Circadian Rhythm

Objective: The authors summarize current knowledge regarding the psychomotor symptoms of depression. Method: Findings from the objective quantification of psychomotor symptoms are reviewed, and methodological issues are considered. The contemporary empirical literature regarding the diagnostic, prognostic, and potential pathophysiologic significance of psychomotor symptoms is summarized. Results: It has been repeatedly shown that depressed patients differ from normal and psychiatric comparison groups with regard to objectively quantified gross motor activity, body movements, speech, and motor reaction time. Course of illness, diurnal variation, medication status, sex, and age are associated with agitation and retardation and should be controlled when one is studying psychomotor symptoms. Psychomotor symptoms in depression may have unique significance. They have high discriminative validity, may be the only symptoms of depression that distinguish depression subtypes, and are predictive of good response to tricyclic antidepressants. Results of brain imaging and biochemical studies link depression and motor symptoms to abnormalities in the basal ganglia and basal ganglia/thalamo-cortical circuits. Conclusions: The investigation of psychomotor disturbance in depression is specifically consistent with neo-Kraepelinian standards for the study of psychiatric disorders. Our current knowledge of psychomotor symptoms is conceptually obscure, yet a large body of evidence specifies their manifestation and supports their significance. Identifying the incidence of abnormal motor behaviors in depressed patients and assessing the component processes that accompany and determine their manifestation may be important advances in the study of psychomotor symptoms in depression. (Am J Psychiatry 1997; 154:4-17)

Acute stress is a fundamental adaptive response which enables an organism to cope with daily threatening environmental stimuli. If prolonged and uncontrollable, the stress response may become inadequate and ultimately result in health damage. Animal models of stress in rodents indicate that both acute and chronic stressors have pronounced effects on sleep architecture and circadian rhythms. One major physiological response elicited by stress is activation of the hypothalamo-pituitary-adrenal axis. In both animals and humans, the hypothalamo-pituitary-adrenal axis plays an important role in sleep-wake regulation and in alterations of the sleep-wake cycle secondary to exposure to acute or chronic stressors. In humans, dysfunction of the neuroendocrine regulation of sleep can lead to severe sleep disturbances. The progressive decay of the hypothalamo-pituitary-adrenal axis in elderly people, which mimics chronic exposure to stress, may contribute to fragmented and unstable sleep in ageing. Shift workers, chronic insomniacs or patients suffering from mental disorders show abnormal hypothalamo-pituitary-adrenal secretory activity and concomitant sleep disturbances. Those sleep disorders and possible underlying mechanisms are briefly reviewed.

Acute stress is a fundamental adaptive response which enables an organism to cope with daily threatening environmental stimuli. If prolonged and uncontrollable, the stress response may become inadequate and ultimately result in health damage. Animal models of stress in rodents indicate that both acute and chronic stressors have pronounced effects on sleep architecture and circadian rhythms. One major physiological response elicited by stress is activation of the hypothalamo-pituitary-adrenal axis. In both animals and humans, the hypothalamo-pituitary-adrenal axis plays an important role in sleep–wake regulation and in alterations of the sleep–wake cycle secondary to exposure to acute or chronic stressors. In humans, dysfunction of the neuroendocrine regulation of sleep can lead to severe sleep disturbances. The progressive decay of the hypothalamo-pituitary-adrenal axis in elderly people, which mimics chronic exposure to stress, may contribute to fragmented and unstable sleep in age...

Chtourou, H and Souissi, N. The effect of training at a specific time of day: A review. J Strength Cond Res 26 : 2012-This article focuses on physical performances after training at a specific time of day. To date, although the effect of time of day on aerobic performances appears to be equivocal, during anaerobic exercises, the effect of time of day has been well established with early morning nadirs and peak performances in the late afternoon. These diurnal rhythms can be influenced by several factors such as the regular training at a specific time of day. Indeed, regular training in the morning hours may increase the lower morning performances to the same or even higher level as their normal diurnal peak typically observed in the late afternoon by a greater increase of performance in the evening. However, regular training in the evening hours may increase the morning-evening (i.e., amplitude of the rhythm) difference by a greater increase of performance in the late afternoon. Therefore, adaptations to training are greater at the time of day at which training is regularly performed than at other times. Nevertheless, although modifications in resting hormones concentrations could explain this time-of-day specific adaptations, precise information on the underlying mechanisms is lacking. . Circadian rhythm in core temperature, peak (P peak ) and mean (P mean ) powers during the Wingate test, and maximal power (P max ) during the forcevelocity test. Drawn from data presented by Souissi et al. (110).

Background: Previous studies suggest circadian rhythm disturbances in children with attention-deficit/hyperactivity disorder (ADHD) and sleep-onset insomnia (SOI). We investigate here sleep and rhythms in activity and melatonin in adults with ADHD.

Assessment of sympathoadrenal medullary system (SAM) activity is only possible to date via measurement of catecholamines in blood plasma or via electrophysiological methods. Both ways of measurement are restricted to endocrinological or psychophysiological laboratories, as both require either immediate freezing of blood samples or complex recording devices. Efforts have therefore been undertaken to find a method comparable to salivary cortisol measurements, in which noninvasive samples can be taken at any place and stored at room temperature for sufficient time before later analysis in the laboratory. Salivary alpha-amylase (sAA) is a candidate that may prove useful in this context. We show here that sAA activity is increased by acute psychosocial stress (Trier Social Stress Test) and that increases in sAA correlate with increases in norepinephrine. We further report that sAA exhibits a stable circadian pattern that mirrors that of salivary cortisol. In conclusion, the current data show that salivary alpha-amylase may serve as an easy-to-use index for SAM activity. However, some questions remain to be answered; for example, what impact does salivary flow rate exert on stress-induced sAA activity?

Attention-deficit/hyperactivity disorder (ADHD) and bipolar disorder (BD) are neurodevelopmental disorders with onset in childhood and early adolescence, and common persistence in adulthood. Both disorders are often undiagnosed, misdiagnosed, and sometimes over diagnosed, leading to high rates of morbidity and disability. The differentiation of these conditions is based on their clinical features, comorbidity, psychiatric family history course of illness, and response to treatment. We review recent relevant findings and highlight epidemiological, clinical, family history, course, and treatment-response differences that can aid the differential diagnosis of these conditions in an outpatient pediatric setting.

The biological clock, the suprachiasmatic nucleus (SCN), is essential for our daily well-being. It prepares us for the upcoming period of activity by an anticipatory rise in heart rate, glucose and cortisol. At the same time the 'hormone of the darkness', melatonin, decreases. Thus, the time-ofday message penetrates into all tissues, interestingly not only by means of hormones but also by a direct neuronal influence of the SCN on the organs of the body. The axis between the SCN and the paraventricular nucleus of the hypothalamus (PVN) is crucial for the organization/ synchronization of the neuroendocrine and autonomic nervous system with the time of day. This SCNneuroendocrine PVN axis takes care of a timely hormonal

The social zeitgeber theory . Social zeitgebers and biological rhythms. Archives of General Psychiatry, 45, 948-952] offers an explanation of how life events trigger depressive episodes. According to this theory, life stress leads to mood episodes by causing disruptions in individuals' social routines and, in turn, their biological circadian rhythms. In this article, we review the literature pertaining to the social zeitgeber theory, as well as evidence that this theory may be applied to (hypo)manic episodes. Given the limited data supporting the social zeitgeber theory to date, we also evaluate whether circadian rhythm disruptions are triggered by an internal mechanism, such as an abnormality in one's pacemaker (the suprachiasmatic nucleus; SCN). We review these two theories in an attempt to understand the potential causes of circadian rhythm disruptions and affective episodes in individuals with unipolar and bipolar disorders. We also propose several areas of future research.

It has been suggested that sleep may have a positive effect on morning motor symptoms in Parkinson's disease (PD). We examined this possibility and also looked at common sleep disorders in PD. Seventy-eight PD patients and 43 normal elderly subjects answered a questionnaire. Of the PD patients, 43.6% reported improved motor symptoms in the morning, 37.2% worse, and 19.2% unchanged compared to the rest of the day. No difference was found between morning-better and -worse groups with respect to age, duration or stage of PD; antiparkinsonian medications utilized, and predominant motor symptoms. However, the morning-same group had a shorter duration of PD and less severe disease and required fewer dopaminergic medications. Sleep disorders were seen with equal frequency in the morning-better and -worse groups. Our results suggest that sleep does not have a direct effect on morning motor function. Alterations in morning motor symptomatology probably represent a manifestation of motor fluctuations. Sleep fragmentation and spontaneous daytime dozing occurred much more frequently in PD patients than controls. In addition, nocturnal vocalizations and daytime hallucinations occurred only in the PD group.

Exercise is integral to the life of T1DM subjects. Several factors influence the metabolic response to exercise in these patients. Despite physical and psychological benefits of exercise, its hypo- and hyperglycemic effects may cause discouragement from participation in sports and games. To use existing evidence from literature to provide practical indications for the management of insulin therapy in subjects with T1DM who practice sports or physical activities. Bibliographic research was performed on PubMed and the main Systematic Review and Guidelines database were also searched. Existing guidelines are useful but the exact adjustments of insulin dose must be made on an individual basis and these adjustments can be made only by "trial and error" approach. These clinical indications may be a starting point from which health care providers can find practical advices for each patient.

Objective: To investigate the effect of melatonin treatment on sleep, behavior, cognition, and quality of life in children with attention-deficit/hyperactivity disorder (ADHD) and chronic sleep onset insomnia. Method: A total of 105 medication-free children, ages 6 to 12 years, with rigorously diagnosed ADHD and chronic sleep onset insomnia participated in a randomized, double-blind, placebo-controlled trial using 3 or 6 mg melatonin (depending on body weight), or placebo for 4 weeks. Primary outcome parameters were actigraphy-derived sleep onset, total time asleep, and salivary dim light melatonin onset. Results: Sleep onset advanced by 26.9 T 47.8 minutes with melatonin and delayed by 10.5 T 37.4 minutes with placebo (p < .0001). There was an advance in dim light melatonin onset of 44.4 T 67.9 minutes in melatonin and a delay of 12.8 T 60.0 minutes in placebo (p < .0001). Total time asleep increased with melatonin (19.8 T 61.9 minutes) as compared to placebo (j13.6 T 50.6 minutes; p = .01). There was no significant effect on behavior, cognition, and quality of life, and significant adverse events did not occur. Conclusion: Melatonin advanced circadian rhythms of sleep-wake and endogenous melatonin and enhanced total time asleep in children with ADHD and chronic sleep onset insomnia; however, no effect was found on problem behavior, cognitive performance, or quality of life. J. Am. Acad. Child Adolesc.

There is evidence showing that HPA axis responses to pharmacological provocation depend on time of day with larger cortisol responses in the afternoon and evening compared to the morning hours. However, it is still unknown whether HPA axis responses to psychological stress are affected by time of day and whether they can be assessed with equal reliability in the morning and afternoon, respectively. The present reanalysis is based on five independent studies conducted in the same laboratory by and. All subjects were confronted with the Trier Social Stress Test (TSST) either in the morning or in the afternoon. The total sample consisted of 180 adults with 115 younger (49 females, 66 males) and 65 older adults (32 females, 33 males). All ANCOVA results controlled for possible age and gender effects. Stress-related free salivary cortisol, total plasma cortisol and ACTH net increases did not differ according to time of day (all p = n.s.). However, as expected pre-stress free salivary and total plasma cortisol levels differed significantly between the morning and afternoon group (both p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.005), leading to a significantly higher free cortisol area under the curve (AUC) in the morning (p = 0.02). Taken together, these observations suggest that the adrenal glands may be more sensitive to ACTH in the morning. Additionally, higher basal salivary cortisol levels were related to a lower stress-related net increase in salivary cortisol (p = 0.02), total plasma cortisol (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001), and marginally ACTH (p = 0.09). Stress-related heart rate increases did not differ between groups (p = n.s.). The finding that the TSST-induced mood change was differentially affected by time of day requires further exploration. We conclude that comparable HPA axis and heart rate stress responses to psychosocial stress can be measured in the morning and afternoon.

Background: The study aimed to elucidate previously observed associations between morningness-eveningness and depressive symptomatology in university students. Relations between components of depressive symptomatology and morningness-eveningness were analysed.
Methods: Nine hundred and seventy-four university students completed Polish versions of the Centre for Epidemiological Studies – Depression scale (CES-D; Polish translation appended to this paper) and the Composite Scale of Morningness. Principal component analysis (PCA) was used to test the structure of depressive symptoms. Pearson and partial correlations (with age and sex controlled), along with regression analyses with morning affect (MA) and circadian preference as predictors, were used.
Results: PCA revealed three components of depressive symptoms: depressed/somatic affect, positive affect, interpersonal relations. Greater MA was related to less depressive symptoms in three components. Morning circadian preference was related to less depressive symptoms in depressed/somatic and positive affects and unrelated to interpersonal relations. Both morningness-eveningness components exhibited stronger links with depressed/somatic and positive affects than with interpersonal relations. Three CES-D components exhibited stronger links with MA than with circadian preference. In regression analyses only MA was statistically significant for positive affect and better interpersonal relations, whereas more depressed/somatic affect was predicted by lower MA and morning circadian preference (relationship reversed compared to correlations).
Limitations: Self-report assessment.
Conclusions: There are three groups of depressive symptoms in Polish university students. Associations of MA with depressed/somatic and positive affects are primarily responsible for the observed links between morningness-eveningness and depressive symptoms in university students. People with evening circadian preference whose MA is not lowered have less depressed/somatic affect.

Sleep inertia is a transitional state of lowered arousal occurring immediately after awakening from sleep and producing a temporary decrement in subsequent performance. Many factors are involved in the characteristics of sleep inertia. The duration of prior sleep can influence the severity of subsequent sleep inertia. Although most studies have focused on sleep inertia after short naps, its effects can be shown after a normal 8-h sleep period. One of the most critical factors is the sleep stage prior to awakening. Abrupt awakening during a slow wave sleep (SWS) episode produces more sleep inertia than awakening in stage 1 or 2, REM sleep being intermediate. Therefore, prior sleep deprivation usually enhances sleep inertia since it increases SWS. There is no direct evidence that sleep inertia exhibits a circadian rhythm. However, it seems that sleep inertia is more intense when awakening occurs near the trough of the core body temperature as compared to its circadian peak. A more controversial issue concerns the time course of sleep inertia. Depending on the studies, it can last from 1 min to 4 h. However, in the absence of major sleep deprivation, the duration of sleep inertia rarely exceeds 30 min. But all these results should be analysed as a function of type of task and dependent variables. Different cognitive functions are probably not sensitive to the same degree to sleep inertia and special attention should be provided to dependent variables as a result of the cognitive processes under review. Finally, sleep disorders represent risk factors which deserve new insight in treatment strategies to counteract the adverse effects of sleep inertia.

Background: Diurnal variation in mood is a prominent symptom of depression, and is typically experienced as positive mood variation (PMVmood being worse upon waking and better in the evening). The present study sought to advance understanding of PMV by measuring daily mood variation in non-clinical individuals with varying levels of depressed mood. Based on research into normative variation in mood and evidence that circadian amplitudes may be decreased in depression, it was hypothesised that compared to those with low levels of depression, individuals meeting Centre for Epidemiological Studies-Depression Scale (CES-D) cut-off for probable depression would exhibit an attenuated circadian component in diurnal variation of Positive Affect (PA). Method: Ninety-nine young healthy women (mean age = 21.5, SD = 3.0) living on a normal sleep-wake schedule provided mood reports every two hours between 0800 h and 2200 h for 7 days. Results: The high depression group (CES-D ≥ 23, n = 22) exhibited a pattern of diurnal variation consistent with PMV (increased PA in the evening relative to the morning). As predicted, evidence was also found that the high depression group was characterized by a decreased circadian component to diurnal variation in PA relative to the low depression group (CES-D b 23, n = 77). Conclusions: It is provisionally concluded that diurnal mood variation in depression can usefully be understood from the perspective of weakened circadian function. Findings are discussed in terms of limitations of the study's naturalistic design and future research avenues identified.

Sleep spindles are a distinctive EEG phasic feature of NREM sleep and are prevalent during stage 2 as compared to slow wave sleep. While the neurophysiological mechanisms of spindle generation, that involves thalamic and corticothalamic networks, have been recently delineated and are brie¯y reviewed, their de®nitive functional meaning still remains to be elucidated. This review summarizes the present knowledge on visually scored and automatically detected spindles, as well as the literature on EEG power in the sigma band. Among the factors known to affect sleep spindles and sigma activity, their intra-cycle temporal dynamics, their time-course across sleep cycles, the reciprocal relationship with delta activity, the effects of sleep deprivation, of circadian factors and of ageing, and their role in information processing have been discussed. Moreover, speci®c attention has been paid to the existence of functionally and topographically distinct slow-and fastspindles, also taking into account the presence of large inter-individual differences. Nevertheless, several fundamental issues remain to be elucidated: the physiological mechanisms controlling age-related changes in spindle parameters; the role of melatonin as a spindle-promoting agent; the relationships between plastic mechanisms (after stroke, or as a consequence of learning) and modi®cations in spindle activity; the possibility of using some spindle parameters as an index of the severity of developmental disorders in abnormal maturational processes. &

The present study investigates whether the circadian preferences of students are related to their academic achievements. This study explores whether different class times affect students' achievement and examines the performance of students on final exams administered at 09:30 h for differences according to chronotype. A total of 1471 university students between 18 and 25 yrs of age responded to a morningness-eveningness questionnaire (MEQ), and data on their cumulative grade point averages (CGPA) were also collected from their transcripts. Some of the students in the sample attended classes during the first teaching period, which started at 08:00 h and ended at 14:50 h, and the remaining students followed the second schedule, which started at 15:00 h and ended at 21:50 h. MEQ scores were found to differ by sex. MEQ scores partially predicted academic success and that students' academic achievements differed according to the time of the teaching period. Moreover, final exam (administered at 09:30 h) scores differed with respect to their circadian preferences; students with a morning preference achieved higher scores than either those with an evening or intermediate preference. Both teaching and test start times thus impact academic performance.

Background: There are many health and social benefits of physical activity (PA) for older adults, but little is known about their activity patterns. Purpose: The purpose of this study was to objectively assess the PA patterns of older adults and the lifestyle and demographic factors associated with PA. Methods: Participants (N = 230, aged 78.1 yr) recruited from medical practices (between 2007 and 2008) completed journey logs and wore accelerometers for 7 d. Mean daily steps, counts per minute (CPM), minutes of sedentary, light, or moderateto-vigorous PA (MVPA), and frequency of journeys were analyzed (in 2009). Results: Younger participants (age = 70-74.9 yr) were significantly (P G 0.001) more active (5660.8 steps per day) than older participants aged 80+ yr (3409.6 steps per day). Men performed significantly (P = 0.035) more minutes MVPA than women (23.1 vs 13.8 min MVPA per day). Normal weight participants were significantly (P G 0.05) more active (5368.9 steps per day) than overweight (4532.7 steps per day) and obese (3251.4 steps per day) groups. Those performing many journeys (911.6 journeys per week) were significantly (P G 0.001) more active (5838.2 steps per day) than those performing few (G7 journeys per week) (3094.2 steps per day). PA was significantly (P G 0.001) greater in mornings (259.3 CPM) than afternoons (181.8 CPM) and evenings (102.5 CPM). Sundays were significantly (P G 0.001) less active (3331.7 steps per day) than Saturdays (4193.1 steps per day) and weekdays (4623.5 steps per day). Light activity was significantly (P = 0.005) higher in spring (3.4 hId j1 ) than that in winter (2.7 hId j1 ). Conclusions: Older adults' PA patterns differ by age, gender, and weight status. Daily journeys are associated with more activity for all groups. Variability in volume of activity is high for all age groups. Temporal patterns of PA indicate that journeys out of the house for shopping and personal business are important in their contribution to PA levels.

Overwhelming evidence supports the importance of sleep for memory consolidation. Medical students are often deprived of sufficient sleep due to large amounts of clinical duties and university load, we therefore investigated how study and sleep habits influence university performance. We performed a questionnaire-based study with 31 medical students of the University of Munich (second and third clinical semesters; surgery and internal medicine). The students kept a diary (in 30-min bins) on their daily schedules (times when they studied by themselves, attended classes, slept, worked on their thesis, or worked to earn money). The project design involved three 2-wk periods (A: during the semester; B: directly before the exam period-pre-exam; C: during the subsequent semester break). Besides the diaries, students completed once questionnaires about their sleep quality (Pittsburgh Sleep Quality Index [PSQI]), their chronotype (Munich Chronotype Questionnaire [MCTQ]), and their academic history (previous grades, including the previously achieved preclinical board exam [PBE]). Analysis revealed significant correlations between the actual sleep behavior during the semester (MS diary ; mid-sleep point averaged from the sleep diaries) during the pre-exam period and the achieved grade (p ¼ 0.002) as well as between the grades of the currently taken exam and the PBE (p ¼ 0.002). A regression analysis with MS diary pre-exam and PBE as predictors in a model explained 42.7% of the variance of the exam grade (effect size 0.745). Interestingly, MS diary -especially during the pre-exam period-was the strongest predictor for the currently achieved grade, along with the preclinical board exam as a covariate, whereas the chronotype did not significantly influence the exam grade.

Objective: Previous data from our group and others have shown that salivary alphaamylase activity increases in response to stress. It has been suggested that salivary alphaamylase may be a marker for adrenergic activity. Less is known about other determinants of salivary alpha-amylase activation. The objective of the current study was to describe the diurnal pattern of salivary amylase and its determinants. Methods: Saliva samples were collected immediately after waking-up, 30 and 60 min later, and each full hour between 0900 and 2000 h by 76 healthy volunteers (44 women, 32 men). Compliance was controlled by electronic monitors. In order to control factors which might influence the diurnal profile of salivary alpha-amylase (such as momentary stress, mood, food, or body activity), at each sampling time point the subjects filled out a diary examining the activities they had carried out during the previous hour. Results: Salivary alpha-amylase activity shows a distinct diurnal profile pattern with a pronounced decrease within 60 min after awakening and a steady increase of activity during the course of the day. Mixed models showed a relative independence of diurnal salivary alpha-amylase from momentary stress and other factors, but significant associations with chronic stress and mood.

We aimed to describe the sleep profiles and associated factors of poor sleep in adolescents. We gave a sleep questionnaire and Strengths and Difficulties Questionnaire to 3,441 high school adolescents (15-18 years) in Gaziantep, Turkey. Adolescents reported a requirement of 10.4 hours of sleep on average to feel their best during the day. However, total night sleep time (TNST) was 7.42 +/- 1.48 hours on school nights and 9.40 +/- 1.37 on non-school nights. TNST of &gt; or =9 hours on both school nights and non-school nights was detected in 8.2%. Average bedtime and wake-up time were 23:16 and 06:41 on school nights. Bedtime was approximately 30 minutes later on non-school nights. The shift in wake-up time was nearly 2.5 hours. Statistical analysis by logistic regression model showed that TNST was most significantly correlated with school start time (morning versus afternoon) irrespective of school or non-school nights. TNST on school nights was negatively correlated with age, passiv...

There is currently intense interest in the effects of macronutrients on psychological states, mental performance, and well-being. A strong theoretical perspective has guided work on carbohydrates and their relation to brain serotoninergic function with concomitant effects on performance. The clearest and most reliable effects have been observed for the beneficial action of glucose on cognitive performance, supported by investigations of hypoglycemia, which is associated with general impairment of cognitive performance. The effects of complex carbohydrates are less distinct and change with time of day; e.g., carbohydrate at breakfast tends to improve morning performance. However, these studies are rarely decisive. Far fewer experiments have been performed on protein and fat, and it is difficult to draw any firm conclusions. Macronutrients are seldom given alone, proportions of protein and fat differ greatly between studies, and comparisons are frequently performed with no food at all. Food intake may mitigate the effects of low doses but not of high doses of alcohol on performance. Effects of macronutrients on cognitive performance may be dependent on their effects on glucose metabolism, metabolic activation, or serotonin. Other factors that modify effects include time of day, circadian rhythms, type of task, habitual diet, and vulnerability of the population.

Hallucinations are perceptual phenomena involved in many fields of pathology. Although clinically widely explored, studies in the general population of these phenomena are scant. This issue was investigated using representative samples of the non-institutionalized general population of the United Kingdom, Germany and Italy Ž . aged 15 years or over N s 13 057 . These surveys were conducted by telephone and explored mental disorders and Ž hallucinations visual, auditory, olfactory, haptic and gustatory hallucinations, out-of-body experiences, hypnagogic . Ž and hypnopompic hallucinations . Overall, 38.7% of the sample reported hallucinatory experiences 19.6% less than . once in a month; 6.4% monthly; 2.7% once a week; and 2.4% more than once a week . These hallucinations Ž . Ž . Ž occurred, 1 At sleep onset hypnagogic hallucinations 24.8% andror upon awakening hypnopompic hallucinations . 6.6% , without relationship to a specific pathology in more than half of the cases; frightening hallucinations were Ž . more often the expression of sleep or mental disorders such as narcolepsy, OSAS or anxiety disorders. 2 During the Ž . Ž . daytime and reported by 27% of the sample: visual prevalence of 3.2% and auditory 0.6% hallucinations were Ž strongly related to a psychotic pathology respective OR of 6.6 and 5.1 with a conservative estimate of the lifetime . Ž . prevalence of psychotic disorders in this sample of 0.5% ; and to anxiety respective OR of 5.0 and 9.1 . Haptic Ž . hallucinations were reported by 3.1% with current use of drugs as the highest risk factor ORs 9.8 . In conclusion, the prevalence of hallucinations in the general population is not negligible. Daytime visual and auditory hallucinations are associated with a greater risk of psychiatric disorders. The other daytime sensory hallucinations are more related to an organic or a toxic disorder. ᮊ M.M. Ohayon . 0165-1781r00r$ -see front matter ᮊ 2000 Elsevier Science Ireland Ltd. All rights reserved. Ž . PII: S 0 1 6 5 -1 7 8 1 0 0 0 0 2 2 7 -4 ( ) M.M. Ohayon r Psychiatry Research 97 2000 153᎐164 154

Stress, that is, the state of threatened or perceived as threatened homeostasis, is associated with activation of the stress system, mainly comprised by the hypothalamic-pituitaryadrenal axis and the arousal/sympathetic nervous systems. The stress system normally functions in a circadian manner and interacts with other systems to regulate a variety of behavioral, endocrine, metabolic, immune, and cardiovascular functions. However, the experience of acute intense physical or emotional stress, as well as of chronic stress, may lead to the development of or may exacerbate several psychologic and somatic conditions, including anxiety disorders, depression, obesity, and the metabolic syndrome. In chronically stressed individuals, both behavioral and neuroendocrine mechanisms promote obesity and metabolic abnormalities: unhealthy lifestyles in conjunction with dysregulation of the stress system and increased secretion of cortisol, catecholamines, and interleukin-6, with concurrently elevated insulin concentrations, lead to development of central obesity, insulin resistance, and the metabolic syndrome. Fetal life, childhood, and adolescence are particularly vulnerable periods of life to the effects of intense acute or chronic stress. Similarly, these life stages are crucial for the later development of behavioral, metabolic, and immune abnormalities. Developing brain structures and functions related to stress regulation, such as the amygdala, the hippocampus, and the mesocorticolimbic system, are more vulnerable to the effects of stress compared with mature structures in adults. Moreover, chronic alterations in cortisol secretion in children may affect the timing of puberty, final stature, and body composition, as well as cause early-onset obesity, metabolic syndrome, and type 2 diabetes mellitus. The understanding of stress mechanisms leading to metabolic abnormalities in early life may lead to more effective prevention and intervention strategies of obesity-related health problems. A v a i l a b l e o n l i n e a t w w w . s c i e n c e d i r e c t . c o m Metabolism w w w . m e t a b o l i s m j o u r n a l . c o m cardiovascular function [1,2]. Both lifestyle and neuroendocrine mechanisms contribute to the development of metabolic and other alterations in stressed individuals [3].

Children with Autism Syndrome Disorders (ASDs) exhibit social, communicative, and behavioral deficits. We know that human interaction with dogs, which is thought to serve as a social catalyst, results in a decrease of cortisol levels in healthy adults. Introducing service dogs to children with ASD is an attractive idea that has received growing attention in recent decades. However, no study has measured the physiological impact of service dogs on these children. Therefore, the goal of our study was to assess the effects of service dogs on the basal salivary cortisol secretion of children with ASD. We measured the salivary cortisol levels of 42 children with ASD in three experimental conditions; prior to and during the introduction of a service dog to their family, and after a short period during which the dog was removed from their family. We compared average cortisol levels and Cortisol Awakening Response (CAR) before and during the introduction of the dog to the family and after its withdrawal. We found that the introduction of service dogs translated into a statistically significant diminished CAR. Before the introduction of service dogs, we measured a 58% increase in morning cortisol after awakening, which diminished to 10% when service dogs were present. The increase in morning cortisol jumped back to 48% once the dogs were removed from the families (p < 0.05). However, service dogs did not have an effect on the children's average diurnal cortisol levels. These results show that the CAR of children with ASD is sensitive to the presence of service dogs, which lends support to the potential behavioral benefits of service dogs for children with autism.

Dopamine (DA)-containing neurons involved in the regulation of sleep and waking (W) arise in the ventral tegmental area (VTA) and the substantia nigra pars compacta (SNc). The VTA and SNc cells have efferent and afferent connections with the dorsal raphe nucleus (DRN), the pedunculopontine and laterodorsal tegmental nuclei (PPT/LDT), the locus coeruleus (LC), the lateral and posterior hypothalamus (LH), the basal forebrain (BFB), and the thalamus. Molecular cloning techniques have enabled the characterization of two distinct groups of DA receptors, D1-like and D2-like receptors. The D1 subfamily includes the D1 and D5 receptors, whereas the D2 subfamily comprises the D2, D3, and D4 receptors. Systemic administration of a selective D1 receptor agonist induces behavioral arousal, together with an increase of W and a reduction of slow wave sleep (SWS) and REM sleep (REMS). Systemic injection of a DA D2 receptor agonist induces biphasic effects, such that low doses reduce W and increase SWS and REMS (predominant activation of the D2 autoreceptor), whereas large doses induce the opposite effect (predominant facilitation of the D2 postsynaptic receptor). Compounds with DA D1 or D2 receptor blocking properties augment non-REMS and reduce W. Preliminary findings tend to indicate that the administration of a DA D3-preferring agonist induces somnolence and sleep in laboratory animals and man. DA neurons in the VTA and the SNc do not change their mean firing rate across the sleep-wake cycle. It has been proposed that DA cells in the midbrain show a change in temporal pattern rather than firing rate during the sleep-wake cycle. The available evidence tends to indicate that during W there occurs an increase of burst firing activity of DA neurons, and an enhanced release of DA in the VTA, the nucleus accumbens (NAc), and a number of forebrain structures. A series of structures relevant for the regulation of the behavioral state, including the DRN, LDT/PPT, LC, and LH, could be partly responsible for the changes in the temporal pattern of activity of DA neurons.

A personality model based on the Big Five and their higher-order factors or metatraits was used to examine associations between personality and individual differences in circadian rhythm, as assessed by the Morningness-Eveningness Questionnaire (MEQ). Based on previous research with Eysenck's personality model and a neurobiological model implicating serotonergic function in the metatrait Stability (the shared variance of Neuroticism reversed, Agreeableness, and Conscientiousness), we hypothesized that morningness would be positively related to Stability. Structural equation modeling in a sample of 279 undergraduates confirmed this hypothesis.

D. Watson and A. Tellegen (1985) proposed a “consensual” structure of affect based on JA Russell&#x27;s (1980) circumplex. The authors&#x27; review of the literature indicates that this 2-factor model captures robust structural properties of self-rated mood. Nevertheless, the evidence also indicates ...

Identifying road accident hotspots is a key role in determining effective strategies for the reduction of high density areas of accidents. This paper presents (1) a methodology using Geographical Information Systems (GIS) and Kernel Density Estimation to study the spatial patterns of injury related road accidents in London, UK and (2) a clustering methodology using environmental data and results from the first section in order to create a classification of road accident hotspots. The use of this methodology will be illustrated using the London area in the UK. Road accident data collected by the Metropolitan Police from 1999 to 2003 was used. A kernel density estimation map was created and subsequently disaggregated by cell density to create a basic spatial unit of an accident hotspot. Appended environmental data was then added to the hotspot cells and using K-means clustering, an outcome of similar hotspots was deciphered. Five groups and 15 clusters were created based on collision and attribute data. These clusters are discussed and evaluated according to their robustness and potential uses in road safety campaigning.

Humans are a diurnal species usually exposed to light while engaged in cognitive tasks. Light not only guides performance on these tasks through vision but also exerts non-visual effects that are mediated in part by recently discovered retinal ganglion cells maximally sensitive to blue light. We review recent neuroimaging studies which demonstrate that the wavelength, duration and intensity of light exposure modulate brain responses to (nonvisual) cognitive tasks. These responses to light are initially observed in alertness-related subcortical structures (hypothalamus, brainstem, thalamus) and limbic areas (amygdala and hippocampus), followed by modulations of activity in cortical areas, which can ultimately affect behaviour. Light emerges as an important modulator of brain function and cognition.

Close attention to patients treated with morphine or drugs derived from it can accelerate the diagnosis of the Opioid Induced Neurotoxicity Syndrome (OIN). It may allow the application of some therapeutic measures that provide hopeful results.

Epilepsy and sleep disorders are considered by many to be common bedfellows. Several sleep phenomena may occur during nighttime taking a wide variety of forms and which can mimic seizures. Although most seizure sub-types have the potential to occur during sleep or wakefulness, sleep has a well-documented and strong association with specific epilepsy syndromes. Seizures in sleep also tend to occur during lighter stages of non-REM (NREM) sleep. The neurophysiologic process involved in the deepening of NREM sleep may also facilitate both seizures and IEDs. Epilepsy per se and/or seizures themselves promote sleep disruption and significantly affect the quality, quantity, and architecture of sleep. There are many causes of sleep disruption in patients with epilepsy, including inadequate sleep hygiene, coexisting sleep disorders, and circadian rhythm disturbances. Seizures themselves can disrupt sleep, even when they occur during wakefulness. Anti-epileptic drugs (AEDs) can also alter sleep in positive and negative ways, and these effects are independent of anticonvulsant actions. The end result of sleep disruption is excessive daytime sleepiness, worsening seizures, and poor quality of life. Screening for sleep disorders in the epilepsy population and appropriate intervention strategies will lead to overall improved quality of life and seizure control.