Mild daily stress, in interaction with NR3C1 DNA methylation levels, is linked to alterations in the HPA axis and ANS response to acute stress in early adolescents.

BACKGROUND: Daily Hassles (DH) or daily stress - is a mild type of stressor with unique contributions to psychological distress. Yet, most prior studies that investigate the effects of stressful life experiences focus on childhood trauma or on early life stress and little is known about the effects of DH on epigenetic changes in stress system related genes and on the physiological response to social stressors. METHODS: In the present study, conducted among 101 early adolescents (mean age = 11.61; SD = 0.64), we investigated whether Autonomic Nervous System (ANS) (namely heart rate and heart rate variability) and Hypothalamic-Pituitary-Adrenal (HPA) axis functioning (measured as cortisol stress reactivity and recovery) are associated with DNA methylation (DNAm) in the glucocorticoid receptor gene (NR3C1), the level of DH and their interaction. To assess the stress system functioning the TSST protocol was used. RESULTS: Our findings show that higher NR3C1 DNAm in interaction with higher levels of daily hassles, is associated with blunted HPA axis reactivity to psychosocial stress. In addition, higher levels of DH are associated with extended HPA axis stress recovery. In addition, participants with higher NR3C1 DNAm had lower ANS adaptability to stress, specifically lower parasympathetic withdrawal; for heart rate variability this effect was strongest for participants with higher level of DH. CONCLUSIONS: The observation that interaction effects between NR3C1 DNAm levels and daily stress on the functioning of the stress-systems, are already detectable in young adolescents, highlights the importance of early interventions, not only in the case of trauma, but also daily stress. This might help to prevent stress-induced mental and physical disorders later in life.

Individual differences in environmental sensitivity at physiological and phenotypic level: Two sides of the same coin?

Young adolescents are hypothesized to differ in their environmental sensitivity, at both phenotypic (i.e., Sensory Processing Sensitivity [SPS]) and physiological (i.e., biological stress response) level. This is the first study that investigated whether individual differences in environmental sensitivity at physiological level could be predicted by individual differences at phenotypic level, as measured with the HSC scale. A total of 101 adolescents (Mage = 11.61, SDage = 0.64) participated in a standardized social stress task (i.e., Trier Social Stress Task-Modified version for children and adolescents (TSST-M)). From baseline to the end of recovery, eight cortisol samples were collected, as well as a continuous measure of Autonomic Nervous System activity. Adolescents reported on SPS and on perceived stress before, during, and after TSST-M. As a follow-up analysis, the quality of the environment, the possible overlap with Neuroticism, and several covariates were considered. Multilevel models were used to investigate within- and between-person differences in stress reactivity across different systems. Results indicate significant individual differences in heart rate, heart rate variability, skin conductance, cortisol, and perceived stress in response to the TSST-M. Only for perceived stress significant differences in SPS were observed, with more sensitive individuals perceiving more negative and less positive affect. For environmental quality and the interaction between SPS and Neuroticism results showed higher recovery rates of heart rate in high quality environments and stronger cortisol responses for adolescents scoring high on both SPS and Neuroticism. Potential explanations for these findings and implications for current theorizing on environmental sensitivity are discussed.

Improving the Measurement of Environmental Sensitivity in Children and Adolescents: The Highly Sensitive Child Scale-21 Item Version.

Children differ in their sensitivity to positive and negative environmental influences, which can be measured with the Highly Sensitive Child (HSC) scale. The present study introduces the HSC-21, an adaptation of the original 12 item scale with new items and factor structure that are meant to be more informative than the original ones. The psychometric properties of the HSC-21 were investigated in 1,088 children across Belgium and the Netherlands, including child and mother reports. Results showed evidence for (a) bifactor model with a general sensitivity factor and two specific factors (i.e., Ease of Excitation-Low Sensory Threshold and Aesthetic Sensitivity); (b) (partial) measurement invariance across gender, developmental stage, country, and informants; (c) moderate child-mother agreement; (d) good reliability; (e) normally distributed item scores; and (f) meaningful associations with personality and temperament across both samples. No evidence was found for HSC-21 as a moderator in the relationship between parenting and problem behaviors.