Polymorphism of the 5-HT2A Receptor Gene: Association with Stress-Related Indices in Healthy Middle-Aged Adults

Past research has concentrated on the stress system and personality in order to explain the variance found in cognitive performance in old age. A growing body of research is starting to focus on genetic polymorphism as an individual difference factor to explain the observed heterogeneity in cognitive function. While the functional mechanism is still under investigation, polymorphism of the 5-HT2A receptor gene (−1438A/G) has been linked to certain behavioral and physiological outcomes, including cortisol secretion, the expression of certain personality traits, and memory performance. It was the goal of the present study to investigate the association between the −1438A/G polymorphism and stress hormone secretion, stress-related psychological measures, and cognitive performance in a group of adults between the ages of 50 and 65. To examine these associations, 101 middle-aged adults were recruited, completed a battery of psychological questionnaires and were administered a battery of cognitive tasks that assess frontal lobe and hippocampal function. Basal and stress-reactive salivary cortisol levels were collected, at home and in the laboratory. Analyses on psychological measures showed that participants with the GG genotype reported significantly higher levels of neuroticism compared to the AG group and higher levels of depression and more emotion-based coping strategies compared to both the AG and AA group. In terms of cortisol secretion, the AA genotype was related to a significantly higher awakening cortisol response (ACR) compared to the AG and GG group and the GG genotype group displayed a greater increase in cortisol secretion following a psychosocial stressor compared to the two other groups. On measures of cognitive performance, the AA genotype group performed significantly better on a test of declarative memory and selective attention compared to the other two groups. Together, these results suggest that carriers of the GG genotype are more susceptible to low mood and display a greater potential for an overactive stress system, which may influence cognitive function in later years

Toxoplasma gondii infection in people with schizophrenia is related to higher hair glucocorticoid levels

IntroductionToxoplasma gondii (TG) is a common protozoan parasite infecting approximately one third of the human population. Animal studies have shown that this parasite can manipulate its host behavior. Based on this, human studies have assessed if TG can be involved in mental health disorders associated with important behavioral modifications such as schizophrenia. However, results have been discrepant. Given that TG has a strong impact on fear and risk-taking processes in animal studies and that fear and risk-taking behaviors are associated with the human stress response, we tested whether glucocorticoid biomarkers (salivary and hair) differ in people with schizophrenia and controls as a function of TG status. MethodsWe measured TG antibodies in blood samples, as well as salivary and hair glucocorticoid levels in 226 people with schizophrenia (19.9% women, mean age = 39 years old) and 129 healthy individuals (controls) (45.7% women, mean age = 41 years old). ResultsThe results showed that people with schizophrenia infected with TG presented significantly higher hair glucocorticoid concentrations than non-infected people with schizophrenia. This effect was not found in control participants. No effect was observed for salivary glucocorticoid levels. Additionally, there were no associations between TG infection and positive psychotic symptoms nor impulsivity. DiscussionThese results show that people with schizophrenia present high levels of hair glucocorticoid levels only when they are infected with TG. Further studies performed in populations suffering from other mental health disorders are needed to determine if this effect is specific to schizophrenia, or whether it is generalized across mental health disorders

Cross-Country Differences in Basal and Stress-Induced Cortisol Secretion in Older Adults

Objectives: Several studies have emphasized the association between socioeconomic status (SES) and inadequate response of the biological stress system. However, other factors related to SES are rarely considered, such as cultural values, social norms, organization, language and communication skills, which raises the need to investigate cross-country differences in stress response. Although some studies have shown differences in cortisol levels between immigrants and natives, there is no cross-country evidence regarding cortisol levels in country-native elders. This is particularly important given the high prevalence of stress-related disorders across nations during aging. the current study examined basal diurnal and reactive cortisol levels in healthy older adults living in two different countries.Methods: Salivary cortisol of 260 older adults from Canada and Brazil were nalyzed. Diurnal cortisol was measured in saliva samples collected at home throughout two working days at awakening, 30 min after waking, 1400 h, 1600 h and before bedtime. Cortisol reactivity was assessed in response to the Trier Social Stress Test (TSST) in both populations.Results: Our results showed that even under similar health status, psychological and cognitive characteristics, Brazilian elders exhibited higher basal and stress-induced cortisol secretion compared to the Canadian participants.Conclusion: These findings suggest that country context may modulate cortisol secretion and could impact the population health.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)CIHRAlzheimer's Society of CanadaUniv São Paulo, Dept Med Surg Nursing, Sch Nursing, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Psychobiol, São Paulo, BrazilUniv Montreal, Sch Psychoeduc, Montreal, PQ, CanadaUniv Montreal, Dept Psychiat, Ctr Studies Human Stress, Mental Hlth Inst,Montreal Res Ctr, Montreal, PQ H3C 3J7, CanadaRyerson Univ, Dept Psychol, Toronto, ON, CanadaUniversidade Federal de São Paulo, Dept Psychobiol, São Paulo, BrazilFAPESP: 2009/13911-6CIHR: 165618CIHR: 232974Web of Scienc

The Adolescent Brain : A second window to opportunity

Scientific advances over the past decade have contributed to a much greater understanding of the growth of the human brain from birth to adulthood. Latest evidence illuminates the adolescent brain as a ‘work in progress’, and adolescence as a critical period to build on early investments, offering a second chance for those who have not fared well in early childhood. Neuroscientific research in particular is integral to improving our understanding of the cerebral transformations that take place during this time and how they are influenced by interactions between the evolving adolescent brain and the environment in which it develops. In the field of early childhood development (ECD), neuroscientific evidence featured prominently in galvanizing positive change for children through changes in policy and programming and more of this type of evidence is needed to also provide answers regarding critical intervention junctures and approaches during adolescence. In this compendium, eight experts in adolescent neuroscience and development summarize scientific and programmatic evidence from their work, offering an insight into how to maximize the potential of adolescents during this period of opportunity, but also vulnerability. It builds on the discussions initiated at a one-day symposium entitled The Adolescent Brain: A second window of opportunity, held on 4 May 2016 at UNICEF headquarters in New York. The event brought together specialists to review the state of science related to the adolescent brain, specifically focusing on how to guide future responses to programming and policy and providing directions for research to further advance these aims. The advances and investments made in ECD must be continued for children in their second decade of life. Adolescence is a time of both opportunity and vulnerability. Many problematic and risky behaviours are activated in adolescence, including substance abuse, and behaviours that can lead to sexually transmitted diseases HIV/AIDS, road injuries, drowning and other negative outcomes (Mokdad, 2016). It is a time when mental illness and the incidence of suicide sharply increases (Petroni, Patel and Patton, 2016) and when experiences of bullying, inter-personal violence and exclusion often leave a long-term mark on the individual (Lupien, 2012). The commentaries in this compendium together summarize the state of adolescent neuroscience, reflecting on what is known about positive and negative impacts on brain development, including the effects of poverty, violence, stress, technology, but also socio-emotional learning, meditation, nutrition, counselling and positive relationships. They go beyond the science to discuss its application for maximizing the potential of adolescents. This compendium is designed to encourage further dialogue stimulated by new thinking grounded in adolescent neuroscience research and its application. It aims to challenge readers to bring science to bear on programme interventions and public policies for adolescents. An improved understanding from neuroscience is well-placed to strengthen behavioural evidence and provide a more complete picture of adolescent behaviour and development, while also stimulating fresh thinking and approaches that can be tested

A transdisciplinary perspective of chronic stress in relation to psychopathology throughout life span development

The allostatic load (AL) model represents an interdisciplinary approach to comprehensively conceptualize and quantify chronic stress in relation to pathologies throughout the life cycle. This article first reviews the AL model, followed by interactions among early adversity, genetics, environmental toxins, as well as distinctions among sex, gender, and sex hormones as integral antecedents of AL. We next explore perspectives on severe mental illness, dementia, and caregiving as unique human models of AL that merit future investigations in the field of developmental psychopathology. A complimenting transdisciplinary perspective is applied throughout, whereby we argue that the AL model goes beyond traditional stress–disease theories toward the advancement of person-centered research and practice that promote not only physical health but also mental healt

Associations between jet lag and cortisol diurnal rhythms after domestic travel.

Objective: Millions of adults in the United States travel abruptly across time zones each year. Nevertheless, the impact of traveling over relatively short distances (across 3 or fewer time zones) on diurnal patterning of typical physiological response patterns has yet to be studied in a large, epidemiological sample. Design: The current research focuses on 764 middle-aged men comparing variations in diurnal cortisol regulation based on number of time zones traveled eastward or westward the day before. Main Outcome Measure: Participants provided samples of salivary cortisol at waking, 30-min postwaking, 10 a.m., 3 p.m., and bedtime. Results: Eastward travel was associated with a steeper salivary cortiso

Le vieillissement du cerveau et le vieillissement de l’esprit : Une suite naturelle ?

On associe bien souvent le vieillissement du cerveau à une mort lente de l’esprit, menant inexorablement à des troubles de la mémoire et / ou à un déclin général des fonctions cognitives. Cette idée négative du vieillissement du cerveau et de l’esprit puise sa source dans les études scientifiques entreprises au cours des années 1970. Toutefois, vers le milieu des années 1980, un second courant d’études est apparu, qui a clairement démontré que la mort de l’esprit n’est pas du tout une conséquence inexorable du vieillissement humain. Ce courant d’étude s’applique à décrire les déterminants biologiques et psychologiques du vieillissement et à démontrer que la mémoire ne meurt pas. Une telle donnée scientifique a une portée sociale importante, car elle suggère que le support social que l’on offre à nos aînés pourrait leur permettre de garder leur mémoire intacte pour une longue période de temps.We often associate an aging brain to an aging mind, with the underlying idea that aging of the brain will inevitably lead to a significant decline in memory function and/or general cognitive processes. This negative view of aging came from scientific studies performed in the 1970’s. However, in the 1980’s, another theoretical view emerged, which showed that the death of the mind is not an inevitable consequence of human aging. The goal of these studies is to describe the biological and psychological determinants of aging, and to demonstrate that memory never dies. Such a scientific concept has a clear social implication, since it suggests that social support given to our elders could allow them to keep their memory healthy for a very long period of time