CAR data. Combined, it is hoped that these steps will assist researchers and reviewers in assuring higher quality CAR assessments in future research, thus yielding more reliable and reproducible results and helping to further advance this field of study.
•CAR assessment guidelines published in 2016, but unknown if followed by research.•Quantitative evaluation results: Main guidelines are still not consistently followed.•Evidence of recent developments in CAR methodology is reviewed.•Updated CAR consensus guidelines are presented.•Future CAR submissions to PNEC have to fill in checklist based on guidelines.
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