Stress-related genetic components in attention-deficit/hyperactivity disorder (ADHD): Effects of the SERPINA6 and SERPINA1 genetic markers in a family-based brazilian sample

Hair cortisol concentration and mental health during childhood and adolescence: evidence that higher cortisol concentration is associated with externalizing problems in a large Brazilian population-based birth cohort

Childhood and adolescence are pivotal periods for mental health. The hypothalamic-pituitary-adrenal axis is the primary stress system and its chronic activation is measurable via hair cortisol concentration (HCC), indicating long-term stress exposure. While HCC is linked to adult mental health, this relationship remains unclear among youth. Although a bidirectional relationship is possible, the impact of mental health problems on HCC in youths has been comparatively underexplored. This study aimed to assess the association between symptoms of mental health problems in childhood and adolescence and HCC levels at age 15 in a Brazilian population-based cohort. We analyzed data from the 2004 Pelotas Birth Cohort, which includes 4,231 children followed from birth. At ages 6, 11 and 15 years, mental health symptoms were assessed using the Strengths and Difficulties Questionnaire (SDQ). At age 15, HCC was measured from 3 cm hair samples, quantified through the enzyme-linked immunosorbent assay. To evaluate the cumulative impact of mental health symptoms from childhood to adolescence, group-based trajectory analysis was conducted. Subsequently, linear regression models were used to estimate associations between mental health scores and HCC, with adjustment for relevant covariates. Regression coefficients were exponentiated to improve interpretability. SDQ total difficulties (β = 1.004 [1.000;1.008]) and conduct problems (β = 1.017 [1.004;1.030]) at age 6 were associated with HCC at age 15 in adjusted models. Hyperactivity/inattention symptoms at ages 6 (β = 1.009 [1.001;1.018]) and 11 (β = 1.013 [1.004;1.022]) were associated with HCC in adjusted models. At age 15, hyperactivity/inattention symptoms and HCC was associated with HCC in the partially adjusted model (β = 1.009 [1.000;1.017]). Trajectories of chronic conduct problems and hyperactivity between ages 6 and 15 were also associated with elevated HCC, although for hyperactivity/inattention symptoms the association was not significant. These associations emphasize the links between mental health and chronic stress over time, especially between both conduct problems and hyperactivity/inattention symptoms in relation to higher concentrations of HCC.

Moderating effects of impulsivity and morning cortisol on the genotype-phenotype relationship of attention deficit hyperactivity disorder in young adults

Dysregulation of the morning cortisol response in young adults with attention deficit hyperactivity disorder (ADHD) has been shown to underlie several of the alterations present in their lives. Thus, the interaction of this mechanism with genetic and behavioural characteristics could explain a large proportion of the aetiology of ADHD in this population. For these reasons, the present study explores the associations of 30 single nucleotide polymorphisms (SNPs) previously identified as significant (after correction for multiple comparisons) in the aetiology of ADHD with an assessment of morning cortisol and impulsivity traits in a group of 120 adults aged 18-24 years. Participants were recruited through private centres of neuropsychology and psychiatry, as well as through events in local universities. Morning cortisol within 30 min of awakening and motor impulsivity traits were shown to moderate the effect of SNP rs10129500 on the severity of the symptoms of ADHD measured by the Adult Self-Report Scale. This variant associated with cortisol-binding globulin would explain the low concentrations of this hormone found in young adults with high symptoms of ADHD, which is accentuated when there are high levels of impulsivity. The proposed model allows for transferring the theoretical relationships between the dimensions that explain the aetiology of ADHD to an applied exploratory model with good performance.

A bidirectional Mendelian randomization study about the role of morning plasma cortisol in attention deficit hyperactivity disorder

Context

Cortisol, a hormone regulated by the hypothalamic-pituitary-adrenal (HPA) axis, has been linked to attention deficit hyperactivity disorder (ADHD). The nature of the relationship between cortisol and ADHD, and whether it is causal or explained by reverse causality, remains a matter of debate.

Objective

This study aims to evaluate the bidirectional causal relationship between morning plasma cortisol levels and ADHD.

Methods

This study used a bidirectional 2-sample Mendelian randomization (MR) design to analyze the association between morning plasma cortisol levels and ADHD using genetic information from the authoritative Psychiatric Genomics Collaboration (PGC) database (n = 55,347) and the ADHD Working Group of the CORtisol NETwork (CORNET) Consortium (n = 12,597). MR analyses were employed: inverse variance weighting (IVW), MR-Egger regression, and weighted medians. OR values and 95% CI were used to evaluate whether there was a causal association between morning plasma cortisol levels on ADHD and ADHD on morning plasma cortisol levels. The Egger-intercept method was employed to test for level pleiotropy. Sensitivity analysis was performed using the "leave-one-out" method, MR pleiotropy residual sum, and MR pleiotropy residual sum and outlier (MR-PRESSO).

Results

Findings from bidirectional MR demonstrated that lower morning plasma cortisol levels were associated with ADHD (ADHD-cortisol OR = 0.857; 95% CI, 0.755-0.974; P = 0.018), suggesting there is a reverse causal relationship between cortisol and ADHD. However, morning plasma cortisol levels were not found to have a causal effect on the risk of ADHD (OR = 1.006; 95% CI, 0.909-1.113; P = 0.907), despite the lack of genetic evidence. The MR-Egger method revealed intercepts close to zero, indicating that the selected instrumental variables had no horizontal multiplicity. The "leave-one-out" sensitivity analysis revealed stable results, with no instrumental variables significantly affecting the results. Heterogeneity tests were insignificant, and MR-PRESSO did not detect any significant outliers. The selected single-nucleotide polymorphisms (SNPs) F were all >10, indicating no weak instrumental variables. Thus, the overall MR analysis results were reliable.

Conclusion

The study findings suggest a reverse causal relationship between morning plasma cortisol levels and ADHD, with low cortisol levels associated with ADHD. No genetic evidence was found to support a causal relationship between morning plasma cortisol levels and the risk of ADHD. These results suggest that ADHD may lead to a significant reduction in morning plasma cortisol secretion.

Corticosteroid-binding globulin (CBG): spatiotemporal distribution of cortisol in sepsis

Corticosteroid-binding globulin (CBG) is a 50-60 kDa circulating glycoprotein with high affinity for cortisol. CBG is adapted for sepsis; its cortisol binding is reduced reversibly by pyrexia and acidaemia, and reduced irreversibly by neutrophil elastase (NE) cleavage, converting high cortisol-binding affinity CBG to a low affinity form. These characteristics allow for the targeted delivery of immunomodulatory cortisol to tissues at the time and body site where cortisol is required in sepsis and septic shock. In addition, high titer inflammatory cytokines in sepsis suppress CBG hepatic synthesis, increasing the serum free cortisol fraction. Recent clinical studies have highlighted the importance of CBG in septic shock, with CBG deficiency independently associated with mortality.