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• Having more than 50 quick returns was associated with impaired everyday memory. • Short sleep duration was associated with impaired everyday memory. • Memory problems might affect both nurses' and patients' health and safety. • We recommend limiting the number of quick returns and promoting enough sleep. To investigate the relationship between self-reported everyday memory problems the last month, and: (a) shift work schedule, (b) night shifts and quick returns worked the last year, and (c) sleep duration the last month. In all, 1,275 nurses completed the Everyday Memory Questionnaire – revised, and answered questions about shift work exposure and sleep duration. We performed multiple linear regression analyses with memory score as dependent variable, and the shift work exposure variables as well as sleep duration as predictors, while adjusting for potential confounders. High exposure to quick returns (β =.10, p <.05) and short sleep duration (β =.10, p <.05) were both positively associated with memory problems, whereas shift work schedule, long sleep duration, night shift exposure, and low and moderate exposure to quick returns were not. Frequent insufficient time for rest between shifts as well as short sleep was associated with poorer everyday memory. [ABSTRACT FROM AUTHOR]

Abstract Objective We compared subjectively reported sleepiness and fatigue as well as causes and management strategies for combating sleepiness among pilots working in 2 different helicopter emergency medical services operating with different shift systems. Methods Pilots from the Norwegian Air Ambulance (NAA) and Christophorus Flugrettungsverein (CFV) in Austria participated. NAA performs flight missions 24/7, whereas at the time of the study the participating CFV bases did not fly after sunset. The pilots are on duty for 1 week in both services. NAA and CFV used an identical research protocol, including questionnaires about sleep, sleepiness (Epworth Sleepiness Scale and Karolinska Sleepiness Scale), coping strategies, and work-related causes of fatigue. Results CFV pilots kept busy, whereas NAA pilots slept and did physical exercise as strategies to prevent sleepiness. The majority in both groups used napping and coffee consumption as strategies. CFV pilots reported more frequently than NAA pilots that administrative duties and environmental factors were reasons preventing napping. Conclusion Some differences existed between the 2 pilot groups regarding strategies for managing sleepiness and causes that prevented pilots from napping. Pilots in both groups were healthy, physically active, and had normal Epworth Sleepiness Scale and Karolinska Sleepiness Scale scores. [ABSTRACT FROM AUTHOR]

Summary Sleep deprivation and time of day are both known to influence performance. A growing body of research has focused on how sleep and circadian rhythms impact athletic performance. This review provides a systematic overview of this research. We searched three different databases for articles on these issues and inspected relevant reference lists. In all, 113 articles met our inclusion criteria. The most robust result is that athletic performance seems to be best in the evening around the time when the core body temperature typically is at its peak. Sleep deprivation was negatively associated with performance whereas sleep extension seems to improve performance. The effects of desynchronization of circadian rhythms depend on the local time at which performance occurs. The review includes a discussion of differences regarding types of skills involved as well as methodological issues. [ABSTRACT FROM AUTHOR]

Abstract: The aim of this cohort study was to investigate factors that might cause a shift in morningness–eveningness personality. A large sample of Norwegian nurses (n =1144) participated in a longitudinal survey study about life- and work factors, symptoms of anxiety and depression, and habits such as smoking, caffeine- and alcohol consumption. A hierarchical regression analysis was employed to determine if these variables had predictive value concerning changes in morningness assessed with the Diurnal Type Scale (DTS) over a 24-month interval. The results showed that percentage of full time equivalent, having children (or having children move in), and female gender all predicted higher scores on the morningness scale over time. Also, factors such as number of night shifts during the past two years, whether the subject had started smoking and higher alcohol consumption by the subject all predicted lower scores on the morningness scale over time. [Copyright &y& Elsevier]

Summary: An impressive body of research has investigated whether sexual abuse is associated with sleep disturbances. Across studies there are considerable differences in methods and results. The aim of this paper was to conduct the first systematic review of this area, as well as to clarify existing results and to provide guidelines for future research. We conducted searches in the electronic databases PsycINFO and PubMed up until October 2010 for studies on sleep disturbances in sexually abused samples. Thirty-two studies fulfilled the inclusion criteria (reported empirical data, included sexually abused subjects, employed some form of sleep measurement, English language and published in peer reviewed journals). Across the studies included, sleep disturbances were widespread and more prevalent in sexually abused subjects as compared to in non-abused samples. Symptoms reported more frequently by sexually abused samples included nightmare related distress, sleep paralysis, nightly awakenings, restless sleep, and tiredness. Results were divergent with regards to sleep onset difficulties, nightmare frequency, nocturnal activity, sleep efficiency, and concerning the proportion of each sample reporting sleep disturbances as such. Potential sources of these divergences are examined. Several methodological weaknesses were identified in the included studies. In order to overcome limitations, future researchers are advised to use standardized and objective measurements of sleep, follow-up or longitudinal designs, representative population samples, large sample sizes, adequate comparison groups, as well as comparison groups with other trauma experiences. [ABSTRACT FROM AUTHOR]

Abstract: Nurses exposed to high nursing stress report no health complaints as long as they have high coping abilities. The purpose of this study was to investigate coping styles in relation to the health status and work environment of Norwegian and Dutch hospital nurses. This comparative study included a random sample of 5400 Norwegian nurses and a convenience sample of 588 Dutch nurses. Coping, health, and work environment were assessed by questionnaire in both samples and associations were investigated bivariately and multivariately. We found that active problem-solving coping was associated with the health and work environment of Norwegian nurses but not with the health and work environment of Dutch. Passive coping (avoiding problems or waiting to see what happens) was found to relate to poor general health, poor mental health, low job control, and low job support in both Norwegian and Dutch nurses. Improvements in the nursing work environment may not only result in better mental health, but may also reduce passive coping. [ABSTRACT FROM AUTHOR]

Summary: Shift work tolerance is a term describing the ability to adapt to shift work without adverse consequences. In this paper we systematically review literature published investigating the relation between individual differences such as age, gender, personality, morningness/eveningness as well as biological variables and different measures of shift work tolerance from 1998 till 2009. A total of 60 articles were included in this review, of which ten studies were classified as longitudinal, while the rest were classified as cross-sectional. Overall, the studies indicate that young age, male gender, low scores on morningness, high scores on flexibility and low scores on languidity, low scores on neuroticism, high scores on extraversion and internal locus of control and some genetic dispositions are related to higher shift work tolerance. More longitudinal studies, especially concerning personality, are needed to make conclusions about the predictive power of individual differences for shift work tolerance. [Copyright &y& Elsevier]

Abstract: This study aimed to investigate whether different personality variables were associated with shift work tolerance, and whether these potential associations were moderated by various types of shift work. The sample comprised 1505 nurses who worked either two or three rotating shifts. Personality traits were measured in terms of morningness, flexibility, languidity and hardiness. Morningness reflects the tendency to be alert relatively early in the morning and sleepy relatively early in the evening. Flexibility denotes the ability to both work and sleep at odd times of the day, while languidity concerns the tendency to become tired/sleepy when cutting down on sleep. Hardiness relates to resilience to stressful life events. The dependent variables in this study comprised of measures of insomnia, sleepiness, depression and anxiety. Hierarchical regression analyses, which controlled for demographic variables and work load, revealed that Morningness was significantly and negatively related to insomnia. The Morningness by Shift type interaction was overall significant for depressive symptoms. Morningness was near significantly associated with lower levels of depressive symptoms in three-shift workers, but unrelated to depressive symptoms in two-shift workers. Flexibility was associated with higher levels of depressive symptoms. Flexibility by Shift type interaction was significant for insomnia, indicating that flexibility was negatively associated with insomnia for three-shift workers and unrelated with insomnia for two-shift workers. Languidity was associated with higher levels of sleepiness, depressive and anxiety symptoms. Hardiness was associated with lower levels of all four dependent variables. [Copyright &y& Elsevier]

Summary: Circadian rhythm sleep disorders are common in clinical practice. The disorders covered in this review are delayed sleep phase disorder, advanced sleep phase disorder, free-running, irregular sleep–wake rhythm, jet lag disorder and shift work disorder. Bright light treatment and exogenous melatonin administration are considered to be the treatments of choice for these circadian rhythm sleep disorders. Circadian phase needs to be estimated in order to time the treatments appropriately. Inappropriately timed bright light and melatonin will likely worsen the condition. Measurements of core body temperature or endogenous melatonin rhythms will objectively assess circadian phase; however, such measurements are seldom or never used in a busy clinical practice. This review will focus on how to estimate circadian phase based on a careful patient history. Based on such estimations of circadian phase, we will recommend appropriate timing of bright light and/or melatonin in the different circadian rhythm sleep disorders. We hope this practical approach and simple recommendations will stimulate clinicians to treat patients with circadian rhythm sleep disorders. [Copyright &y& Elsevier]

Abstract: Objective: The purpose of this study is to prospectively examine the independent contribution of symptoms of insomnia on sick leave. Methods: We used a historical cohort design with 4 years of follow-up. Information on sick leave was obtained from Norwegian official registry data and merged with health information from the Hordaland Health Study in Western Norway, 1997 to 1999. Six thousand eight hundred ninety-two participants aged 40 to 45 years were assessed for self-reported symptoms of insomnia, sociodemographic factors, lifestyle behaviors, body mass index, symptoms of sleep apnea, anxiety, depression, as well as a range of somatic diagnoses, somatic symptoms, and pain. The outcome was the total number of sick days during a 4-year follow-up period, as registered in the official registries by the National Insurance Administration. Results: Overall, insomnia was found to be a significant predictor of sick leave [odds ratio (OR)=2.20; 95% confidence interval (CI), 1.77–2.74], and the effect remained significant when adjusting for possible confounders (OR=1.51; 95% CI, 1.19–1.94). The effect increased with longer durations of sickness leave. Conclusion: This is the first study to demonstrate that insomnia is an independent risk factor for long-term sick leave. [Copyright &y& Elsevier]

Abstract: There is ample evidence for the existence of an association between sleeplessness and worry. Not much is known, however, concerning the nature of this relationship. Therefore, a study was conducted investigating the causal relationship between sleeplessness and nocturnal worry. A 2×2 (Worry×Induced sleeplessness) analysis of covariance design was used. The first factor consisted of a subject variable defined by scoring either high or low on a trait measure of worry (the Penn State Worry Questionnaire) and the second factor consisted of 300mg caffeine or placebo. A total of 96 female undergraduate students participated. The dependent variables comprised measures of nocturnal worry (the Night-Time Thoughts Questionnaire) and subjective and objective sleep parameters. Overall, caffeine caused an increase in nocturnal worry and sleeplessness. A significant interaction effect occurred between Worry and Induced sleeplessness on one of the objective sleep parameters, but no other interaction effects were significant. The results suggest that worry may occur as an epiphenomenon of sleeplessness. [Copyright &y& Elsevier]

Abstract: We investigated the effects of the perfusion of γ-aminobutyric acidA antagonist bicuculline in the dorsal raphe nucleus, on brain 5-hydroxytryptamine level and on sleep. Perfusion of 25 and 50 μM bicuculline into the dorsal raphe nucleus dose-dependently increased dorsal raphe nucleus 5-hydroxytryptamine level during sleep and wakefulness. Frontal cortex 5-hydroxytryptamine level was not affected by either 25 or 50 μM perfusion. 25 μM bicuculline produced only minimal effects on sleep. 50 μM decreased rapid eye movement sleep, slow wave sleep 1 and 2 and increased waking. Sleep changes leveled out towards the end of the bicuculline perfusion despite serotonin levels were still elevated. This suggests that an adaptation mechanism may take place in order to counteract the high serotonergic output, producing uncoupling between serotonin level and behavioural state. The results support the notion that γ-aminobutyric acid is a strong modulator of dorsal raphe nucleus serotonergic neurons, and that this modulation is important in the regulation of slow wave sleep, rapid eye movement sleep and waking. [Copyright &y& Elsevier]

Depression in humans is associated with sleep abnormalities of three types: altered rapid eye movement (REM) sleep, fragmented sleep, and reduced delta sleep. In an animal model of depression, chronic exposure to mild stressors (CMS, e.g. periods of soiled cage, reversed light/dark cycle, grouped housing, food and/or water deprivation) causes behavioral and hormonal changes which, in humans, often are associated with depression. In the CMS model, a reduced sucrose intake has been defined as one of the core symptoms of depression, anhedonia, although this finding is not consistent among various laboratories. In the present study, we investigated if the CMS procedure, in our laboratory, would cause decreased sucrose intake and, also, give sleep changes similar to what is found in depressed patients.Exposure to CMS decreased sucrose intake in our rats. The largest effect was obtained after 2 weeks of the stress protocol. CMS rats spent more time in REM sleep and showed more fragmented sleep compared to their baseline recording, while there were no changes in the control rats. Increased sleep fragmentation in CMS rats was particularly evident by increased number of arousals, and increased REM sleep and slow-wave-sleep-1 (SWS-1) episodes. The duration of sleep stage episodes was decreased. The amount of slow-wave-sleep-2 (SWS-2) was not decreased, however SWS-2 in percent of total SWS was reduced. Correlation analysis showed that animals that had less consumption of sucrose spent more time in REM sleep and had increased number of REM sleep episodes. In this study, CMS appears to be a model of depression. [Copyright &y& Elsevier]

Childhood sexual abuse (CSA) is associated with sleep disturbances in adulthood. However, longitudinal studies have yet to identify among CSA-survivors subgroups distinguished by the trajectory of their insomnia severity, or predictors of subgroup membership. The objective of this study was to examine longitudinal insomnia symptom trajectories, as well as predictors and correlates of the identified trajectories, over a 4 year study period in a sample of adult, mainly female CSA-survivors. The sample comprised 533 adult survivors of CSA (94.9% women, mean age 39.2 years, mean age of abuse onset 6.5 years), recruited from support centers for sexual abuse survivors in Norway. Latent class growth analyses were used to identify insomnia symptom trajectories. Three distinct trajectories of insomnia symptoms were identified; one characterized by high insomnia symptom scores minimally decreasing over the study period (' high and decreasing ', 30.6%), one characterized by stable intermediate insomnia symptom scores (' intermediate and stable ', 41.5%), and one characterized by stable low insomnia symptom scores (' low and stable ', 27.9%). Predictors of belonging to the high and decreasing trajectory (using the low and stable trajectory as a reference), was lower age of abuse onset (expotentiated coefficient (EC): 0.93, p = 0.026), abuse involving penetration (EC: 2.36, p = 0.005), threats (EC: 3.06, p < 0.001) or physical violence (EC: 3.29 p < 0.001), a higher score on a composite variable comprising multiple other abuse and perpetrator aspects (EC: 2.55, p < 0.001), as well as scoring above a clinical cut-off on a measure of posttraumatic stress symptoms (EC: 12.17, p < 0.001). Those belonging to the high and decreasing trajectory also reported lower levels of perceived social support and higher levels of subjectively experienced relational difficulties compared to those belonging to the two other trajectories. We conclude that different longitudinal insomnia trajectories exist among adult CSA survivors. The overall results, as well as the significant predictors, are discussed alongside their potential clinical implications. [ABSTRACT FROM AUTHOR]

Objective: Delayed Sleep-Wake Phase Disorder (DSWPD) is associated with negative outcomes, including reduced daytime performance and difficulties with treatment adherence. These outcomes are mediated by executive functions (EF). In this study, we investigated whether patients with DSWPD report inferior EF compared to a control group. The study consisted of 40 patients diagnosed with DSWPD (12 males, mean age 20.7 (±3.1)) and 20 healthy controls (six males, 21.3 (±2.2), p = 1.00) between 16 and 25 years (p = 0.42).Methods: Behavior Rating Inventory of Executive Function-Adult version Self-Report (BRIEF-A) was used for adults ≥18 years (DSWPD n = 28; controls n = 17) whereas Behavior Rating Inventory of Executive Function Self-Report Version (BRIEF-SR) was used for assessment of EF in adolescents <18 years (DSWPD n = 12; controls n = 3). Independent samples t-tests were used to compare patients to controls.Results: The total group of patients with DSWPD scored significantly poorer compared to the control group on the main indexes; Behavioral Regulation Index (BRI) (p = <0.0005), Metacognition Index (MI) (p = <0.0005), and Global Executive Composite (GEC) (p = <0.0005). The adult group with DSWPD scored significantly poorer than the adult control group on eleven of the twelve BRIEF-A scales. Among patients <18 years, the DSWPD-group scored significantly poorer than the control group on 8 of the 13 BRIEF-SR-scales.Conclusion: Patients with DSWPD reported significantly poorer EF compared to controls. Assessment of EF in patients with DSWPD can be valuable for understanding the consequences of the disorder regarding treatment tailoring and adherence. [ABSTRACT FROM AUTHOR]

Study Objectives: Difficult early morning awakening is a primary symptom of delayed sleep-wake phase disorder (DSWPD), however, it remains poorly investigated. Our main objective was to quantify the awakening threshold in DSWPD-patients and healthy controls as well as investigate a possible relationship with sleep stages. A secondary objective was to compare habitual sleep measured by polysomnography and actigraphy between patients and controls.Methods: Twenty DSWPD patients and 16 controls had two polysomnographic recordings at a sleep laboratory. Participants followed their habitual sleep-wake schedule on the first night and a forced sleep-wake schedule (00:00-07:00 h) on the second night. We used a custom-made alarm clock was for the forced-night awakening, starting at 72 dB sound intensity which increased up to 104 dB.Results: Mean awakening threshold in dB was higher in patients compared to controls; 75.5 vs. 72.6, p = 0.01, and the difference could not be explained statistically by sleep-time. Patients who were in REM sleep upon attempted awakening had a higher awakening threshold compared to patients who were in NREM sleep; 80.0 vs 74.7, F = 6.4, p = 0.02. Patients had increased sleep onset latency both at home with actigraphy and by PSG during the first laboratory night (20.6 vs 12.1 min, p = 0.004), however no further differences between the groups were observed regarding sleep structure.Conclusions: A high early-morning forced awakening threshold in DSWPD was related to REM sleep. Sleep onset problems, even with habitual bedtimes, may also be an integral feature of DSWPD. [ABSTRACT FROM AUTHOR]

In the present study, our aim was to examine longitudinal posttraumatic stress symptom (PTSS) trajectories in a Norwegian sample of adults who had experienced sexual abuse during childhood, and to identify predictors of PTSS-trajectory belongingness. The sample consisted of 138 adult survivors of childhood sexual abuse (96.4% women, mean age = 42.9 years, mean age at the first abuse = 5.9 years), recruited from support centers for sexual abuse survivors. The majority (78.3%) reported penetrative abuse, and a large proportion of the sample reported that the perpetrator was a biological parent (38.4%) or someone they trusted (76.1%), reflecting a high severity level of the abusive experiences. Latent Profile Analyses revealed the best overall fit for a two PTSS-trajectories model; one trajectory characterized by sub-clinical and decreasing level of PTSS (54.9%), and the other by high and slightly decreasing level of PTSS (45.1%). Increased odds for belonging to the trajectory with clinical level symptoms was found among those who reported higher levels of exposure to other types of childhood maltreatment (OR = 3.69, p = 0.002), sexual abuse enforced by physical violence (OR = 3.04, p = 0.003) or threats (OR = 2.56, p = 0.014), very painful sexual abuse (OR = 2.73, p = 0.007), or who had experienced intense anxiety, helplessness or fear during the abuse (OR = 2.97, p = 0.044). Those in the trajectory with clinical level PTSS reported lower levels of perceived social support and more relational difficulties compared to those in the sub-clinical PTSS trajectory. In conclusion, different longitudinal PTSS trajectories can be found among adult survivors of childhood sexual abuse. Significant predictors of PTSS-trajectory belongingness are discussed alongside their potential implications for preventive efforts and clinical interventions. [ABSTRACT FROM AUTHOR]

In the present study, we examined the role of cumulative childhood maltreatment experiences for several health related outcomes in adulthood, including symptoms of psychological distress as well as perceived social support and hardiness. The sample comprised adult survivors of sexual abuse (N = 278, 95.3% women, mean age at first abusive incident = 6.4 years). One-way ANOVAs revealed a statistically significant dose-response relation between cumulative childhood maltreatment scores and self-reported symptoms of posttraumatic stress (PTSS), anxiety, depression, eating disorders, dissociation, insomnia, nightmare related distress, physical pain, emotional pain, relational problems, self-harm behaviors as well as on a measure of symptom complexity. Cumulative childhood maltreatment was also associated with lower levels of work functioning. An inverse dose-response relation was found for perceived social support and hardiness. Using a Bonferroni corrected alpha level, cumulative childhood maltreatment remained significantly associated with all outcome measures with the exception of eating disorder symptoms after controlling for abuse-related independent variables in hierarchical regression analyses. Results add to previous literature by showing that dose-response relation between cumulative childhood adversities and adult symptom outcomes could also be identified in a sample characterized by high exposure to adversities, and lends support to the notion put forth by previous authors that cumulative childhood adversities seem to be related to the severity of adult health outcomes in a rule-governed way. [ABSTRACT FROM AUTHOR]

Summary: Objective: The stress hormone cortisol shows a pronounced endogenous diurnal rhythm, which is affected by the sleep/wake cycle, meals and activity. Shift work and especially night work disrupts the sleep/wake cycle and causes a desynchronization of the natural biological rhythms. Therefore, different shift schedules may have different impact on performance at work and health. Aim: The purpose was to study if health, reaction time, and the cortisol rhythm were negatively affected when a group of shift workers changed their work schedule from ordinary day–night shift (fixed shift) to “swing shift”. Methods and settings: 19 healthy workers on a Norwegian oil rig participated in the study. They worked 2 weeks offshore followed by 4 weeks off work. The ordinary schedule consisted of 12-h day shift and 12-h night shift every other work period (14 days or nights=fixed shift). “Swing shift” involved 1 week of night shift, followed by 1 week of day shift during the work period. All participants worked ordinary day–night shift when baseline data were collected (questionnaires, saliva cortisol, and reaction time during work). After collection of baseline data the workers changed their work schedule to “swing shift”, for every working period, and 9 months later the same data were collected. Results: “Swing shift” did not give any negative health effects or any negative changes in reaction time during the day they shifted from night work to day work. Personnel adapted to night shift within a week regardless of schedule, but recovery from night shift took longer time. During swing shift the cortisol rhythm went back towards a normal rhythm in the second week, but it was not returned completely to normal values when they returned home for the 4 weeks off period. However, the cortisol rhythms were readapted to normal values after 1 week at home. For personnel returning home directly from 14 consecutive night shifts, cortisol adaptation was not complete after 1 week at home. Conclusion: We found no increase in health complaints from swing shift or reaction time in the shift from night to day work. Recovery from night shift takes longer time. [Copyright &y& Elsevier]

Abstract: The paper presents data from a randomized controlled trial comparing treatment effects of cognitive behavioural therapy (CBT), hypnotic treatment (Zopiclone), and placebo in a sample of insomnia patients. Data from the same trial have already demonstrated that CBT was more efficient in improving sleep than Zopiclone. The novel outcomes that are reported here concern daytime functioning. Forty-six older patients (age⩾55) qualifying for a diagnosis of primary insomnia were recruited to participate. Assessments were completed at baseline, post-treatment, and at a 6-months follow-up, and measures of worry, anxiety, depression, interpersonal relationships, subjective alertness, vigilance, and quality of life were used. The participants in both treatment conditions scored within the normal range on the outcome measures at baseline with the exception of reporting less alertness, relative to a group of good sleepers. One interaction effect indicated that subjective alertness improved more in the Zopiclone group than the CBT group from baseline to post-treatment, and another that CBT was more effective than Zopiclone in reducing trait anxiety from baseline to follow-up. It was concluded that the treatments yielded only minor effects on the measures of daytime functioning, and that none of them was clearly superior to the other. [Copyright &y& Elsevier]

Abstract: Background: The purpose of this study was to assess how seasonal changes in mood and behaviour were associated with depression and anxiety symptoms in a sample from a general population, and to investigate how prevalence figures were affected by month of questionnaire completion. Methods: The target population included all individuals in the Hordaland county (Norway) born 1953–57 (N =29,400). In total, 8598 men (57% response rate) and 9983 women (70% response rate) attended the screening station. Half of the men (randomly chosen) and all of the women were offered a questionnaire to fill in with items on seasonality. This was measured using the Global Seasonality Score (GSS), a central component of the Seasonal Pattern Assessment Questionnaire (SPAQ). The Hospital Anxiety and Depression Scale (HADS) was used to measure anxiety and depression. Both questionnaires were completed by 2980 men (68.9%) and 8074 women (80.9%). Results: Seasonality was positively associated with levels of both anxiety and depression regardless of the season the interview took place. In subjects with a low/moderate degree of seasonality there were modestly higher levels of depressive symptoms during November through March than the other months. Limitations: We had a substantial number of non-responders. Conclusions: Our results raise the possibility of seasonality being a separate dimensional trait associated with both anxiety and depression. [Copyright &y& Elsevier]

Abstract: One of the most established hypotheses of depression focuses on alteration of the serotonergic (5-HT) function. Recent evidence suggests that serotonergic involvement in depression may be modulated by the action of gamma-hydroxybutyric acid (GABA). Furthermore, altered GABAergic function is also evident in depressed patients and in animal models of depression. Disturbed sleep is characteristic of patients with mood disorders. The most pronounced changes of the 5-HT firing activity occur during sleep. Hence, the present paper reports a study on simultaneously measurement of hippocampal levels of serotonin and GABA during waking and sleep in the chronic mild stress (CMS) animal model of depression. The neurotransmitter findings are accompanied by depression-like symptoms (e.g. sleep alterations and reduced sucrose intake, a putative indicator of anhedonia in rodents). Our results show that animals exposed to CMS had lower hippocampal GABA levels compared to controls. In addition, after CMS there was a lack of 5-HT stage-dependency. A subgroup (five out of eight animals) showed a consistent increase in 5-HT levels in slow wave sleep and REM sleep. We also observed that this increase occurred in those animals regarded as most anhedonic (lowest intake of sucrose solution). Moreover, REM sleep was positively correlated with anhedonia. No interaction between 5-HT and GABA was found in the hippocampus. The data suggest that both GABAergic and serotonergic systems may be simultaneously but independently involved in depression. The alteration in 5-HT function may represent a link between depression-like behaviour and sleep abnormalities found in depressed patients. [Copyright &y& Elsevier]

Abstract: Chronic stress is linked to development of depression and may trigger neurobiological changes underlying the disease. Downregulation of the secretory peptide brain-derived neurotrophic factor (BDNF) and the transcriptional regulator calcium/cyclic-AMP responsive binding protein (CREB) have been implicated in stress and depression-related pathology in animal studies. When animals are exposed to the chronic mild stress (CMS) protocol, multiple depression-like symptoms are observed. Here we investigated the effect of CMS on BDNF protein expression and CREB activation in the dentate gyrus and hippocampus proper. Rats exposed for 5 weeks to repeated, unpredictable, mild stressors showed reduced BDNF expression and inhibited phosphorylation of CREB (Ser-133) in the dentate gyrus (−25.0%±3.5% and −29.7±7.3%, respectively), whereas no significant effects were observed in the hippocampus proper. CMS-treated rats consumed less sucrose compared to control rats, indicating a state of anhedonia. Moreover, phospho-CREB levels in the dentate gyrus were positively correlated with the animals'' sucrose intake at the end of the CMS protocol. These results couple chronic mild stress to a downregulation of CREB activity and BDNF protein expression specifically within the dentate gyrus and support the possibility that the BDNF-CREB system plays an important role in the response to environmental challenges. [Copyright &y& Elsevier]

Abstract: Many symptoms of human depressive disorders are also observed in animals after exposure to unpredictable stressors. The chronic mild stress (CMS) paradigm was developed in order to better model the human situation by using chronic mild stressors over a longer period. It is claimed that the model induces anhedonia in the animals, a core symptom of depression in humans. Despite the fact that the CMS model has a high degree of face validity, there are a number of laboratories in which the establishment of the model is less reliably observed. We have examined behavior (sexual activity and open field activity) together with hedonic measures (sucrose and saccharine intake) after exposure to CMS. CMS decreased male sexual activity (e.g. reduced capability to ejaculate) and increased activity in an open field test. The hedonic measures showed diverging results after CMS in our laboratory. Sucrose consumption was reduced, while saccharine consumption did not show a comparable change. It is concluded that CMS induces comparable alterations to some depression-like symptoms in humans. Saccharine consumption is not a reliable indicator of the hedonic responsiveness to CMS. [Copyright &y& Elsevier]

Cross-sectional studies have consistently reported an inverse association between perceived social support and the severity of mental health symptoms among adult survivors of childhood sexual abuse (CSA). However, there is a lack of longitudinal studies investigating the bidirectional association between social support and the severity of symptoms among adult CSA-survivors, as well as the role of relational problems in predicting perceived social support and symptom levels over time. The present study addressed these questions in a sample of primarily female CSA-survivors. In a three-wave, four-year longitudinal study of 506 CSA-survivors (94.9% women, 5.1% men) recruited from support centers for sexual abuse survivors in Norway, we used cross-lagged panel structural equation modeling to examine the directionality of the longitudinal associations between perceived social support and symptoms of posttraumatic stress, anxiety, depression and insomnia. Cross-lagged panel analyses revealed significant weak reciprocal associations between perceived social support and depression, posttraumatic stress symptoms and anxiety symptoms, but not with insomnia symptoms. The observed effects were partly overlapping and partly inconsistent across the different symptom domains. Relational problems predicted social support cross-sectionally and longitudinally, whereas only cross-sectional associations were found between the relational problems variable and mental health symptoms. Theoretical and clinical implications of the findings are discussed, alongside methodological limitations of the study. [ABSTRACT FROM AUTHOR]