The effects of stress and stress hormones on human cognition: Implications for the field of brain and cognition

Abstract

In this review, we report on studies that have assessed the effects of exogenous and endogenous increases in stress hormones on human cognitive performance. We first describe the history of the studies on the effects of using exogenous stress hormones such as glucocorticoids as anti-inflammatory medications on human cognition and mental health. Here, we summarize the cases that led to the diagnosis of glucocorticoid-induced 'steroid psychosis' in human populations and which demonstrated that these stress hormones could thus cross the blood-brain barrier and access the brain where they could influence cognition and mental health. We then summarize studies that assessed the effects of the exogenous administration of glucocorticoids on cognitive performance supported by the hippocampus, the frontal lobes and amygdala. In the second section of the paper, we summarize the effects of the endogenous release of glucocorticoids induced by exposure to a stressful situation on human cognition and we further dissociate the effects of emotion from those of stress on human learning and memory. Finally, in the last section of the paper, we discuss the potential impact that the environmental context to which we expose participants when assessing their memory could have on their reactivity to stress and subsequent cognitive performance. In order to make our point, we discuss the field of memory and aging and we suggest that some of the 'age-related memory impairments' observed in the literature could be partly due to increased stress reactivity in older adults to the environmental context of testing. We also discuss the inverse negative correlations reported between hippocampal volume and memory for young and older adults and suggest that these inverse correlations could be partly due to the effects of contextual stress in young and older adults, as a function of age-related differences in hippocampal volume.

‘O’ blood type is associated with larger grey-matter volumes in the cerebellum

“…In this study 'A' adults were found to have a quicker recovery from the hormonal upregulation, but, at the same time, had also higher absolute levels of cortisol than 'O' adults at all stages of the experimental manipulation. Although the brain receptorial population for glucocorticoids is mainly located in mediotemporal/limbic and prefrontal areas (Lupien et al, 2007), no GM difference was visible in these regions between the two subgroups in Model 1 (which tested exactly the two blood types as in the study by Neumann and colleagues, 1992), suggesting that blood type probably does not regulate cerebellar GM volumes via a chronic effect of stresshormones. A fourth, endocrine route with a significant interaction with the cardiovascular system is that illustrated by the findings by Terao and colleagues (2013).…”

Steroid and nonsteroidal anti-inflammatory drugs, cognitive decline, and dementia

“…Cognitive assessment has principally focused on changes in declarative memory consistent with deficiencies in hippocampus-dependent activity, although recent studies have also noted impairments in prefrontal cortex processing (Wolkowitz et al, 2009;Lupien et al, 2007;Franz et al, 2011); both structures having a relatively high density of gluco-and mineralocorticoid receptors. These associations may be transient and dose-dependent (Newcomer et al, 1999;Kirschbaum et al, 1996;Young et al, 1999;de Quervain et al, 2003;Keenan et al, 1996).…”

“…Associations between short-term CS administration and cognitive impairment have been reported in small experimental and clinical studies in adults (Wolkowitz et al, 2009;Newcomer et al, 1999;Kirschbaum et al, 1996;Lupien et al, 2007;Young et al, 1999;de Quervain et al, 2003;Keenan et al, 1996). The effect of chronic CS administration has, however, never been examined in elderly populations who have high rates of both prescribed and over the counter drug use (Hilmer et al, 2007).…”

“…There is some evidence that corticosteroids (CS) could be associated with reversible cognitive dysfunction. ; both experimental and epidemiological research showing that dysregulation of the hypothalamic-pituitary-adrenal (HPA) corticotropic axis, a major component of the stress response system, may lead to, or accelerate hippocampal impairment (Belanoff et al, 2001;Conrad and Bimonte-Nelson, 2010;Lupien et al, 2007). This may be especially important in the ageing brain, more vulnerable to stress effects and subject to decrements in cognitive performance due to multiple causes.…”

Subjective Memory Complaints Are Associated with Diurnal Measures of Salivary Cortisol in Cognitively Intact Older Adults

“…Chronic stress in older adults can lead to dysfunction of the Hypothalamic-Pituitary-Adrenal (HPA) axis that regulates response to stress, subsequently affecting the hippocampus, a brain region critical for memory (4). …”