970 resultados para stress reactivity
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OBJECTIVE: To investigate the relationship between social support and coagulation parameter reactivity to mental stress in men and to determine if norepinephrine is involved. Lower social support is associated with higher basal coagulation activity and greater norepinephrine stress reactivity, which in turn, is linked with hypercoagulability. However, it is not known if low social support interacts with stress to further increase coagulation reactivity or if norepinephrine affects this association. These findings may be important for determining if low social support influences thrombosis and possible acute coronary events in response to acute stress. We investigated the relationship between social support and coagulation parameter reactivity to mental stress in men and determined if norepinephrine is involved. METHODS: We measured perceived social support in 63 medication-free nonsmoking men (age (mean +/- standard error of the mean) = 36.7 +/- 1.7 years) who underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience. We measured plasma D-dimer, fibrinogen, clotting Factor VII activity (FVII:C), and plasma norepinephrine at rest as well as immediately after stress and 20 minutes after stress. RESULTS: Independent of body mass index, mean arterial pressure, and age, lower social support was associated with higher D-dimer and fibrinogen levels at baseline (p < .012) and with greater increases in fibrinogen (beta = -0.36, p = .001; DeltaR(2) = .12), and D-dimer (beta = -0.21, p = .017; DeltaR(2) = .04), but not in FVII:C (p = .83) from baseline to 20 minutes after stress. General linear models revealed significant main effects of social support and stress on fibrinogen, D-dimer, and norepinephrine (p < .035). Controlling for norepinephrine did not change the significance of the reported associations between social support and the coagulation measures D-dimer and fibrinogen. CONCLUSIONS: Our results suggest that lower social support is associated with greater coagulation activity before and after acute stress, which was unrelated to norepinephrine reactivity.
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Hypertension is a known risk factor for cardiovascular disease. Hypertensive individuals show exaggerated norepinephrine (NE) reactivity to stress. Norepinephrine is a known lipolytic factor. It is unclear if, in hypertensive individuals, stress-induced increases in NE are linked with the elevations in stress-induced circulating lipid levels. Such a mechanism could have implications for atherosclerotic plaque formation. In a cross-sectional, quasi-experimentally controlled study, 22 hypertensive and 23 normotensive men (mean +/- SEM, 45 +/- 3 years) underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience. We measured plasma NE and the plasma lipid profile (total cholesterol [TC], low-density-lipoprotein cholesterol [LDL-C], high-density-lipoprotein cholesterol, and triglycerides) immediately before and after stress and at 20 and 60 minutes of recovery. All lipid levels were corrected for stress hemoconcentration. Compared with normotensives, hypertensives had greater TC (P = .030) and LDL-C (P = .037) stress responses. Independent of each other, mean arterial pressure (MAP) upon screening and immediate increase in NE predicted immediate stress change in TC (MAP: beta = .41, P = .003; NE: beta = .35, P = .010) and LDL-C (MAP: beta = .32, P = .024; NE: beta = .38, P = .008). Mean arterial pressure alone predicted triglycerides stress change (beta = .32, P = .043) independent of NE stress change, age, and BMI. The MAP-by-NE interaction independently predicted immediate stress change of high-density-lipoprotein cholesterol (beta = -.58, P < .001) and of LDL-C (beta = -.25, P < .08). We conclude that MAP and NE stress reactivity may elicit proatherogenic changes of plasma lipids in response to acute psychosocial stress, providing one mechanism by which stress might increase cardiovascular risk in hypertension.
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BACKGROUND: The incidence and prevalence of cardiovascular disease (CVD) increases with age. Some evidence suggests that mental stress may increase plasma homocysteine (Hcy), an amino acid relating to CVD. However, none of these studies assessed age effects on Hcy stress reactivity, nor did they control for age. The objective of this study was (a) to investigate whether Hcy reactivity to psychosocial stress differs between younger and middle-aged to older men and (b) to study whether psychosocial stress induces Hcy increases independent of age. METHODS: Twenty eight younger (20-30 years) and 22 middle-aged to older (47-65 years) apparently healthy men underwent an acute standardized psychosocial stress task combining public speaking and mental arithmetic in front of an audience. Blood samples for Hcy measurements were obtained immediately before and after, as well as 10 and 20min after stress. Moreover, salivary cortisol was repeatedly measured to test the effectiveness of the stress task in triggering a neuroendocrine stress response. RESULTS: Hcy reactivity to stress differed between age groups (F(1.4, 60.7)=5.41, p=.014). While the older group displayed an increase in the Hcy response to stress (F(2.5, 39.8)=3.86, p=.022), Hcy levels in the younger group did not change (p=.27). Psychosocial stress per se did not change Hcy levels independent of age (p=.53). CONCLUSIONS: Our findings suggest that psychosocial stress does not evoke an Hcy response per se, but only in interaction with age pointing to a mechanism by which mental stress may increase CVD risk in older individuals.
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BACKGROUND: We investigated the psychometric properties of a short questionnaire for combined assessment of different perceived stress management skills in the general population and tested whether scores relate to physiological stress reactivity. METHODS: For psychometric evaluation, we determined the factor structure of the questionnaire and investigated its measurement invariance in the participant groups and over time in three different independent samples representing the general population (total N=332). Reliability was tested by estimating test-retest reliability, internal consistency, and item reliabilities. We examined convergent and criterion validity using selected criterion variables. For endocrine validation, 35 healthy non-smoking and medication-free men in a laboratory study and 35 male and female employees in a workplace study underwent an acute standardized psychosocial stress task. We assessed stress management skills and measured salivary cortisol before and several times up to 60 min (workplace study) and 120 min (laboratory study) after stress. Potential confounders were controlled. RESULTS: The factor structure of the questionnaire consists of five scales reflecting acceptably distinct stress management skills such as cognitive strategies, use of social support, relaxation strategies, anger regulation, and perception of bodily tension. This factor structure was stable across participant groups and over time. Internal consistencies, item reliabilities, and test-retest reliabilities met established statistical requirements. Convergent and criterion validity were also established. In both endocrine validation studies, higher stress management skills were independently associated with lower cortisol stress reactivity (p's<.029). CONCLUSIONS: Our findings suggest that the questionnaire has good psychometric properties and that it relates to subjective psychological and objective physiological stress indicators. Therefore, the instrument seems a suitable measure for differential assessment of stress management skills in the general population.
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Theoretical background and objectives: Stress reducing effects of Taiji practice have been repeatedly reported. The aim of the present study was to investigate which persons benefit the most from Taiji practice in terms of reduced physiological stress reactivity. Methods: We conducted a secondary data analysis of a randomized controlled Taiji trial that significantly lowered stress reactivity of salivary cortisol and alpha-amylase in a Taiji group (n = 26) compared to a control group (n = 23). By using hierarchical regression analyses potential moderating influences of self-reported trait-mindfulness and trait values of general psychological stress reactivity on stress protective effects of a three months Taiji training were examined. Moderator variables were assessed at the beginning of the study using the Freiburg-Mindfulness-Inventory and the Perceived- Stress-Reactivity-Scale. Results: The interaction effect "study group x mindfulness" was significant for stress reactivity of salivary alpha-amylase (p = 0.050). Participants in the Taiji group with higher trait-mindfulness showed a lower salivary alpha-amylase stress reactivity, while in the control group higher trait-mindfulness was associated with higher alpha-amylase stress reactivity. In the control group (p = 0.042) but not in the Taiji group (p = 0.69) salivary cortisol stress reactivity was significantly increased in persons with higher trait-mindfulness scores. We could not find moderating effects of general psychological stress reactivity. Conclusion: Our results suggest that without intervention higher trait-mindfulness is associated with increased physiological stress reactivity. Persons with higher trait-mindfulness seem to benefit the most from practicing Taiji in terms of reduced sympathetic stress reactivity.
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Flavanoid-rich dark chocolate consumption benefits cardiovascular health, but underlying mechanisms are elusive. We investigated the acute effect of dark chocolate on the reactivity of prothrombotic measures to psychosocial stress. Healthy men aged 20-50 years (mean ± SD: 35.7 ± 8.8) were assigned to a single serving of either 50 g of flavonoid-rich dark chocolate (n=31) or 50 g of optically identical flavonoid-free placebo chocolate (n=34). Two hours after chocolate consumption, both groups underwent an acute standardised psychosocial stress task combining public speaking and mental arithmetic. We determined plasma levels of four stress-responsive prothrombotic measures (i. e., fibrinogen, clotting factor VIII activity, von Willebrand Factor antigen, fibrin D-dimer) prior to chocolate consumption, immediately before and after stress, and at 10 minutes and 20 minutes after stress cessation. We also measured the flavonoid epicatechin, and the catecholamines epinephrine and norepinephrine in plasma. The dark chocolate group showed a significantly attenuated stress reactivity of the hypercoagulability marker D-dimer (F=3.87, p=0.017) relative to the placebo chocolate group. Moreover, the blunted D-dimer stress reactivity related to higher plasma levels of the flavonoid epicatechin assessed before stress (F=3.32, p = 0.031) but not to stress-induced changes in catecholamines (p's=0.35). There were no significant group differences in the other coagulation measures (p's≥0.87). Adjustments for covariates did not alter these findings. In conclusion, our findings indicate that a single consumption of flavonoid-rich dark chocolate blunted the acute prothrombotic response to psychosocial stress, thereby perhaps mitigating the risk of acute coronary syndromes triggered by emotional stress.
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La sérotonine (5-HT) joue un rôle crucial dans l'étiologie des troubles mentaux comme la dépression majeure, les troubles de comportement et les troubles anxieux. Des études ont montré que des altérations précoces du système 5-HT peuvent potentiellement influencer le développement du cerveau et le fonctionnement du système fronto-limbique, engendrant des conséquences pour la régulation émotionnelle. Il existe aussi des évidences que le stress précoce peut affecter la méthylation de l'ADN résultant d'une altération de l'expression génique. Toutefois, le lien entre la méthylation de l'ADN et la réactivité comportementale à des facteurs de stress de la vie quotidienne est inconnu. La méthylation du gène transporteur 5-HT (SLC6A4) est d'un intérêt particulier, étant donné le rôle de SLC6A4 dans le développement du cerveau, les troubles mentaux et la régulation du stress. L'objectif de cette thèse est d'étudier l'association entre (1) les niveaux périphériques de méthylation de l'ADN dans le gène SLC6A4 et les réponses neurales aux stimuli émotionnels dans les circuits fronto-limbiques du cerveau, ainsi qu’entre (2) la méthylation périphérique de SLC6A4 et la réactivité comportementale au stress de la vie quotidienne. Nous explorons également l'association entre les réponses neuronales fronto-limbique à des stimuli émotionnels et la réactivité comportementale au stress de la vie quotidienne (3). À cette fin, vingt-deux personnes (11 femmes) d’âge moyen de 34,0 ans (SD : 1,5) avec différents niveaux de méthylation au gène SLC6A4 ont été recrutés à partir de deux études longitudinales. Les participants ont subi une analyse IRMf qui comprenait une tâche de traitement émotionnel. Un questionnaire en ligne sur la réactivité au stress quotidien de la vie a été réalisé pendant 5 jours consécutifs. Des analyses corrélationnelles et de régression ont été effectuées pour examiner les associations entre les variables primaires. Les résultats préliminaires de cette étude ont montré que la méthylation de l'ADN est associée à la désactivation significative du gyrus précentral et gyrus fusiforme respectivement face à des stimuli de peur et de tristesse. Aucune association significative n'a été observée entre les niveaux de méthylation et l'activation de l'amygdale. En outre, les scores obtenus aux variables de stress de la vie quotidienne tels que la détresse chronique ont été associées à la désactivation du précuneus et du cortex cingulaire postérieur face à la tristesse. Ces résultats suggèrent l'implication potentielle des processus épigénétiques dans l'activation cérébrale spécifique et la sensibilité au stress de la vie courante.
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Abstract Significance: Schizophrenia (SZ) and bipolar disorder (BD) are classified as two distinct diseases. However, accumulating evidence shows that both disorders share genetic, pathological, and epidemiological characteristics. Based on genetic and functional findings, redox dysregulation due to an imbalance between pro-oxidants and antioxidant defense mechanisms has been proposed as a risk factor contributing to their pathophysiology. Recent Advances: Altered antioxidant systems and signs of increased oxidative stress are observed in peripheral tissues and brains of SZ and BD patients, including abnormal prefrontal levels of glutathione (GSH), the major cellular redox regulator and antioxidant. Here we review experimental data from rodent models demonstrating that permanent as well as transient GSH deficit results in behavioral, morphological, electrophysiological, and neurochemical alterations analogous to pathologies observed in patients. Mice with GSH deficit display increased stress reactivity, altered social behavior, impaired prepulse inhibition, and exaggerated locomotor responses to psychostimulant injection. These behavioral changes are accompanied by N-methyl-D-aspartate receptor hypofunction, elevated glutamate levels, impairment of parvalbumin GABA interneurons, abnormal neuronal synchronization, altered dopamine neurotransmission, and deficient myelination. Critical Issues: Treatment with the GSH precursor and antioxidant N-acetylcysteine normalizes some of those deficits in mice, but also improves SZ and BD symptoms when given as adjunct to antipsychotic medication. Future Directions: These data demonstrate the usefulness of GSH-deficient rodent models to identify the mechanisms by which a redox imbalance could contribute to the development of SZ and BD pathophysiologies, and to develop novel therapeutic approaches based on antioxidant and redox regulator compounds. Antioxid. Redox Signal. 18, 1428-1443.
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L'étude a pour objectif de mettre en évidence les effets d'une intervention précoce inspirée des thérapies en Guidance Interactive sur la qualité de l'attachement ainsi que sur la réactivité neuroendocrinienne de stress chez des grands prématurés âgés de 12 mois ainsi que chez leurs mères. La population étudiée comprend 48 grands prématurés (<33 semaines de gestation) et leurs mères. Un programme d'intervention précoce a été proposé aléatoirement à la moitié des dyades incluses dans l'étude. Des mesures de cortisol salivaire ont été effectuées à 12 mois lors d'un épisode de stress modéré (la Situation Étrange) tant chez la mère que chez l'enfant. Les mères ayant bénéficié de l'intervention précoce montrent des taux de cortisol plus élevés que celles n'ayant pas bénéficié de l'intervention. Les auteurs font l'hypothèse que ces mères ont pu développer leur sensibilité envers leur enfant et se montrent, par conséquent, plus concernées lors de l'épisode de stress modéré. The present project aims to assess the effects of an early intervention inspired from Interactive Guidance therapy, on later attachment quality and stress reactivity of prematurely born infants and their mothers. The studied population contends 48 preterm born infants (< 33 weeks og gestational age). Half of the dyads receive an intervention program aiming at promoting the parents' responsivity-sensitivity to infant's cues. Infant's and mother's stress reactivity (salivary cortisol) to mild stressors (Strange Situation) will be assessed at 12 months. Mothers with intervention program show higher cortisol levels than the others. The authors postulate that these mothers enhance their caregiving quality and, subsequently, are more prone to be sensitive to infant's cues and to be concerned during the mild stress episode.
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ABSTRACTSchizophrenia is a major psychiatric disorder occurring with a prevalence of 1% in the worldwide population. It develops progressively with psychosis onset in late adolescence or earlyadulthood. The disorder can take many different facets and has a highly diffuse anddistributed neuropathology including deficits in major neurotransmitter systems,myelination, stress regulation, and metabolism. The delayed onset and the heterogeneouspathology suggest that schizophrenia is a developmental disease that arises from interplayof genetic and environmental factors during sensitive periods. Redox dysregulation due to animbalance between pro-oxidants and antioxidant defence mechanisms is among the riskfactors for schizophrenia. Glutathione (GSH) is the major cellular redox regulator andantioxidant. Levels of GSH are decreased in cerebrospinal fluid, prefrontal cortex and postmortemstriatum of schizophrenia patients. Moreover, polymorphisms of the key GSHsynthesizingenzyme, glutamate-cysteine ligase, modifier (GCLM) subunit, are associatedwith the disease, suggesting that GSH deficit is of genetic origin. Here we used miceknockout (KO) for the GCLM gene, which display chronic GSH deficit (~70 to 80% decrease)to investigate the direct link between redox dysregulation and schizophrenia. Accordingly,we evaluated whether GCLM KO compared to normal wildtype mice display behavioralchanges that relate to schizophrenia symptoms and whether their brains showmorphological, functional or metabolic alterations that resemble those in patients.Moreover, we exposed pubertal GCLM mice to repeated mild stress and measured theirhormonal and behavioral stress reactivity. Our data show that chronic GSH deficit isassociated with altered emotion- and stress-related behaviors, deficient prepulse inhibition,pronounced amphetamine-induced hyperlocomotion but normal spatial learning andworking memory. These changes represent important schizophrenia endophenotypes.Moreover, this particular pattern of change indicates impairment of the ventralhippocampus (VH) and related circuitry as opposed to the dorsal hippocampus (DH), which isimplicated in spatial information processing. This is consistent with a selective deficit ofparvalbumin positive interneurons and gamma oscillation in the VH but not DH. Increasedlevels of circulating stress hormones in KO mice following pubertal stress corroborate VHdysfunction as it is involved in negative feedback control of the stress response. VHstructural and functional deficits are frequently found in the schizophrenic brain. Metabolicevaluation of the developing GCLM KO anterior cortex using in vivo magnetic resonancespectroscopy revealed elevated glutamine (Gln), glutamate (Glu), Gln/Glu and N-acetylaspartate(NAA) during the pre-pubertal period. Similar changes are reported in earlyschizophrenia. Overall, we observe phenotypic anomalies in GSH deficient GCLM KO micethat correspond to major schizophrenia endophenotypes. This supports an important rolefor redox dysregulation in schizophrenia and validates the GCLM KO mouse as model for thedisease. Moreover, our results indicate that puberty may be a sensitive period for redoxsensitivechanges highliting the importance of early intervention. Gln, Gln/Glu, Glu and NAAmay qualify as early metabolic biomarkers to identify young at-risk individuals. Since chronictreatment with NAC normalized most metabolic changes in GCLM KO mice, NAC may be oneadjunct treatment of choice for early intervention in patients.RESUMELa schizophrénie est une maladie psychiatrique majeure avec une prévalence de 1% dans lapopulation. Son développement est progressif, les premières psychoses apparaissant àl'adolescence ou au début de l'âge adulte. La maladie a plusieurs présentations et uneneuropathologie étendue, qui inclut des déficits neurochimiques, métaboliques, de lamyélination et de la régulation du stress. L'émergence tardive et l'hétérogénéité de lapathologie suggèrent que la schizophrénie est une maladie développementale, favorisée pardes facteurs génétiques et environnementaux durant des périodes sensibles. La dérégulationrédox, due à un déséquilibre entre facteurs pro-oxidantes et défenses anti-oxidantes,constitue un facteur de risque. Le glutathion (GSH) est le principal régulateur rédox et antioxidantdes cellules, ses taux sont diminués dans le liquide céphalorachidien, le cortexpréfrontal et le striatum de patients. De plus, des variations du gène codant la sous-unitémodulatrice (GCLM) de la glutamate-cystéine ligase, enzyme de synthèse du GSH, sontassociés la maladie, suggérant que le déficit observé chez les patients est d'originegénétique. Nous avons donc utilisé des souris ayant une délétion du gène GCLM (KO), quiont un déficit chronique en GSH (70-80%), afin d'étudier le lien entre une dérégulation rédoxet la schizophrénie. Nous avons évalué si ces souris présentent des altérationscomportementales analogues aux symptômes de la maladie, et des modificationsstructurelles, fonctionnelles et métaboliques au niveau du cerveau, ressemblant à celles despatients. De plus, nous avons soumis les souris à des stresses modérés durant la puberté,puis mesuré les réponses hormonales et comportementales. Les animaux présentent undéficit pré-attentionnel du traitement des informations moto-sensorielles, un déficit pourcertains apprentissages, une réponse accrue à l'amphétamine, mais leurs mémoires spatialeet de travail sont préservées. Ces atteintes comportementales sont analogues à certainsendophénotypes de la schizophrénie. De plus, ces changements comportementaux sontlargement expliqués par une perturbation morphologique et fonctionnelle de l'hippocampeventral (HV). Ainsi, nous avons observé un déficit sélectif des interneurones immunoréactifsà la parvalbumine et une désynchronisation neuronale dans l'HV. L'hippocampe dorsal,impliqué dans l'orientation spatiale, demeure en revanche intact. L'augmentationd'hormones de stress dans le sang des souris KO suite à un stress prépubertal soutien aussil'hypothèse d'une dysfonction de l'HV, connu pour moduler ce type de réponse. Des déficitsstructurels et fonctionnels dans l'hippocampe antérieur (ventral) ont d'ailleurs été rapportéschez des patients schizophrènes. Par de résonance magnétique, nous avons également suivile profil métabolique du le cortex antérieur au cours du développement postnatal des sourisKO. Ces mesures ont révélé des taux élevés de glutamine (Gln), glutamate (Glu), du ratioGln/Glu, et de N-acétyl-aspartate (NAA) durant la période prépubertale. Des altérationssimilaires sont décrites chez les patients durant la phase précoce. Nous avons donc révélédes anomalies phénotypiques chez les souris GCLM KO qui reflètent certainsendophénotypes de la schizophrénie. Nos résultats appuient donc le rôle d'une dérégulationrédox dans l'émergence de la maladie et le potentiel des souris KO comme modèle. De plus,cette étude met en évidence la puberté comme période particulièrement sensible à unedérégulation rédox, renforçant l'importance d'une intervention thérapeutique précoce. Dansce cadre, Gln, Gln/Glu, Glu and NAA seraient des biomarqueurs clés pour identifier de jeunesindividus à risque. De part son efficacité dans notre modèle, NAC pourrait être unesubstance de choix dans le traitement précoce des patients.
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Neonatal handling has long-lasting effects on behavior and stress reactivity. The purpose of the present study was to investigate the effect of neonatal handling on the number of dopaminergic neurons in the hypothalamic nuclei of adult male rats as part of a series of studies that could explain the long-lasting effects of neonatal stimulation. Two groups of Wistar rats were studied: nonhandled (pups were left undisturbed, control) and handled (pups were handled for 1 min once a day during the first 10 days of life). At 75-80 days, the males were anesthetized and the brains were processed for immunohistochemistry. An anti-tyrosine hydroxylase antibody and the avidin-biotin-peroxidase method were used. Tyrosine hydroxylase-immunoreactive (TH-IR) neurons were counted bilaterally in the arcuate, paraventricular and periventricular nuclei of the hypothalamus in 30-µm sections at 120-µm intervals. Neonatal handling did not change the number of TH-IR neurons in the arcuate (1021 ± 206, N = 6; 1020 ± 150, N = 6; nonhandled and handled, respectively), paraventricular (584 ± 85, N = 8; 682 ± 62, N = 9) or periventricular (743 ± 118, N = 7; 990 ± 158, N = 7) nuclei of the hypothalamus. The absence of an effect on the number of dopaminergic cells in the hypothalamus indicates that the reduction in the amount of neurons induced by neonatal handling, as shown by other studies, is not a general phenomenon in the brain.
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Psychological depression is an independent risk factor for coronary artery disease. C-reactive protein has been implicated as a mediator of the effect of psychological depression. Several studies have found that individuals, especially men, who report higher levels of psychological depression also have higher levels of C-reactive protein. The current study was undertaken to replicate these results in a Brazilian population, in which there is a much wider range of variation in both background characteristics (such as socioeconomic status) and coronary artery disease risk factors. A sample of 271 individuals was interviewed using the Center for Epidemiological Studies Depression Scale. Fasting blood samples were obtained and evaluated for C-reactive protein (assessed by a turbidimetric immunoassay using a Dade Behring kit) analysis in a subsample (N = 258) of individuals. The mean ± SD C-reactive protein for the entire sample was 0.43 ± 0.44, with 0.42 ± 0.48 for men and 0.43 ± 0.42 mg/L for women. Data were analyzed using multiple regression analysis, controlling for age, sex, body mass index, socioeconomic status, tobacco use, and both total cholesterol and low-density lipoprotein cholesterol. Higher reported depressive symptoms were correlated with higher C-reactive protein for men (partial r = 0.298, P = 0.004) and with lower C-reactive protein for women (partial r = -0.154, P = 0.059). The differences in the associations for men and women could be a result of differential effects of sex hormones on stress reactivity and immune response. On the other hand, this difference in the associations may be related to gender differences in the disclosure of emotion and the effect that self-disclosure has on physical health and immune response.
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Le trouble du déficit de l’attention/hyperactivité (TDA/H) est un des troubles comportementaux le plus commun chez les enfants. TDAH a une étiologie complexe et des traitements efficaces. Le médicament le plus prescrit est le méthylphénidate, un psychostimulant qui bloque le transporteur de la dopamine et augmente la disponibilité de la dopamine dans la fente synaptique. Des études précliniques et cliniques suggèrent que le cortisol peut potentialiser les effets de la dopamine. Un dysfonctionnement du système hypothalamo-hypophyso-surrénalien (HHS) est associé avec plusieurs maladies psychiatriques comme la dépression, le trouble bipolaire, et l’anxiété. Nous avons fait l’hypothèse que le cortisol influence l’efficacité du traitement des symptômes du TDAH par le méthylphénidate. L’objectif de cette étude est de mesurer les niveaux de cortisol le matin au réveil et en réponse à une prise de sang dans un échantillon d’enfants diagnostiqué avec TDAH âgé de 8 ans. Le groupe était randomisé dans un protocole en chassé croisé et en double aveugle avec trois doses de méthylphénidate et un placebo pour une période de quatre semaines. Les enseignants et les parents ont répondu aux questionnaires SWAN et à une échelle d’évaluation des effets secondaires. Les résultats ont démontrés qu’un niveau de cortisol élevé au réveil prédit les sujets qui ne répondent pas au traitement du TDAH, si on se fie aux rapports des parents. En plus, la réactivité au stress élevé suggère un bénéfice additionnel d’une dose élevée de méthylphénidate selon les enseignants. Aussi, les parents rapportent une association entre la présence de troubles anxieux co-morbide avec le TDAH et une meilleure réponse à une dose élevée. Cette étude suggère qu’une forte réactivité de l’axe HHS améliore la réponse clinique à des doses élevées, mais qu’une élévation chronique du niveau de cortisol pourrait être un marqueur pour les non répondeurs. Les résultats de cette étude doivent être considérés comme préliminaires et nécessitent des tests plus approfondis des interactions possibles entre les médicaments utilisés pour traiter le TDAH et l’axe HHS.
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Background Cognitive Bias Modification (CBM) has been shown to change interpretation biases commonly associated with anxiety and depression and may help ameliorate symptoms of these disorders. However, its evidence base for adolescents is scarce. Previous results have been hard to interpret because of methodological issues. In particular, many studies have used negative bias training as the control condition. This would tend to inflate any apparent benefits of CBM compared to a neutral control. Most studies also only examined the effects of a single training session and lacked follow-up assessment or ecologically valid outcome measures. Method Seventy-four adolescents, aged 16–18 years, were randomised to two sessions of CBM training or neutral control. Interpretation bias and mood were assessed three times: at baseline, immediately post-training and 1 week post-training. A controlled experimental stressor was also used, and responses to everyday stressors were recorded for 1 week after training to assess responses to psychological challenges. Feedback for the training programme was collected. Results The CBM group reported a greater reduction in negative affect than control participants. However, other hypothesised advantages of CBM were not demonstrated. Regardless of training group, participants reported increased positive interpretations, decreased negative interpretations, reduced depressive symptoms and no change in trait anxiety. The two groups did not differ in their stress reactivity. After controlling for group differences in training performance, all the mood effects disappeared. Conclusions When tested under stringent experimental conditions the effects of CBM in healthy adolescents appear to be minimal. Future studies should concentrate on participants with elevated cognitive biases and/or mood symptoms who may be more sensitive to CBM.
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Functional gastrointestinal disorders (FGD) are highly prevalent worldwide. Recent research demonstrates that complex and interacting biological and behavioral mechanisms contribute particularly to the pathogenesis of irritable bowel syndrome and functional dyspepsia. Dysregulation of the enteral, neuroenteric, visceral-autonomic, and central nervous systems are important biological contributors, whereas the psychological state of a patient may evidently modulate aspects related to biological stress reactivity and somatic perception both playing a role in the clinical manifestation of FGD. Our overview clearly shows that an interdisciplinary perspective of the pathogenesis of FGD may best serve clinicians and patients.