The specialist predator protects termite colonies from generalist predators

Contains fulltext : 143439.pdf (publisher's version ) (Open Access)BACKGROUND: Children of parents with a substance use disorder (CPSUD) are at increased risk for developing problematic substance use later in life. Endophenotypes may help to clarify the mechanism behind this increased risk. However, substance use and externalizing symptoms may confound the relation between dysregulated physiological stress responding and familial risk for substance use disorders (SUDs). METHODS: We examined whether heart rate (HR) responses differed between CPSUDs and controls. Participants (aged 11-20years) were CPSUDs (N=75) and controls (N=363), semi-matched on the basis of sex, socioeconomic status, and ethnicity. HR was measured continuously during a psychosocial stress procedure. Substance use and externalizing symptoms were self-reported and mother-reported, respectively. RESULTS: A piecewise, mixed-effects model was fit for HR across the stress procedure, with fixed effects for HR reactivity and HR recovery. CPSUDs showed a blunted HR recovery. CPSUDs reported drinking more frequently, were more likely to use tobacco daily, were more likely to report ever use of cannabis and used cannabis more frequently, and exhibited more externalizing symptoms. These variables did not confound the relation between familial risk for SUDs and a blunted HR recovery. CONCLUSION: Our findings suggest dysregulated autonomic nervous system (ANS) responding in CPSUDs and contribute to the accumulating evidence for ANS dysregulation as a potential endophenotype for SUDs.9 p

Oxytocin moderates the association between testosterone-cortisol ratio and trustworthiness:A randomized placebo-controlled study

Oxytocin has been proposed to enhance feelings of trust, however, these findings have been difficult to replicate. Environmental or hormonal factors might influence this association. We studied whether oxytocin moderates the association between the testosterone-cortisol ratio, which is associated with risk taking behavior and aggression, and trustworthiness, while controlling for the general level of trust. A randomized double-blind placebo-controlled study with 53 healthy males was performed in which 32IU oxytocin (n = 27) or placebo (n = 26) was administered intranasally. Participants subsequently played the Trust Game in which they were allocated to the role of trustee. In the third phase of the Trust Game, we found a positive association between the testosterone-cortisol-ratio and the proportion of the amount that is returned to the investor (P=<0.01). However, administration of oxytocin reduced reciprocity in those with a high testosterone-cortisol ratio after reciprocity restoration (a significant interaction effect between administration of oxytocin and the testosterone-cortisol ratio in the third phase of the Trust Game, P = 0.015). The third phase of the Trust Game represents the restoration of reciprocity and trustworthiness, after this is violated in the second phase. Therefore, our data suggest that oxytocin might hinder the restoration of trustworthiness and diminish risk-taking behavior when trust is violated, especially in those who are hormonally prone to risk-taking behavior by a high testosterone-cortisol ratio

Diurnal cortisol patterns of young male patients with schizophrenia

Aims: it has been suggested that schizophrenic patients are more vulnerable to stress than healthy persons, and that stressors can trigger a psychotic episode or worsen symptoms. The biological system often studied in relation to stress is the hypothalamic–pituitary–adrenal (HPA) axis, which controls the release of cortisol. We investigated whether the diurnal basal activity of the HPA axis differed between young male patients with schizophrenia and healthy controls.Methods: twenty-seven male patients (mean age 22 ± 5 years) and 38 healthy male control subjects (mean age 22 ± 3 years) were included in the present study. Saliva was sampled at five time points during the day: directly after awakening, 30 min thereafter, and at 12.00 hours, 16.00 hours and 22.00 hours.Results: the cortisol concentration decreased significantly more during the day in the patient group thanin the control group. Patients also showed a significantly decreased area under the curve with respect to the increase, again indicating that the cortisol concentrations decreased more during the day in patients than in controls. Both the morning increase and the area under the curve with respect to the increase were significantly negatively correlated with negative symptom severity.Conclusions: patients with schizophrenia showed a different daytime sensitivity of the HPA axis. Our findings further suggest that an increase in negative symptom severity is related to a decreased HPA axis sensitivit

Low autonomic arousal as vulnerability to externalising behaviour in infants with hostile mothers

Maternal psychopathology and the child's autonomic nervous system functioning are risk factors for aggressive behaviour later in life. While research has shown that maternal psychopathology already affects young children, less is known about the association between autonomic functioning and aggressive behaviour in young children. In addition, maternal psychopathology and autonomic nervous system functioning may interact to determine the risk of aggressive behaviour.In a sample of 375 infants and their mothers, maternal psychiatric symptoms were assessed with the Brief Symptom Inventory and toddler aggressive behaviour with the Child Behaviour Checklist. Infant heart rate was recorded at 14. months.Maternal psychiatric problems, including hostility and depression, were associated with toddler aggressive behaviour. Maternal psychiatric problems interacted with mean heart rate (P= 0.01) and HF variability (P= 0.03) in their effect on toddler aggressive behaviour.Mothers with high psychiatric problems, in particular, high hostility, were more likely to have toddlers with high aggressive behaviour. Moreover, in the presence of maternal risk factors, low autonomic arousal renders children particularly susceptible to aggressive behaviour

CBT for childhood anxiety disorders: differential changes in selective attention between treatment responders and non-responders

Background:This study examined whether treatment response to stepped-care cognitive-behavioural treatment (CBT) is associated with changes in threat-related selective attention and its specific components in a large clinical sample of anxiety-disordered children.Methods:Ninety-one children with an anxiety disorder were included in the present study. Children received a standardized stepped-care CBT. Three treatment response groups were distinguished: initial responders (anxiety disorder free after phase one: child-focused CBT), secondary responders (anxiety disorder free after phase two: child-parent-focused CBT), and treatment non-responders. Treatment response was determined using a semi-structured clinical interview. Children performed a pictorial dot-probe task before and after stepped-care CBT (i.e., before phase one and after phase two CBT).Results:Changes in selective attention to severely threatening pictures, but not to mildly threatening pictures, were significantly associated with treatment success. At pre-treatment assessment, initial responders selectively attended away from severely threatening pictures, whereas secondary responders selectively attended toward severely threatening pictures. After stepped-care CBT, initial and secondary responders did not show any selectivity in the attentional processing of severely threatening pictures. Treatment non-responders did not show any changes in selective attention due to CBT.Conclusions:Initial and secondary treatment responders showed a reduction of their predisposition to selectively attend away or toward severely threatening pictures, respectively. Treatment non-responders did not show any changes in selective attention. The pictorial dot-probe task can be considered a potentially valuable tool in assigning children to appropriate treatment formats as well as for monitoring changes in selective attention during the course of CBT

A Study of the anoplocephaline cestodes of North American rabbits

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Descriptives of stress reactivity variables.

<p><i>Notes.</i> RSA = respiratory sinus arrhythmia; PPS = perceived physiological stress.</p

Results of the multiple linear regression models, predicting each stress response in the child sample.

<p><i>Notes.</i> SES = socioeconomic status; RSA = respiratory sinus arrhythmia; PPS = perceived physiological stress; adjusted R² reported; sample sizes for each reactivity model: cortisol (<i>n</i> = 336), heart rate (<i>n</i> = 320); RSA (<i>n</i> = 184); PPS (<i>n</i> = 251); F statistics pertain to model results, β statistics refer to standardized coefficients of individual predictors.</p

Raw data for each of the stress response variables across the psychosocial stress procedure in children and adolescents.

<p><i>Notes.</i> MAT = mental arithmetic task; PST = public speaking task; CT = computer task; bpm = beats per minute.</p

Descriptive statistics of all potential determinants of stress reactivity.

<p><i>Notes.</i> F = frequency in percentage; Cα = Cronbach's alpha; m = mother; f = father; SES = socioeconomic status.</p