The metabolic effects of fasting and surgery

This review discusses the metabolic changes that occur during fasting, especially in relation to surgical stress. Currently available evidence on the relevance of different aspects of perioperative nutritional support are presented. Attenuation of surgical stress and insulin treatment in insulin-resistant patients after surgery and trauma have been shown to markedly affect stress metabolism as well as patient morbidity and mortality. Avoiding preoperative fasting has been shown to be related to a substantial reduction in postoperative stress and insulin resistance. Implementation of a standardized programme with a multimodal approach using evidence-based perioperative routines has been shown to further reduce surgical stress and to markedly enhance functional recovery also after major surgical procedures.

Stress, the hippocampus and the hypothalamic-pituitary-adrenal axis: implications for the development of psychotic disorders

OBJECTIVE

The experience of stress is commonly implicated in models of the onset of psychotic disorders. However, prospective studies investigating associations between biological markers of stress and the emergence of psychotic disorders are limited and inconclusive. One biological system proposed as the link between the psychological experience of stress and the development of psychosis is the Hypothalamic-Pituitary-Adrenal (HPA) axis. This paper summarizes and discusses evidence supporting a role for HPA-axis dysfunction in the early phase of schizophrenia and related disorders.

METHOD

A selective review of psychiatric and psychological research on stress, coping, HPA-axis, the hippocampus and psychotic disorders was performed, with a particular focus on the relationship between HPA-axis dysfunction and the onset of psychotic disorders.

RESULTS

Individual strands of past research have suggested that the HPA-axis is dysfunctional in at least some individuals with established psychotic disorders; that the hippocampus is an area of the brain that appears to be implicated in the onset and maintenance of psychotic disorders; and that an increase in the experience of stress precedes the onset of a psychotic episode in some individuals. Models of the onset and maintenance of psychotic disorders that link these individual strands of research and strategies for examining these models are proposed in this paper.

CONCLUSIONS

The current literature provides some evidence that the onset of psychotic disorders may be associated with a higher rate of stress and changes to the hippocampus. It is suggested that future research should investigate whether a relationship exists between psychological stress, HPA-axis functioning and the hippocampus in the onset of these disorders. Longitudinal assessment of these factors in young people at 'ultra' high risk of psychosis and first-episode psychosis cohorts may enhance understanding of the possible interaction between them in the early phases of illness.

Melanin-concentrating hormone (MCH) reverts the behavioral effects induced by inescapable stress

The aim of this work was to investigate if MCH modifies the feeding and freezing responses in rats exposed to stressful stimuli. We used a basic version of contextual fear, where one group of rats were placed in a novel environment and two different groups were exposed to footshock paradigms, one of them escapable and the other one inescapable. At the end of each treatment, freezing and feeding were measured. Only the animals exposed to inescapable footshock paradigm showed significant increase in the food intake and freezing behavior in comparison to the control animals. The MCH administration (intra-hippocampal or intra-amygdaline) reverted these effects elicited by inescapable footshock. Results presented in this paper lead us to the assumption that the anxiolytic effect of the peptide is responsible for the reversion of the IS effects.

Allostatic load and clinical risk as related to sense of coherence in middle-aged women

OBJECTIVE

To investigate how physiologic dysregulation, in terms of allostatic load and clinical risk, respectively, relates to sense of coherence (SOC) in women with no previously diagnosed pathology.

METHODS

At baseline, 200 43-year-old women took part in a standardized medical health examination and completed a 3-item measure of SOC, which they completed again 6 years later. According to data from the medical examination, two different measures of physiologic dysregulation were calculated: a) a measure of allostatic load based on empirically derived cut points and b) a measure of clinical risk based on clinically significant cut points.

RESULTS

In line with the initial hypotheses, allostatic load was found to predict future SOC, whereas clinical risk did not. In addition to baseline SOC and nicotine consumption, allostatic load was strongly associated with a weak SOC at the follow-up.

CONCLUSIONS

The better predictive value of allostatic load to clinical risk indicates that focusing solely on clinical risk obscures patterns of physiologic dysregulation that influence future SOC.

Revalidation of the postpartum stress scale

AIMS AND OBJECTIVES

The purpose of this study was to test further and validate the postpartum stress scale developed for Taiwanese women.

BACKGROUND

The postpartum stress scale was developed to measure postpartum stress in Taiwanese women. However, over the last decade, the social context in Taiwan has changed and several items in the scale needed to be re-examined.

DESIGN

Non-experimental quantitative research with repeated measures at the first and fifth week of the postpartum period was conducted for this study.

METHODS

A proportional stratified quota was used to sample from the 10 hospitals and six clinics with the highest birth rates in Kaohsiung, Taiwan. Participants were 505 and 518 postpartum women at each time point, respectively.

RESULTS

Factor analysis at two points in time identified three attributes of postpartum stress: (a) maternal role attainment, (b) lack of social support, and (c) negative body changes. The Cronbach's alphas at each time point were 0.94 and 0.92, respectively.

CONCLUSIONS

The results support the postpartum stress scale as a validated instrument that has been conceptualized, created, and tested with Taiwanese postpartum women.

RELEVANCE TO CLINICAL PRACTICE

This study was done in the hope that women experiencing specific postpartum stressors would be detected and subsequently helped by supportive nursing intervention that provides stressor-specific coping resources.

Neighbourhood and individual socioeconomic inequalities in smoking: the role of physical neighbourhood stressors

OBJECTIVE

To explore the association between physical neighbourhood stressors and smoking, and the contribution of these stressors to neighbourhood and individual socioeconomic inequalities in smoking.

METHODS

Data were analysed of participants of the baseline measurement of the Dutch GLOBE study (1991), aged 20 years and older, who lived in 79 neighbourhoods of the city of Eindhoven (n = 9062). The neighbourhood socioeconomic environment was assessed from aggregated self reported information of participants' education and occupation level, and employment status. Neighbourhood stressors included were the physical quality (decay), required police attention, noise pollution from traffic, and population density in neighbourhoods. Current smokers were distinguished from previous and never smokers.

RESULTS

Compared with those living in the most advantaged neighbourhoods, residents living in the socioeconomically most disadvantaged neighbourhoods were more likely to smoke (adjusted for age, sex, education, occupation, and employment status) (OR = 1.24, 95% CI 1.05 to 1.46). An increase in a summary neighbourhood stressor score was associated with smoking, independently of the neighbourhood socioeconomic environment (OR = 1.57, 95% CI 1.11 to 2.21, in the neighbourhoods with the highest stress score). Adjustment for the score substantially reduced the odds ratio for living in the socioeconomic most disadvantaged neighbourhoods (OR = 1.03, 95% CI 0.84 to 1.28, for those in the most disadvantaged neighbourhoods). Neighbourhood stressors contributed 10% to the increased probability of smoking in the lowest educated persons.

CONCLUSIONS

Physical neighbourhood stressors are related to smoking and contribute substantially to neighbourhood inequalities in smoking over and above individual level characteristics.

Dissociation of analgesic and hormonal responses to forced swim stress using opioid receptor knockout mice

Exposure to stress triggers hormonal and behavioral responses. It has been shown that the endogenous opioid system plays a role in some physiological reactions to stress. The opioid system was described to mediate analgesia induced by mild stressors and to modulate the activation of the hypothalamic-pituitary-adrenal axis. Our study assessed the contribution of opioid receptors in stress-induced analgesia and adrenocorticotropic hormone (ACTH) and corticosterone release by a genetic approach. We performed a parallel analysis of mice deficient in mu, delta, or kappa opioid receptors, as well as of triple opioid receptor knockout mice, following exposure to a mild stress (3-min swim at 32 degrees C). In wild-type mice, stress elicited an increase in jumping latency on the hot plate, which was influenced by gender and genetic background. This analgesic response was reversed both by naloxone and by the triple mutation, and decreased in mu and delta opioid receptor knockout females. In wild-type females, stress also delayed front- and hindpaw behaviors in the hot plate test and increased tail-flick latency in the tail immersion test. Opioid receptor deletion however did not affect these stress responses. In addition, stress produced an increase in ACTH and corticosterone plasma levels. This endocrine response remained unchanged in all mutant strains. Therefore our data indicate that, under our stress conditions, the endogenous opioid system is recruited to produce some analgesia whereas it does not influence hypothalamic-pituitary-adrenal axis activity. This implies that brain circuits mediating analgesic and hormonal responses to stress can be dissociated.

Stress and stressors of the early phases of the Persian Gulf War

Soldiers who deployed to Saudi Arabia in support of Operation Desert Shield were exposed to a wide variety of stressors. These stressors from the pre-combat phase of the deployment undoubtedly affect the current health of Gulf War veterans, but the exact mechanisms and linkages are not known. This article examines the nature of those stressors and possible effects on later health of veterans.

The four-dimensional stress test: psychological, sympathetic-adrenal-medullary, parasympathetic and hypothalamic-pituitary-adrenal responses following inhalation of 35% CO2

BACKGROUND

Hypercapnia is a threat to homeostasis and results in neuroendocrine, autonomic and anxiogenic responses. The inhalation of carbon dioxide (CO2) may, therefore, provide a good paradigm for exploring the pathways by which stress can lead to increased susceptibility to ill-health through physiological and psychological stress reactivity. The current study was designed, therefore, to assess the psychological and physiological responses to the inhalation of CO2.

METHODS

Healthy participants (N = 24) inhaled a single vital capacity breath of a mixture of CO2 (35%) and oxygen (65%). Blood pressure and heart rate were recorded for 5 min before and after the test and blood and saliva samples were taken immediately before and 2, 10, 20 and 30 min post-inhalation for the measurement of noradrenaline, salivary and serum cortisol and salivary alpha amylase. In addition, psychosomatic symptoms were recorded immediately before and after the test. The same protocol was repeated 4-6 weeks later at the same time of day.

RESULTS

A single inhalation of CO2 increased blood pressure, noradrenaline, salivary alpha amylase and psychosomatic symptoms, but decreased heart rate at both testing sessions. Analyses of salivary cortisol data revealed that 70% of the sample could be reliably classified as either responders (i.e. demonstrated a post-CO2 cortisol increase) or non-responders (i.e. responded with a decrease or no change in cortisol following CO2) at both test sessions. Responders also perceived the test to be more aversive than non-responders.

CONCLUSIONS

Inhalation of 35% CO2 reliably stimulated the key mechanisms involved in the human stress response. The inter-individual differences in the reactivity of the hypothalamic-pituitary-adrenal axis were also related to differences in the perception of the test.

The involvement of the vasopressin system in stress-related disorders

The neuropeptide arginine vasopressin (AVP) is released within distinct brain areas upon appropriate stimulation, including stressful challenges. Following its predominantly dendritic release, AVP triggers a variety of receptor-mediated effects related to behavioral and neuroendocrine regulation. Antagonist treatment together with other sophisticated loss-of-function and gain-of-function approaches provide evidence for a multiple involvement of V1a and V1b receptor subtypes in stress-related behavior and disorders, including anxiety disorders, comorbid depression and their neuroendocrine concomitants. Conversely, in the high versus low anxiety (HAB/LAB) rat model, the phenotype of extreme trait anxiety is associated with a polymorphism-driven overexpression of AVP in the hypothalamic paraventricular nucleus. This overexpression of AVP might be considered a final common pathway of anxiety-related behavior. The capability of both responding to stressful stimuli and mediating genetic polymorphisms makes the central release of AVP a key process for converging (i.e., environmentally and genetically driven) behavioral regulation. Polymorphisms in the promoter structures of the AVP gene and AVP receptor genes, underlying differences in gene expression, thus contribute to individual variation in behavior as well as to psychopathology, making genes of the brain AVP system and their products a promising target for therapeutic interventions.

A confirmatory factor analysis of situation-specific Norbeck Social Support Questionnaire items

BACKGROUND

Situation-specific social support, measured by comparably worded Norbeck Social Support Questionnaire (NSSQ) items, holds promise in the development of context-specific theories at the practice level. However, psychometric work on situation-specific NSSQ items is lacking.

OBJECTIVE

The aim of this study was to explore the statistical parameters of situation-specific NSSQ items (affect, affirmation, and aid).

METHODS

Using data (N = 154) collected for a larger study, the parameters of three LISREL models were estimated by the generally weighted least squares method using an asymptotic covariance matrix.

RESULTS

The modified two-factor model was accepted (chi2 = 11.54, df = 7, p < or = .12). Overall, parameter estimates suggest that, in this research context, two situation-specific items (affirmation and aid) measure unique dimensions of social support.

CONCLUSIONS

In this instance, situation-specific affirmation and aid items measure unique dimensions of support. Guided by strong theory, investigators should develop situation-specific items based on the original NSSQ items.

The effectiveness of a 15 minute weekly massage in reducing physical and psychological stress in nurses

OBJECTIVE

To investigate the effectiveness of massage therapy in reducing physiological and psychological indicators of stress in nurses employed in an acute care hospital.

DESIGN

Randomised controlled trial.

SETTING

Acute care hospital in Queensland.

SUBJECTS

Sixty nurses were recruited to the five week study and randomly assigned to two groups.

INTERVENTION

A 15 minute back massage once a week. The control group did not receive any therapy.

MAIN OUTCOME MEASURES

Demographic information, a life events questionnaire and a brief medical history of all participants was completed at enrolment. Physiological stress was measured at weeks one, three and five by urinary cortisol and blood pressure readings. Psychological stress levels were measured at weeks one and five with the State-Trait Anxiety Inventory (STAI).

RESULTS

Differences in the change in urinary cortisol and blood pressure between the two groups did not reach statistical significance. However, STAI scores decreased over the five weeks for those participants who received a weekly massage. The STAI scores of the control group increased over the five week period. These differences between the groups were statistically significant.

CONCLUSION

The results of this study suggest that massage therapy is a beneficial tool for the health of nurses as it may reduce psychological stress levels. It is recommended that further large studies be conducted to measure the symptoms of stress rather than the physiological signs of stress in nurses.

Measuring wellness among resident physicians

Requirements to include professionalism in residency curricula have generated a substantial body of literature concerning the environments that fail to nurture professionalism. Local and national surveys provide evidence that a high prevalence of depersonalization and emotional exhaustion exists among residents and that clinical practice is impaired as a result of these factors. A group of 34 residents from ten residency programmes participated in the psychometric testing of a resident wellness assessment instrument that can be rapidly administered, scored, and interpreted. The Brief Resident Wellness Profile is composed of a Mood faces graphical rating item and a six-question subscale. The six-item subscale had good reliability (alpha = 0.83; r = 0.84), convergent validity (r = 0.63), discriminant validity (r = -0.37), and concurrent validity ( p = 0.007). The Mood faces item had good convergent validity (r = 0.66), discriminant validity (r = -0.71), and concurrent validity ( p = 0.008). The Brief Resident Wellness Profile appears to be a reliable and valid instrument that measures residents' sense of professional accomplishment and mood and can be rapidly administered, scored, and interpreted.

Transforming growth factor-α induces sex-specific neurochemical imbalance in the stress- and memory-associated brain structures

Transforming growth factor-alpha (TGFalpha) is a well-known regulator of many developmental processes. However, its role in adult nervous system is yet unclear. Studies have shown that TGFalpha can regulate stress and memory behavior in adult mice. When TGFalpha is reduced in Waved-1 (Wa-1) mutant mice, the stress response and memory are impaired predominantly in males and only after puberty. To determine the neurochemical changes resulting from the reduced TGFalpha levels that could explain the reported behavioral outcomes, biogenic amine and amino acid levels were determined in the brain regions associated with stress and memory. Interestingly, sex-specific alterations in neurochemical levels were detected, including elevated noradrenaline and reduced glutamate levels in striatum of Wa-1 males, increased noradrenaline and reduced serotonin metabolite levels in hippocampus of Wa-1 females, reduced serotonin metabolite levels in cortex and amygdala of Wa-1 females, and reduced noradrenaline, dopamine, serotonin, glutamate and glycine levels in hypothalamus of Wa-1 females compared to their respective controls. Increased dopamine turnover in cortex and reduced dopamine and serotonin turnover in amygdala were observed in both male and female Wa-1 mice. The data indicate sex-specific alterations of specific neurochemicals as a result of reduced TGFalpha expression, which may underlie sex-dependent stress response and memory impairment in Wa-1 mice.

High Cognitive Dietary Restraint Is Associated With Increased Cortisol Excretion in Postmenopausal Women

BACKGROUND

Cognitive dietary restraint (perceived ongoing effort to limit dietary intake to manage body weight) is common in women at all life stages. In young women, high dietary restraint has been associated with both increased excretion of cortisol (a stress hormone) and reduced bone mass. Whether this occurs in older women is unknown and is reported here for the first time.

METHODS

Postmenopausal women (49-75 years old) with high (n = 41) or low (n = 37) dietary restraint were compared to examine differences in urinary cortisol excretion, body composition assessed by dual-energy x-ray absorptiometry (bone mineral density, % body fat), dietary intake, anthropometrics, current exercise, and perceived stress.

RESULTS

Women with high or low dietary restraint did not differ in age, body mass index, waist-to-hip ratio, energy intake, perceived stress, current exercise, or measures of body composition. However, urinary cortisol excretion was higher in the high restraint group (248.2 +/- 61.7 nmol/d vs 204.3 +/- 66.1 nmol/d; p =.01). Multiple regression analysis indicated that restraint group (high or low) independently predicted 7.6% of the variance in cortisol excretion.

CONCLUSIONS

Postmenopausal women with high dietary restraint excrete more cortisol than do those with low restraint, suggesting that dietary restraint may be a source of stress. Although this was not associated with negative health effects in this sample, further investigation is warranted.

Initial physiological responses and perceived hyperarousal predict subsequent emotional numbing in pediatric injury patients

The present study tested the hypothesis that acute posttraumatic hyperarousal would lead to the development of emotional numbing (EN) symptoms in a pediatric injury population. Eighty-two youths aged 8-18 years were recruited from the emergency department of a Midwestern children's hospital. Heart rate was recorded from emergency medical services reports and a 12-hour urine collection was initiated upon admission. Six weeks and 6 months later, depression and PTSD symptoms were assessed. Initial heart rate and urinary cortisol levels predicted 6-week and 6-month EN after controlling for concurrent depression, avoidance, and reexperiencing symptoms and 6-week hyperarousal symptoms. These findings provide empirical support for prior hypotheses concerning the development of PTSD symptoms over time.

Melanin-concentrating hormone-1 receptor modulates neuroendocrine, behavioral, and corticolimbic neurochemical stress responses in mice

Repeated exposure to stressful conditions is linked to the etiology of affective disorders. The melanin-concentrating hormone-1 receptor (MCHR1) may be a novel mechanism that is involved in the modulation of stress responses and affective states. The role of MCHR1 in neuroendocrine, behavioral, and neurochemical stress, and anxiety-related responses was examined by monitoring the effects of melanin-concentrating hormone (MCH) and the selective MCHR1 antagonist, GW3430, in inbred C57Bl/6NTac and MCHR1-knockout (KO) and wild-type (WT) mice. Intracerebroventricular injection of MCH increased plasma corticosterone, and produced anxiety-related responses in the elevated plus maze. The selective MCHR1 antagonist, GW3430, blocked the neuroendocrine and behavioral effects of MCH and produced anxiolytic-like effects by itself in animal models of anxiety. Moreover, KO mice had an anxiolytic-like phenotype in behavioral models of anxiety, and GW3430 had anxiolytic-like effects in WT, but not KO mice. Lastly, stressor-evoked acetylcholine release within the prefrontal cortex of inbred and WT mice, but not KO mice, was blocked by GW3430. We show that MCH elicits anxiety-like responses and that the effects of a selective MCHR1 antagonist and the phenotype of KO mice are consistent with anxiolytic-like action. Distinct behavioral, physiological, and neurochemical stress, and anxiety-related responses were selectively modulated by the MCHR1, and these actions may involve corticolimbic regulation of stress responsivity and anxiety.

Behavioural and hormonal responses to predation in female chacma baboons (Papio hamadryas ursinus)

In humans, bereavement is associated with an increase in glucocorticoid (GC) levels, though this increase can be mitigated by social support. We examined faecal GC levels and grooming behaviour of free-ranging female baboons to determine whether similar effects were also evident in a non-human species. Females who lost a close relative experienced a significant increase in GC levels in the weeks following their relative's death compared with the weeks before, whereas control females showed no such increase. Despite the fact that females concentrate much of their grooming on close kin, females who lost a close female relative did not experience a decrease in grooming rate and number of grooming partners; instead, both grooming rate and number of grooming partners increased after a relative's death. While the death of a close relative was clearly stressful over the short term, females appeared to compensate for this loss by broadening and strengthening their grooming networks. Perhaps as a result, females' GC levels soon returned to baseline. Even in the presence of familiar troop-mates and other relatives, females experienced a stress response when they lost specific companions, and they apparently sought to alleviate it by broadening and strengthening their social relationships.

Development and validation of the Infertility Self-Efficacy scale

OBJECTIVE

To develop and validate a scale of perceived self-efficacy for people coping with infertility treatment.

DESIGN

Self-efficacy scale development involved: [1] item generation with medical experts in reproductive health; [2] a principal components analysis with varimax rotation to identify underlying item components; [3] test-retest reliability and construct (convergent and discriminant) validity with infertility patients, who were administered the Infertility Self-Efficacy (ISE) scale with other measures; and [4] expert acceptability, as determined by reproductive health professionals.

SETTING

Recruitment at a fertility center, a national infertility organization, and medical trials web pages.

PATIENT(S)

A total of 213 participants (159 women; 54 men) with a diagnosis of infertility in the past 2 years were recruited for the various study phases.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Participants' infertility self-efficacy was assessed with an online assessment battery using the ISE scale; comparison mental health measures assessed current levels of fertility problem distress, perceived stress, and coping style. Reliability, validity, and component structure of the ISE was assessed.

RESULT(S)

Measurement development yielded a brief 16-item ISE scale that taps an infertility patient's perception about his or her ability to engage in a set of cognitive, emotional, and behavioral skills related to the medical treatment of infertility. The single component of "cognitive/affect regulation" suggests this core set of skills is relevant to successfully managing the experience of infertility. The ISE correlations with comparison mental health measures were as expected, suggesting good convergent and discriminant validity.

CONCLUSION(S)

The ISE scale appears to be a reliable and valid measure of an individual's self confidence in areas related to health promotion during infertility treatment. Assessing an infertility patients' self-efficacy with the ISE may be useful in clinical research and as a counseling tool to help guide patients in actively managing their fertility treatment.

PTSD and the HPA axis: differences in response to the cold pressor task among individuals with child vs. adult trauma

Hypothalamic pituitary adrenal (HPA) axis and subjective stress response to a cold-water immersion task, the cold pressor task (CPT), in individuals (N=89) with post-traumatic stress disorder (PTSD) were examined. All tests were conducted at 08:00h after an overnight hospital stay. Plasma adrenocorticotrophin hormone (ACTH), cortisol, and subjective stress were examined at baseline and five post-task time points in controls (n=31), subjects with PTSD as a result of an index trauma during childhood (i.e. before age 18; n=25), and subjects with PTSD as a result of an index trauma as an adult (n=33). Approximately, 50% of individuals in both trauma groups were alcohol dependent, and the impact of this comorbidity was also examined. Subjects with PTSD, regardless of age of index trauma, had a less robust ACTH response as compared to controls. Regardless of the presence or absence of comorbid alcohol dependence, subjects with childhood trauma had lower cortisol at baseline and at all post-task measurement points and did not demonstrate the decrease in cortisol over the course of the 2h monitoring period seen in subjects with adult index trauma and controls. The findings reveal differences in the neuroendocrine response to the CPT in individuals with PTSD compared to control subjects, and differences in PTSD subjects when examined by age of index trauma.

Socioeconomic status is associated with stress hormones

OBJECTIVE

We assess whether socioeconomic status (SES) is associated with basal levels of cortisol and catecholamines and determine if any association between SES and these hormones can be explained (is mediated) by behavioral, social, and emotional differences across the SES gradient.

METHODS

One hundred ninety-three adult subjects, including men and women and whites and African-Americans, provided 24-hour urine catecholamine samples on each of 2 days and seven saliva cortisol samples on each of 3 days beginning 1 hour after wake-up and ending 14 to 16 hours later. Values for both hormones were averaged across days to obtain basal levels.

RESULTS

Lower SES (income and education) was associated with higher levels of cortisol and epinephrine and marginally higher levels of norepinephrine. These associations were independent of race, age, gender, and body mass. Low SES was also associated with a greater likelihood of smoking, of not eating breakfast, and with less diverse social networks. Further analyses provided evidence consistent with the hypothesis that these behavioral and social variables mediate the link between SES and the three stress hormones.

CONCLUSIONS

Lower SES was associated in a graded fashion with higher basal levels of cortisol and catecholamines. These associations occurred independent of race, and the data were consistent with mediation by health practices and social factors.

Reducing parenting stress in families with irritable infants

BACKGROUND

Caring for an infant with unexplained, persistent crying is one of the most stressful events for new parents. Infant irritability, also referred to as infantile colic, occurs in 10-25% of all infants and is the most common parental concern reported in the first year of life.

OBJECTIVE

The aim of this study was to evaluate the effectiveness of a home-based nursing intervention in reducing parenting stress in three groups of families with irritable infants, using data from a larger evaluation study.

METHODS

A two-site, randomized clinical trial was conducted with 121 infants and their parents. Infants were randomized to a treatment or a control group. A third group of infants (n = 43) was added as a posttest-only comparison. The level of parenting stress was measured by the Parenting Stress Index (PSI) at baseline, after the 4-week intervention, and at the 8-week follow-up visit.

RESULTS

A repeated measures analysis of variance (ANOVA) was used to compare the two groups across the three time points (baseline, immediately after the 4-week intervention, and at the 8-week follow-up visit). The results revealed a reduction in total parenting stress over time for both the treatment and control groups. Mothers in the treatment group reported reduced parenting stress on the parent-child dysfunctional interaction subscale (p = .04). Total parenting stress scores were found to be significantly higher for mothers in the posttest-only group (p = .009).

CONCLUSION

Initial parenting stress levels were high in all participants. Parent feedback at the exit interview indicated that the nurse visits for data collection were also viewed as helpful in reducing the stress level associated with parenting these irritable infants. This home-based program was perceived as helpful in improving the interactions between parents and their irritable infants.

Social stress is as effective as physical stress in reinstating morphine-induced place preference in mice

RATIONALE

Relapse to drug-seeking in abstinent heroin addicts and reinstatement in experimental animals are observed when exposed to drug-associated stimuli or cues, the drug itself, and stressful events. It has been shown that footshock-induced stress increases the rewarding effects of opiates, delays extinction, and induces the reinstatement of drug-seeking. However, the effects of social stress on the reinstatement of opiate-seeking after extinction has not been studied.

OBJECTIVES

The role of physical (restraint and tail pinch) and social (social defeat) stressors on the reinstatement of morphine-induced conditioned place preference (CPP) was evaluated.

METHODS

Adult male OF1 mice were conditioned with 10, 20, or 40 mg/kg of morphine or saline. Only morphine-conditioned animals acquired CPP. All mice underwent extinction sessions until the CPP was extinguished. Then, the effects of physical or social stress on the reinstatement of CPP were evaluated. Morphine- and saline-conditioned animals were exposed to the respective stressor or control stress condition immediately or 15 min before reinstatement tests. In experiment 1, animals underwent restraint for 15 min. In experiment 2, animals were exposed to tail pinch or placed in a cage without any manipulation for 15 min. In experiment 3, animals performed an agonistic encounter with an isolated or anosmic mouse or were placed in a cage without any social contact or manipulation.

RESULTS

Restraint, tail pinch, and social defeat in an agonistic encounter with an isolated mouse produce the reinstatement of CPP in morphine-conditioned animals.

CONCLUSIONS

These data demonstrate that social stress is as effective as physical stress in reinstating morphine-seeking.