ABSTRACT
There is growing evidence for dysregulation of the stress system in individuals with Attention Deficit Hyperactivity Disorder (ADHD). The stress system includes neuroanatomical and functional components that function in concert to maintain homeostasis and its main effectors are the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic/adrenomedullary nervous system (SNS). As stress system activity demonstrates a distinct circadian variation, we aimed to describe simultaneously, diurnal rhythms of both the HPA axis and the SNS in children with ADHD and a comparison group. Moreover, we attempted to investigate stress responses to a physical stressor, venipuncture, in both groups. Sixty-two prepubertal children with ADHD combined (ADHD-C) or inattentive (ADHD-I) type and 40 typically developing children provided saliva samples at six specific time points during a day, as well as before and 10â¯min after a scheduled morning venipuncture. Salivary cortisol and α- amylase were selected as reliable noninvasive biomarkers for HPA axis and SNS function and were measured in the samples obtained. Results revealed that children with ADHD-C had lower mean cortisol values both 30â¯min after awakening and at 18:00â¯h than controls (pâ¯=â¯0.002 and pâ¯=â¯0.018 respectively), as well as lower mean Cortisol Awakening Response (CAR) and Area Under the Curve for "wake to bed" period (AUCi) values of cortisol (pâ¯=â¯0.004 and pâ¯=â¯0.001, respectively). Also, mean CAR and cortisol AUCi were lower in children with ADHD-I than the control group (pâ¯=â¯0.034 and pâ¯=â¯0.038 respectively). Alpha-amylase measurements showed an increase over time (pâ¯<â¯0.001), which was similar in all three groups. Interestingly, α-amylase changes over time were correlated with the corresponding cortisol changes (pâ¯<â¯0.001). Venipuncture, elicited a significant increase only in α-amylase levels and more so in the control group (pâ¯=â¯0.003). These findings suggest a partial hypofunction of the stress system in children with ADHD.
Subject(s)
Attention Deficit Disorder with Hyperactivity/metabolism , Hydrocortisone/metabolism , Saliva/metabolism , Stress, Psychological/metabolism , alpha-Amylases/metabolism , Attention Deficit Disorder with Hyperactivity/enzymology , Attention Deficit Disorder with Hyperactivity/genetics , Biomarkers/metabolism , Child , Circadian Rhythm/physiology , Female , Humans , Hypothalamo-Hypophyseal System/metabolism , Male , Pituitary-Adrenal System/metabolism , Stress, Psychological/enzymologyABSTRACT
BACKGROUND: Brain-derived neurotrophic factor (BDNF) is a neurotrophin that has a protective role in the nervous system and is involved in neural plasticity. It is abundant in the central nervous system, but is also expressed in the gastrointestinal tract. Coeliac disease (CD), characterised by intestinal inflammation, has some comorbidity with neurologic and mental disorders. The aim of this study was to evaluate circulating BDNF concentrations in patients with CD at diagnosis or on a gluten-free diet (GFD) for longer than 1 year and in healthy controls (HC). MATERIALS AND METHODS: Fifty newly diagnosed patients with CD (aged 8.6 ± 3.7 years, 64.0% females), thirty-nine patients on GFD for longer than 1 year (aged 10.4 ± 3.4 years, 71.8% females) and 36 HC (aged 8 ± 1.7 years, 33.3% females) were included in the study. Along with anthropometric evaluation and standard blood chemistry, serum BDNF levels were measured by a specific immunoenzymatic assay. RESULTS: Patients at diagnosis and on GFD had significantly higher BDNF levels (26 110 ± 8204 and 28 860 ± 7992 pg/mL), respectively, than HC (19 630 ± 8093 pg/mL, P < .001 for both CD groups). Patients on GFD had significantly higher BDNF levels than those at diagnosis (P = .02). CONCLUSIONS: Serum BDNF concentrations were higher in patients with CD than in HC, regardless of their status of gluten consumption. This could be attributed either to a potential protective response to the inflammation of the intestine or to chronic stress.
Subject(s)
Brain-Derived Neurotrophic Factor/metabolism , Celiac Disease/blood , Age of Onset , Case-Control Studies , Celiac Disease/diet therapy , Child , Diet, Gluten-Free , Female , Humans , Immunoenzyme Techniques , Male , Medication AdherenceABSTRACT
The aim of this study was to explore the relation between mothers' parenting stress and the functioning of the hypothalamic-pituitary-adrenal axis (HPAA), as expressed by daily salivary cortisol concentrations, in their children diagnosed with attention deficit hyperactivity disorder (ADHD). Seventy-five children aged 6-11 years diagnosed with ADHD predominant hyperactive-impulsive/combined (ADHD-HI/C, N = 49) and inattentive symptoms (ADHD-I, N = 26) and 45 healthy peers and their mothers participated in the study. Μothers completed measures assessing their children's ADHD status, perceived parenting stress (Parenting Stress Index - Short Form, PSI-SF), mothers' symptoms of psychopathology, social support and socioeconomic status. Children's salivary cortisol samples were collected at six different time points on a single day. Mothers of children with ADHD-HI/C reported higher levels of parenting stress than mothers of children with ADHD-I and controls. All PSI-SF subscales showed significant associations with children's cortisol awakening response (CAR) in both ADHD groups, with the exception of the parental distress subscale in the ADHD-I group. In both ADHD groups, the parent-child dysfunctional interaction subscale, the difficult child subscale and the PSI total score were significantly associated with children's CAR. An interrelation is revealed between mothers' high levels of parenting stress and HPAA functioning in children with ADHD. In this population, CAR has been identified as a sensitive peripheral measure of HPAA functioning in children. Lay summaryThis study showed that in families of children diagnosed with ADHD, there is a complex relation between the mothers' high levels of parenting stress and children's atypical hypothalamic-pituitary-adrenal axis functioning.
