(1) Centre for Studies on Human Stress, Research Centre of the Mental Health University Institute, Louis-H Lafontaine Hospital, Montreal, Quebec, Canada
(2) School of Psychoeducation, University of Montreal, Montreal, Quebec, Canada
*Corresponding author Email: firstname.lastname@example.org
Environmental contaminants are ubiquitous. Among the most studied environmental contaminants, lead, mercury, polychlorinated biphenyls and pesticides have been found to impact mental health. In particular, exposure to environmentalcontaminants has been related to executive functions and emotional/behavioural maladjustment in children, and cognitive variability in elders. We hypothesise that the association between environmental contaminants and mental health, particularly in children and elders, could be explained by a disruption of the stress system.
Environmental contaminants act at very low levels of exposure that are not reflected by high doses. Therefore, public regulation agencies are consistently reducing acceptable blood levels of exposure. For example, clinical management plans for children and elders at risk of toxicity are thus adapted to reflect the novel blood lead action level. Environmental contaminants acting at such low doses were found to be endocrine-disrupting chemicals, and most studies have thus focused on the sexual steroids system. However, the stress system, which produces glucocorticoids, has been overlooked. Glucocorticoids are able to cross the blood–brain barrier and reach the central structure involved in cognitive functions and emotional/behavioural regulation. Furthermore, studies have revealed that environmental contaminants significantly influence the stress system across a variety of wildlife animals, laboratory animals and recently in humans.
The hypothesis of the stress system, linking environmental contaminant exposure to adverse mental health effects, needsto be addressed in future research. In addition, in cases of environmental contaminants toxicity, clinicians could recommend the testing of the hypothalamic–pituitary–adrenal axis functioning in order to prevent children and/or the elderly to develop impairments due to its alteration.