Animals show a great variety in physiological and behavioural responses to stressors. These responses are often bimodally distributed within populations and show consistency on an individual level over time and across situations, which in terrestrial vertebrates have been identified as proactive and reactive stress coping strategies. Proactive animals show lower cortisol responses, higher sympathetic activation and brain serotonergic activity compared to reactive animals. Behaviourally, proactive animals are more aggressive, more active in avoiding stressors, they form routines and show fewer cases of conditioned immobility compared to reactive animals. Our aim has been to reveal if such stress coping strategies exist in fish. Our results show that rainbow trout with high (HR) or low (LR) cortisol responses to stressors differs in sympathetic activation and brain serotonin turnover in the same manner as proactive and reactive mammals. HR fish showed less locomotor activity when reared in large groups (30 individuals) compared to LR fish. When reared in isolation there were no differences between HR and LR fish when exposed to stressors within a familiar environment. The adaption of a proactive coping style among reactive coping individuals when they are challenged within a familiar environment has previously been shown to be distinction between proactive and reactive coping mammals. However, when they were transferred to unfamiliar environments a behavioural difference between the two lines was observed indicating different stress coping strategies akin to those described in mammals. Finally, we observed a consistency over time in the cortisol response of an unselected line of rainbow trout. Fish from this line also demonstrated a correlation between behavioural responses to different stressors. However, there was no apparent connection between these behavioural responses and the cortisol response. Overall, the results of this thesis have strengthened the hypothesis that different stress coping strategies exist in teleost fish.

As our long-term companions, dogs’ communication with us is perhaps the most developed of all human- animal ones. This study was aimed to investigate breed differences of German Shepherds and Labradors in dog-human communication. This was obtained through two tests: a problem-solving task and a pointing test. These two tests target both directions of communication: how much dogs understand and respond to the pointing and how they communicate with humans when facing a problem. Additionally, hair cortisol was measured in the dogs and dog owners filled a behavioural questionnaire (C-BARQ). The main breed difference I found was that Labradors performed better in both tests. I also found that the latency of the dogs’ choices in the pointing test correlated with many factors, e.g. they chose quicker when: choosing correctly, when they had many physical contacts with the experimenter in the problem-solving task, when they were more intense, energetic dogs, when they had higher hair cortisol levels and when they had a confident body posture. This indicates that the latency of choice could depend on the confidence of the dog and on the trust in the experimenter as well as on energy level and focus ability. Overall, this study revealed a limited amount of breed differences, compared to a parallel study on Labrador types (hunting and show dogs), showing that intra-breed differences can be more important than inter-breed ones on a behavioural level.

Pregnancy is a time of alternating states of inflammation. The establishment of pregnancy is marked by controlled inflammation and transition toward an anti-inflammatory state for much of the gestational period before returning to an inflammatory state at the onset of labor. Stress and depression trigger the HPA Axis to produce cortisol and levels are maintained in a state of elevation during pregnancy and continue to rise before parturition. The aim of this research was to explore the relationship of gestational age at delivery with mid-pregnancy levels of cytokines, stress and depression. Participant samples (N = 122) were collected between 16 and 26 weeks gestation and analyzed for 14 cytokines using a bead-based multiplex assay. Plasma cortisol was also measured along with demographic variables and measures of perceived stress and dysphoric mood. Results of Pearson's correlations showed that gestational age at delivery was significantly inversely correlated with pro-inflammatory cytokine IFN-ã and anti-inflammatory IL-13. A significant positive correlation was noted with the number of pregnancies in the obstetric history and pregnancy length. Both cortisol and stress were not correlated with gestational age at delivery.

Across three studies, the role that testosterone plays in how individuals respond psychologically, behaviorally, and physiologically to status challenges was investigated. Preliminary Studies 1 focused on how testosterone related to physiological and psychological responses to a medical threat. Preliminary 2 replicated the psychological effects observed in Preliminary Study 1. Study 3 examined how experimentally manipulated testosterone levels corresponded to responses to a socially judged physical endurance task across all three response types. Preliminary Study 1 examined the relationship between testosterone and conscious evaluations of and physiological reactions to a health threat. Participants were diagnosed with a fictitious enzyme deficiency before rating their views of the deficiency, as well as providing saliva samples before and after diagnosis. Basal testosterone was negatively associated with the belief that one actually had the deficiency, despite the diagnosis. Testosterone was also positively associated with a greater increase in salivary cortisol levels following the diagnosis. Self-reported anxiety was found to be positively associated with evaluating the deficiency as threatening. Preliminary Study 2 replicated the findings observed in Preliminary Study 1 regarding conscious evaluations of a medical threat. Using the same experimental manipulation, testosterone was again found to be negatively associated with ratings of the enzyme deficiency. In Preliminary Study 2, high levels of testosterone were associated with viewing the deficiency as less serious and viewing medical conditions, in general, as less threatening. Study 3 used a transdermal administration procedure to artificially elevate individuals’ testosterone levels before completing a socially evaluated task. Participants who received the testosterone administration showed greater physiological responses to the task, including cardiovascular responses and cortisol responses, compared to the placebo group. Unlike Preliminary Studies 1 and 2, Study 3 did not show any effect of testosterone on conscious evaluations of the task nor behavioral measures of performance. Taken together, the three studies highlight the different ways in which testosterone is related to responding to social threats. Testosterone appears to be associated with mobilizing physiological systems to theoretically facilitate behavioral responses to status threats. Testosterone also appears to be negatively associated with consciously evaluating certain types of threats. / text

Relationship conflict is robustly linked to negative physiological responses that have serious implications for partners’ overall physical health. The link between relationship conflict and physiological reactivity, however, has been studied almost exclusively in a laboratory setting. The first aim of this study was to assess the link between conflict and physiological function in couples’ home environments. Newlywed spouses reported occurrences of marital conflict in a daily diary and concurrently provided morning and evening saliva samples for the calculation of daily diurnal cortisol slopes. Spouses experienced less steep (i.e., less healthy) diurnal cortisol slopes on days of greater marital conflict. The second aim of this study was to examine whether spouses’ connections with close others outside their marriages (i.e., quantity and quality of perceived network support) moderate physiological responses to marital conflict. Whereas the quantity of network support did not influence spouses’ responses to conflict, the quality of spouses’ network support attenuated the association between daily marital conflict and diurnal cortisol. Specifically, whereas those spouses who were less satisfied with their network support experienced less steep diurnal cortisol on days of greater marital conflict, those spouses who were more satisfied with their network support exhibited no effects of daily marital conflict on diurnal cortisol. Implications for maintaining quality social relationships outside a marriage are discussed. / text

Increasing evidence illustrates an involvement of stress in a large variety of physical and mental illness. Together with the evolutionary development of the social behavior in humans, the traditional interpretations of the attachment theory and the social support theory underscores the importance of affection, belonging and appreciation for human well-being. Not only can an imbalanced stress system be the cause of severe pathological consequences, insufficient social contact can also hamper recovery. Frequent usage of animals in various settings steadily illustrates both physiological and psychological benefits on both the young and the old, the healthy and the ill. Through the study of neurobiological factors, with oxytocin as a central mediator of social behavior and its  impact in turn on the stress- and cortisol system, this paper examines the possibility of animals to function as social support. The potential of animals to reduce the suffering in patients with stress related psychiatric disorders, such as the highly frequent exhaustion disorder, human-animal interactions might offer a non-invasive complementary tool to current treatment methods.

In most adult animals, stress is generally thought to be detrimental to reproductive (sexual) function. However, in humans, there is a limited body of literature that indicates some stress can potentially be beneficial for sexual function. One theory is that there is an inverted U relationship between stress and sexual function with low and high levels of stress (or anxiety) causing an impairment of sexual response, while a moderate level of stress facilitates sexual arousal. This aim of this dissertation is to identify the mechanisms through which both acute and chronic stress may facilitate or impair sexual arousal in women. In particular, I examined the role of adrenal hormones, the autonomic nervous system (ANS), and psychological factors. To test these mechanisms, I measured cortisol, dehydroepiandrosterone sulfate (DHEAS), heart rate, distraction, and misattribution of arousal during stressful and sexual laboratory situations. Two of the studies examined the effects of acute stress, and the final study focused on chronic stress. Results indicated that acute stress is beneficial for genital arousal in women, and that the sympathetic branch of the ANS is the key mechanism involved in that relationship. High levels of chronic stress were found to significantly impair genital arousal compared to average levels of chronic stress. Increased levels of cortisol and distractions contributed to this effect. DHEAS did not appear to play a role in the relationship between stress and sexual arousal, and there was no evidence for misattribution of arousal. Neither acute nor chronic stress affected women’s subjective (psychological) arousal. Acute and chronic stressors affect sexual arousal in different ways and through separate mechanisms. The findings from these studies can inform treatment approaches for women with sexual arousal difficulties. / text

This paper describes two experiments, each of which investigated the impact of stress on human episodic memory. All participants watched narrated slide shows containing emotional and neutral information. Experiment 1 demonstrated that pre-learning exposure to a psychological stressor (the Trier Social Stress Test or "TSST"; Kirschbaum, Pirke & Hellhammer, 1993) preserved or enhanced memory for emotional aspects of the slide show, but impaired memory for neutral aspects of the slide show. Moreover, stress exposure disrupted memory for information that was visually and thematically central to the slide show. Memory for peripheral information, on the other hand, was unaffected by stress. Experiment 2 replicated these results and extended them to a similar paradigm, where participants viewed separate emotional and neutral slide shows, and saliva was tested for the stress hormones cortisol and norepinephrine. Similar to the results of Experiment 1, stress disrupted memory for the neutral slide show, but enhanced memory for the emotional slide show. Salivary cortisol levels at retrieval were negatively correlated with memory for the neutral slide show. These results are consistent with theories invoking differential effects of stress on brain systems responsible for encoding and retrieving emotional memories (the amygdala) and non-emotional memories (e.g. the hippocampal formation, frontal cortex), and inconsistent with the view that memories formed under high levels of stress are qualitatively the same as those formed under ordinary emotional circumstances. These data, which are also consistent with results obtained in a number of studies using animals and humans, have implications for the traumatic memory debate and theories regarding human memory.

Introduction: Blood- and injection phobia is an anxiety disorder with a prevalence of approximately 3-5% in the general population. The etiology is often a combination of genetic factors and a conditioning experience. The symptoms of blood- and injection phobia are dizziness, confusion, nausea, epigastria discomfort, anxiety and sometimes panic attacks when receiving injections, seeing blood or having a blood sample taken. Unique for this specific phobia is the high probability of fainting when the phobic situation is encountered if there is no possibility to escape or to avoid the stimuli. During pregnancy and labor, women with blood- and injection phobia are exposed to most of their fears and they therefore find themselves in anxiety-ridden situations. Stress and anxiety during pregnancy is known to be risk factors for adverse obstetric and neonatal outcomes. Studies have shown an altered hypothalamic-adrenal-pituitary axis in women with stress or/and anxiety during pregnancy and increased cortisol concentrations can imply negative consequences for the unborn child. Cognitive behavioral therapy (CBT) is known to be effective in treating specific phobias such as blood- and injection phobia. Aim: The prevalence, obstetric and neonatal consequences, impact on the hypothalamic adrenal-pituitary axis and treatment aspects of blood- and injection phobia in a pregnant population have not been investigated before. The aims of this thesis were to study each of these phenomena. Material and methods: During 2005 a total of 1606 pregnant women were approached at their first visit in an antenatal care clinic in the southeast region in Sweden. They were asked to complete the “Injection Phobia Scale-Anxiety” questionnaire. All women who scored ≥ 20 on the “Injection Phobia Scale-Anxiety” questionnaire (N=347), were interviewed and either diagnosed for blood- and injection phobia or dismissed. In total, 110 women were diagnosed as having blood- and injection phobia. Among the women who scored <20 on the “Injection Phobia Scale-Anxiety” questionnaire, 220 women were randomly stratified for age and parity as a control group. The women in the study population answered questionnaires in gestational week 25, 36 and postpartum concerning symptoms of blood- and injection phobia, depression and anxiety. Samples of cortisol in the saliva were collected in the morning and evening in gestational week 25 and 36 in both groups of pregnant women. The medical records from the antenatal care visits, the delivery and postpartum check-up was used to collect data of importance. A treatment study was conducted using a two session cognitive behavioral therapy in a group of pregnant woman with blood- and injection phobia. Results: The prevalence of blood- and injection phobia is 7 % in a pregnant population. Pregnant women with blood- and injection phobia stated more often a fear of childbirth (p<0.001) and were more frequently delivered by elective cesarean section (p=0.032). The incidence of having a baby diagnosed with a complication (p=0.001) was also higher among these women. The women with blood- and injection phobia had increased cortisol concentrations in the saliva compared to the healthy controls (p=0.014). A two-session CBT in group for pregnant women with blood- and injection phobia reduced phobic (p<0.001) anxiety (p<0.001) and depressive (p<0.001) symptoms during pregnancy. Conclusions: Blood- and injection phobia during pregnancy is rather common. Pregnant women with blood- and injection phobia are more likely to be delivered by elective cesarean section and having a baby born with a complication compared to women not suffering from this specific phobia. Untreated blood- and injection phobia during pregnancy increases salivary cortisol concentrations indicating an altered hypothalamic-adrenal-pituitary axis during these weeks of pregnancy. To enhance psychological well being in pregnant women with blood- and injection phobia a two-session program providing CBT for groups of pregnant women is valuable and produces stable results for at least 3 months after delivery.

Background: An important role has been suggested for tissue-specific glucocorticoid metabolism in the development of obesity and its complications. 11ß hydroxysteroid dehydrogenase 1 (11ßHSD1) is an enzyme that catalyzes the interconversion of biologically inactive cortisone to active cortisol, thereby regulating its access to glucocorticoid receptors in target tissues. Indeed, an unfavorable metabolic outcome has been associated with increased 11ßHSD1 gene expression and activity in adipose tissue and liver in humans and rodents. Cortisol is an important regulator of phosphoenolpyruvate carboxykinase (PEPCK) a key enzyme in gluconeogenesis and lipid metabolism. In rodents, overexpression of PEPCK in adipose tissue leads to adiposity and increased fatty acid re-esterification. In human obesity, PEPCK has been positively associated with body fat, total cholesterol levels, and plasma triglycerides. However, few studies have addressed the putative reversibility of peripheral cortisol levels and disturbed fatty acid homeostasis that may accompany weight loss. The aim of this thesis was to investigate alterations in peripheral glucocorticoid metabolism in the context of obesity, and putative modulations of glucocorticoid metabolism in the context of weight changes in humans and rodents. Materials & Methods: 11ßHSD1 expression/activity in different adipose tissue depots and liver, the expression of genes involved in adipogenesis and fatty acid homeostasis, and serum levels of adipose tissue-derived adipokines were investigated in severely obese women before and after surgically induced weight loss. The same parameters were measured in female Sprague-Dawley rats fed on high-fat and control diets. Results: In severely obese women, 11ßHSD1 expression was higher in subcutaneous adipose tissue (SAT), while 11ßHSD1 activity and PEPCK expression were higher in the omental depot. In a multivariate analysis, SAT 11ßHSD1 activity was an independent predictor for central fat accumulation. Hepatic 11ßHSD1 activity and levels of intra-abdominal fat storage correlated negatively, while 11ßHSD1 correlated positively with PEPCK in adipose tissue and liver. Weight loss after gastric bypass surgery was followed by significant and metabolically beneficial reductions in subcutaneous 11ßHSD1 and leptin gene expression, as well as reduced circulating leptin and increased adiponectin levels. In contrast, PEPCK gene expression did not change with weight loss. In rats, a high-fat diet did not affect body weight, but was associated with increased serum leptin and decreased adiponectin levels. Short-term, high-fat diet feeding resulted in the up-regulation of SAT 11ßHSD1 expression, while chronic feeding led to its significant down-regulation (compared with the control diet and short-term, high-fat feeding). Interestingly, hepatic 11ßHSD1 expression was constantly downregulated in rats that were fed a high-fat diet. Conclusions: Severe obesity in women was accompanied by a metabolically adverse increase of 11ßHSD1 in adipose tissue, with a concomitant decrease in the liver. Subcutaneous 11ßHSD1 was an independent predictor for central fat accumulation. As weight loss was followed by significant down-regulation of subcutaneous 11ßHSD1, we suggest that up-regulation of this enzyme was a consequence, rather than a cause of obesity. In rodents, a high-fat diet induced dynamic changes in 11ßHSD1 in SAT and liver, both being down-regulated after chronic high-fat feeding without altered weight. In summary, weight changes and alterations in fat and liver glucocorticoid metabolism are closely linked. Moreover, a high-fat diet significantly influences 11ßHSD1 expression/activity in adipose tissue and liver without affecting body weight.