Ambulatory sleep-wake patterns and variability in young people with emerging mental disorders.

BACKGROUND: The nature of sleep-wake abnormalities in individuals with mental disorders remains unclear. The present study aimed to examine the differences in objective ambulatory measures of the sleep-wake and activity cycles across young people with anxiety, mood or psychotic disorders. METHODS: Participants underwent several days of actigraphy monitoring. We divided participants into 5 groups (control, anxiety disorder, unipolar depression, bipolar disorder, psychotic disorder) according to primary diagnosis. RESULTS: We enrolled 342 participants aged 12-35 years in our study: 41 healthy controls, 56 with anxiety disorder, 135 with unipolar depression, 80 with bipolar disorder and 30 with psychotic disorders. Compared with the control group, sleep onset tended to occur later in the anxiety, depression and bipolar groups; sleep offset occurred later in all primary diagnosis groups; the sleep period was longer in the anxiety, bipolar and psychosis groups; total sleep time was longer in the psychosis group; and sleep efficiency was lower in the depression group, with a similar tendency for the anxiety and bipolar groups. Sleep parameters were significantly more variable in patient subgroups than in controls. Cosinor analysis revealed delayed circadian activity profiles in the anxiety and bipolar groups and abnormal circadian curve in the psychosis group. LIMITATIONS: Although statistical analyses controlled for age, the sample included individuals from preadolescence to adulthood. Most participants from the primary diagnosis subgroups were taking psychotropic medications, and a large proportion had other comorbid mental disorders. CONCLUSION: Our findings suggest that delayed and disorganized sleep offset times are common in young patients with various mental disorders. However, other sleep-wake cycle disturbances appear to be more prominent in broad diagnostic categories.

Napping in older people 'at risk' of dementia: relationships with depression, cognition, medical burden and sleep quality.

Sleep disturbance is prevalent in older adults, particularly so in those at a greater risk of dementia. However, so far the clinical, medical and neuropsychological correlates of daytime sleep have not been examined. The aims of this study were to investigate the characteristics and effects of napping using actigraphy in older people, particularly in those 'at risk' of dementia. The study used actigraphy and sleep diaries to measure napping habits in 133 older adults 'at risk' of dementia (mean age = 65.5 years, SD = 8.4 years), who also underwent comprehensive medical, psychiatric and neuropsychological assessment. When defined by actigraphy, napping was present in 83.5% (111/133) of participants; however, duration and timing varied significantly among subjects. Nappers had significantly greater medical burden and body mass index, and higher rates of mild cognitive impairment. Longer and more frequent naps were associated with poorer cognitive functioning, as well as higher levels of depressive symptoms, while the timing of naps was associated with poorer nocturnal sleep quality (i.e. sleep latency and wake after sleep onset). This study highlights that in older adults 'at risk' of dementia, napping is associated with underlying neurobiological changes such as depression and cognition. Napping characteristics should be more routinely monitored in older individuals to elucidate their relationship with psychological and cognitive outcomes.

Actigraphic and melatonin alignment in older adults with varying dementia risk.

Circadian rhythms alter with ageing and may be aetiologically linked to neurodegeneration. This study explored the association between clinical markers and 1) dim light melatonin onset (DLMO) time and 2) phase angle derived from sleep midpoint, in older adults with varying dementia risks. Participants completed 14 days of actigraphy followed by in-lab measurement of salivary melatonin, from which DLMO time and phase angle were computed. Eighty participants (age = 65.5, SD = 9.6), 44 males (55%), MMSE (28.6, SD = 1.5) were included in the analysis. Sex (t = 2.15, p = .04), sleep onset (r = 0.49, p < .001) and midpoint (r = 0.44, p < .001) also correlated with DLMO time. Multiple linear regression showed chronotype, average actigraphy-derived light exposure during the DLMO window (window 2 h prior to DLMO to 2 h post), early biological day (6-10 h post DLMO time) and late biological day (10-14 h post DLMO time) were predictive of DLMO time (adjusted R2 = 0.75). Sleep offset, depression severity, average light exposure during the early biological night and early and late biological day were shown to be predictive variables in the estimation of phase angle (adjusted R2 = 0.78). The current study highlights the potential use of clinical variables, such as actigraphy-derived light, as circadian markers in ageing which could be easily implemented into existing clinical practice and could yield potential targets focusing on chronotherapeutic interventions.

Novel melatonin-based therapies: potential advances in the treatment of major depression.

Major depression is one of the leading causes of premature death and disability. Although available drugs are effective, they also have substantial limitations. Recent advances in our understanding of the fundamental links between chronobiology and major mood disorders, as well as the development of new drugs that target the circadian system, have led to a renewed focus on this area. In this review, we summarise the associations between disrupted chronobiology and major depression and outline new antidepressant treatment strategies that target the circadian system. In particular, we highlight agomelatine, a melatonin-receptor agonist and selective serotonergic receptor subtype (ie, 5-HT(2C)) antagonist that has chronobiotic, antidepressant, and anxiolytic effects. In the short-term, agomelatine has similar antidepressant efficacy to venlafaxine, fluoxetine, and sertraline and, in the longer term, fewer patients on agomelatine relapse (23·9%) than do those receiving placebo (50·0%). Patients with depression treated with agomelatine report improved sleep quality and reduced waking after sleep onset. As agomelatine does not raise serotonin levels, it has less potential for the common gastrointestinal, sexual, or metabolic side-effects that characterise many other antidepressant compounds.

Can older "at risk" adults benefit from psychoeducation targeting healthy brain aging?

BACKGROUND: Multifactorial strategies that prevent or delay the onset or progress of cognitive decline and dementia are needed, and should include education regarding recognized risk factors. The current study sought to investigate whether older adults "at risk" of cognitive decline benefit from psychoeducation targeting healthy brain aging. METHODS: 65 participants (mean age 64.8 years, SD 9.6) with a lifetime history of major depression; vascular risk as evidenced by at least one vascular risk factor; and/or subjective or objective memory impairment were allocated to weekly psychoeducation sessions or a waitlist control group. The small group sessions were conducted over ten weeks by a team of medical and allied health professionals with expertise in late-life depression and cognition. Sessions focused on modifiable risk factors for cognitive decline including vascular risk, diet, exercise, depression, anxiety and sleep disturbance, as well as providing practical strategies for memory and cognition. Both the psychoeducation and waitlist group completed a 20-item knowledge test at baseline and follow-up. Participants in the psychoeducation group were asked to complete follow-up self-report satisfaction questionnaires. RESULTS: Repeated measures ANOVA showed a significant interaction effect depicting improvements in knowledge associated with psychoeducation, corresponding to an improvement of 15% from baseline. Satisfaction data additionally showed that 92.3% of participants rated the program as "good" to "excellent", and over 90% suggested they would recommend it to others. CONCLUSIONS: A group-based psychoeducation program targeting healthy brain aging is effective in improving knowledge. Additionally, it is acceptable and rated highly by participants.

Modafinil effects during acute continuous positive airway pressure withdrawal: a randomized crossover double-blind placebo-controlled trial.

RATIONALE: Continuous positive airway pressure (CPAP) use is associated with reduced motor vehicle accidents in patients with obstructive sleep apnea (OSA). However, interruption of CPAP therapy is common and is associated with a decline in daytime function. OBJECTIVES: We hypothesized that the wakefulness promoter, modafinil, would ameliorate this decline. METHODS: Patients were admitted to the laboratory for three consecutive nights. CPAP was used for the first night, followed by a baseline day, and was then withdrawn for the two subsequent nights (nasal airflow monitored). On each of the mornings after the two CPAP withdrawal nights, patients received 200 mg modafinil or placebo (n = 21) in a randomized, double-blind, crossover design. Treatment periods were separated by a 5-week washout. Driving simulator performance, neurocognitive performance, and subjective alertness were measured by the AusEd driving simulator, psychomotor vigilance task, and Karolinska Sleepiness Scale, respectively. MEASUREMENTS AND MAIN RESULTS: During CPAP withdrawal, severe sleep-disordered breathing was evident and administration of modafinil improved simulated driving performance (steering variability, P < 0.0001; mean reaction time, P

Sleep well, think well: sleep-wake disturbance in mild cognitive impairment.

While literature suggests that sleep is important for cognition and mood, and that sleep disturbance is a prominent feature of neurodegenerative and neuropsychiatric disorders, these relationships have not yet been examined in older people ''at risk" of dementia. In this study, 15 older people with the nonamnestic subtype of mild cognitive impairment ([MCI] mean age = 66.7 years, SD = 8.7) underwent psychiatric and neuropsychological assessment. Participants completed sleep diaries, questionnaires, and 2 weeks of actigraphy. Key outcome data during the rest interval were time spent ''awake" or wake after sleep onset (WASO) and the number of arousals/wake bouts. Results showed that even after controlling for age, greater WASO was associated with reduced attention and executive functioning and increased arousals were related to poorer nonverbal learning and problem solving. This preliminary data suggests that sleep-wake disturbance in nonamnestic forms of MCI is related to cognitive functioning and may be indicative of shared neurobiological underpinnings.

Time of day effects on neurobehavioral performance during chronic sleep restriction.

INTRODUCTION: Chronic nocturnal sleep restriction results in accumulation of neurobehavioral impairment across days. The purpose of this study was to determine whether time of day modulates the effects of sleep restriction on objective daytime performance deficits and subjective sleepiness across days of chronic sleep restriction. METHODS: There were N = 90 healthy adults (21-49 yr; 38 women) who participated in a 14-d laboratory protocol involving randomization to 1 of 18 schedules of restricted nocturnal sleep with and without a diurnal nap for 10 consecutive days. The total time available for daily sleep ranged from 4.2 h to 8.2 h across conditions. Performance lapses on the psychomotor vigilance test (PVT) and subjective sleepiness were measured each day every 2 h during scheduled wakefulness. Nonlinear mixed-effects regression was used to test the hypothesis that there would be an interaction between time of day and the accumulation (slope across days) of neurobehavioral sleepiness. RESULTS: In agreement with earlier studies, less sleep time resulted in faster accumulation of deficits across days. Time of day significantly affected this relationship for both PVT lapses and subjective sleepiness. The build-up rate of cumulative neurobehavioral deficits across days was largest at 0800 and became progressively smaller across the hours of the day, especially between 1600 and 2000. Following 8 d of sleep restricted to 4 h/d, subjects averaged 8.3 more PVT performance lapses at 0800 than at 1800. DISCUSSION: This study provides evidence that the circadian system has a substantial modulatory effect on cumulative impairment from chronic sleep restriction and that it facilitates a period of relatively protected alertness in the late afternoon/early evening hours when nocturnal sleep is chronically restricted.

Circadian rhythm profiles in women with night eating syndrome.

Night eating syndrome (NES) is characterized by evening hyperphagia and frequent awakenings accompanied by food intake. Patients with NES display a delayed circadian pattern of food intake but retain a normal sleep-wake cycle. These characteristics initiated the current study, in which the phase and amplitude of behavioral and neuroendocrine circadian rhythms in patients with NES were evaluated. Fifteen women with NES (mean age +/- SD, 40.8 +/- 8.7 y) and 14 control subjects (38.6 +/- 9.5 y) were studied in the laboratory for 3 nights, with food intake measured daily. Blood also was collected for 25 h (every 2 h from 0800 to 2000 h, and then hourly from 2100 to 0900 h) and assayed for glucose and 7 hormones (insulin, ghrelin, leptin, melatonin, cortisol, thyroid-stimulating hormone [TSH] and prolactin). Statistical analyses utilized linear mixed-effects cosinor analysis. Control subjects displayed normal phases and amplitudes for all circadian rhythms. In contrast, patients with NES showed a phase delay in the timing of meals, and delayed circadian rhythms for total caloric, fat, and carbohydrate intake. In addition, phase delays of 1.0 to 2.8 h were found in 2 food-regulatory rhythms-leptin and insulin-and in the circadian melatonin rhythm (with a trend for a delay in the circadian cortisol rhythm). In contrast, circulating levels of ghrelin, the primary hormone that stimulates food intake, were phase advanced by 5.2 h. The glucose rhythm showed an inverted circadian pattern. Patients with NES also showed reduced amplitudes in the circadian rhythms of food intake, cortisol, ghrelin, and insulin, but increased TSH amplitude. Thus, patients with NES demonstrated significant changes in the timing and amplitude of various behavioral and physiological circadian markers involved in appetite and neuroendocrine regulation. As such, NES may result from dissociations between central (suprachiasmatic nucleus) timing mechanisms and putative oscillators elsewhere in the central nervous system or periphery, such as the stomach or liver. Considering these results, chronobiologic treatments for NES such as bright light therapy may be useful. Indeed, bright light therapy has shown efficacy in reducing night eating in case studies and should be evaluated in controlled clinical trials.

Interaction of chronic sleep restriction and circadian system in humans.

Nocturnal sleep restriction and compensation with daytime naps is common in today's society. In a between-participants design, we examined the effects of chronic (10 nights) sleep restriction on 24 h plasma melatonin profiles in humans. Following a baseline period with 8.2 h time in bed (TIB) for sleep, participants were randomized to a control (8.2 h TIB) or sleep-restriction condition (4.2 h TIB), with and without diurnal naps. Sleep restriction was achieved via delaying bedtime and advancing wake time by 2 h each relative to the baseline sleep period. Participants were maintained in a controlled, time isolated laboratory environment throughout the protocol, with light levels below 40 lx at all times. Twenty-four hour plasma melatonin profiles were assessed at baseline and at the end of the sleep-restriction period, with subjects maintained in a constant posture protocol. Compared with the baseline assessment and the 8.2 h TIB control group, a significant phase delay in melatonin onset (1.2 +/- 0.9 h) occurred in all sleep-restriction (4.2 h TIB) groups (P < 0.05). There was no evidence of a phase advance or shortening of the period of melatonin secretion associated with the advanced waking time. These results suggest that nocturnal light and dark exposure may be more potent in effecting circadian phase shifts than exposure to morning light, at least in conditions of controlled, dim lighting in the laboratory.

Comparing the neurocognitive effects of 40 h sustained wakefulness in patients with untreated OSA and healthy controls.

We hypothesized that individuals with untreated obstructive sleep apnea (OSA) would exhibit greater vulnerability to sleep deprivation than healthy controls, due to the additional neurobiological 'load' of chronic sleep fragmentation. After baseline sleep with 8 h time in bed, participants remained awake for 40 h. Psychomotor Vigilance Task (PVT, mean slowest 10% 1/RT), AusEd Driving Simulator task (steering and speed deviation), and subjective sleepiness (Karolinska Sleepiness Scale, KSS) were assessed every 2 h. Nonlinear mixed-effects models were used to characterize individual differences in baseline/average performance, the linear effect of increasing hours awake, circadian amplitude and phase. Eight participants with untreated OSA with mean (SD) age 44.6 (8.4), apnea-hypopnea index (AHI) 49.8 (24.7), Epworth Sleepiness Scale (ESS) 11.9 (4.8) and nine healthy controls age 27.8 (3.7), AHI 4.5 (2.7), ESS 7.3 (2.1) completed the protocol. Baseline KSS was significantly higher (1.4 units, P = 0.03) in the OSA group and there was a trend toward lower baseline speed deviation on the AusEd (P = 0.05). After adjusting for the significant effects of accumulated time awake, circadian amplitude and phase (all P < 0.005), there was no difference in performance decrements between those with and without sleep apnea in PVT, driving simulator performance and subjective sleepiness (P > 0.5). Random-effects modeling confirmed the presence of significant inter-individual variability in vulnerability to sleep deprivation. Patients with OSA did not respond differently to sleep deprivation than healthy controls. As expected, total sleep deprivation led to significant worsening in performance and subjective sleepiness in both groups.

Response Surface Mapping of Neurobehavioral Performance: Testing the Feasibility of Split Sleep Schedules for Space Operations.

The demands of sustaining high levels of neurobehavioral performance during space operations necessitate precise scheduling of sleep opportunities in order to best preserve optimal performance. We report here the results of the first split-sleep, dose-response experiment involving a range of sleep/wake scenarios with chronically reduced nocturnal sleep, augmented with a diurnal nap. To characterize performance over all combinations of split sleep in the range studied, we used response surface mapping methodology. Waking neurobehavioral performance was studied in N=90 subjects each assigned to one of 18 sleep regimens consisting of a restricted nocturnal anchor sleep period and a diurnal nap. Psychomotor vigilance task performance and subjective assessments of sleepiness were found to be primarily a function of total time in bed per 24 h regardless of how sleep was divided among nocturnal anchor sleep and diurnal nap periods. Digit symbol substitution task performance was also found to be primarily a function of total time in bed per 24 h; however, accounting for nocturnal sleep duration and nap duration separately provided a small but significant enhancement in the variance explained. The results suggest that reductions in total daily sleep result in a near-linear accumulation of impairment regardless of whether sleep is scheduled as a consolidated nocturnal sleep period or split into a nocturnal anchor sleep period and a diurnal nap. Thus, split sleep schedules are feasible and can be used to enhance the flexibility of sleep/work schedules for space operations involving restricted nocturnal sleep due to mission-critical task scheduling. These results are generally applicable to any continuous industrial operation that involves sleep restriction, night operations, and shift work.

Circadian rhythms and psychiatric profiles in young adults with unipolar depressive disorders.

Abnormalities in circadian rhythms have been reported in people with mood disorders, but these abnormalities are marked by considerable inter-individual variability. This study aimed to identify pathophysiological subgroups on the basis of circadian markers and evaluate how these subgroups relate to psychiatric profiles. Thirty-five young adults (18-31 years old) receiving clinical care for unipolar depressive disorders and 15 healthy controls took part to this study. The Hamilton Rating Scale for Depression and the Young Mania rating scale were used to evaluate the severity of mood symptoms in participants with depressive disorders. All participant underwent ambulatory sleep monitoring with actigraphy for about 12 days before attending a laboratory-based chronobiological assessment which included repeated salivary samples to determine dim light melatonin onset (DLMO) and continuous core body temperature (CBT) monitoring using an ingestible temperature sensor. Cluster analyses were conducted across all participants to identify subgroups with consistent circadian timing profiles based on DLMO and the nocturnal minima of CBT. Two clusters were identified: 'delayed' and 'conventional timing' circadian phase. Descriptive analyses showed that the delayed cluster was characterised by abnormal time relationships between circadian phase markers and the sleep-wake cycle. Importantly, individuals from the delayed cluster had worse depression severity (t(28) = -2.7, p = 0.011) and hypomanic symptoms (Z = -2.2, p = 0.041) than their peers with conventional circadian timing. These findings suggest that delayed and disorganised circadian rhythms may be linked to worse psychiatric profiles in young people with depressive disorders.

A systematic review of the neurobehavioural and physiological effects of shiftwork systems.

Shiftwork is a common experience for many workers. There are a wide range of shift systems in use, with a number of general approaches and myriad variations of each one. Many aspects of shift systems have been studied, but attempts to reach definitive conclusions about appropriate designs have been hampered by a number of methodological issues. The aim of this systematic review was to provide evidence-based recommendations on the effect of various shift systems on neurobehavioural and physiological functioning and to identify areas which are lacking in appropriate evidence. Two main aspects of shift design were able to be considered-the direction of shift rotation and extended shift length (mainly 12-h shifts). Other areas for which there was at least one relevant paper of adequate methodology were the use of naps during night shifts, the starting time of shifts, and several other specific shift issues. Overall, the review found there is insufficient evidence to support definitive conclusions regarding any of these factors. However, the analysis provides support for the use of forward rotating shift systems in preference to backward rotating shift systems, at last as far as 8-h shifts are concerned. There are many unanswered questions in shift design. For these questions to be answered, it is important that the methodological shortcomings present in most of the studies published to date be overcome.

Thermoregulatory changes around the time of sleep onset.

A causal relationship between declining nocturnal core temperature, increasing peripheral temperature, and sleep onset has been reported. The exact trigger for these thermoregulatory changes around sleep onset, however, is unknown. Our aim was to examine one possible trigger: prior knowledge of bedtime. Fourteen young, healthy male subjects (mean age+/-sem: 21.9+/-0.6 years), participated in a randomized, single-blind crossover study, where knowledge of bedtime was manipulated. Following a baseline night, subjects completed three experimental nights: (A) aware of bedtime; (B) no knowledge of bedtime; (C) misinformed about bedtime. In all conditions lights were turned off at each subject's habitual bedtime (determined from sleep diaries), to individually standardize the time of lights off. Polysomnography, rectal and peripheral (foot) temperatures were recorded continuously on each night. There was no significant difference in the time of sleep onset among conditions (mean+/-s.d.: 11:55 h+/-0.73 min), and in all conditions sleep onset occurred at the same rectal temperature. A significant difference in the temperature gradient between rectal and peripheral temperatures among the conditions was evident from 90 min to 40 min prior to sleep onset (P=0.05), with subjects achieving a more rapid rate of temperature change in the B and C condition relative to condition A. The present findings suggest that knowledge of bedtime may modulate changes in temperature around the time of sleep onset. It appears that there is an optimal core body temperature at which to initiate sleep, and changes in the rate of peripheral heat loss may assist in achieving this optimal temperature, and hence facilitate sleep onset.

Lower In vivo Myo-Inositol in the Anterior Cingulate Cortex Correlates with Delayed Melatonin Rhythms in Young Persons with Depression.

Myo-inositol, a second messenger glucose isomer and glial marker, is potentiated by melatonin. In addition to common abnormalities in melatonin regulation, depressive disorders have been associated with reduced myo-inositol in frontal structures. This study examined associations between myo-inositol in the anterior cingulate cortex and the timing of evening melatonin release. Forty young persons with unipolar depression were recruited from specialized mental health services (20.3 ± 3.8 years old). Healthy controls were recruited from the community (21.7 ± 2.6 years old). The timing of dim light melatonin onset (DLMO) was estimated using salivary melatonin sampling. Myo-inositol concentrations (MI/CrPCr ratio) in the anterior cingulate cortex were obtained using proton magnetic resonance spectroscopy. After controlling for age, sex, and CrPCr concentration the depression group had significantly lower MI/CrPCr ratios than healthy controls [F(4, 75) = 11.4, p = 0.001]. In the depression group, later DLMO correlated with lower MI/CrPCr ratio (r = -0.48, p = 0.014). These findings suggest that neurochemical changes in the frontal cortex are associated with circadian disruptions in young persons with depression.

Effects of short-term CPAP withdrawal on neurobehavioral performance in patients with obstructive sleep apnea.

STUDY OBJECTIVE: Changes in sleep parameters and neurobehavioral functioning were systematically investigated after an acute (1 night) and short-term (7 nights) period of withdrawal from continuous positive airway pressure (CPAP) treatment and 1 subsequent night of CPAP reintroduction in patients with obstructive sleep apnea. DESIGN: Repeated-measurement within-subject design. SETTING: Sleep laboratory, university teaching hospital. PARTICIPANTS: Twenty participants receiving optimal CPAP therapy for > or = 12 months. INTERVENTIONS: CPAP withdrawal. MEASUREMENTS AND RESULTS: Polysomnograms were performed on Night 0 (with CPAP), Night 1 and Night 7 (without CPAP) and Night 8_R (with CPAP). Acute CPAP withdrawal resulted in the recurrence of sleep-disordered breathing with sleep disruption, hypoxemia, and increased subjective sleepiness. Short-term CPAP withdrawal exacerbated hypoxemia, increased subjective and objective sleepiness and poor mood ratings. Neurobehavioral functioning assessed using the Psychomotor Vigilance Task was impaired following Night 7 and associated with hypoxemia and changes in morning levels of tumor necrosis factor-alpha. However, other neurobehavioral measures were not affected. Autonomic arousals measured via respiratory-related reductions in finger blood volume by peripheral arterial tonometry decreased from Night 1 to Night 7. On Night 8_R, reintroduction of CPAP treatment eliminated most airway obstruction, maintained oxygenation, and reversed daytime sleepiness and some vigilance decrements. CONCLUSION: Despite recurrence of sleep-disordered breathing with increased sleepiness and impaired vigilance, most neurobehavioral variables were unaffected by CPAP withdrawal. The reduction in vigilance appeared to be associated with worsened hypoxemia and changed levels of tumor necrosis factor-alpha. Resumption of CPAP treatment had immediate benefits on sleep consolidation and subjective sleepiness.

Assessment of sleep in women with night eating syndrome.

STUDY OBJECTIVES: Evaluation of sleep in subjects with night eating syndrome (NES). DESIGN: Polysomnographic and questionnaire comparisons between subjects with NES and controls. SETTING AND PARTICIPANTS: Fifteen women with NES (mean +/- SD = 41 +/- 8 years) and 14 women (comparable age and weight) without NES (39 +/- 10 years) were studied in the laboratory for 3 days. INTERVENTIONS: N/A. MEASUREMENTS AND RESULTS: Subjects with NES did not differ from controls in timing of sleep onset or offset. They had less stage 2 sleep than controls (minutes, p = .012; percentage, p = .016) and less stage 3 sleep (p = .023), which contributed to their having a lower total sleep time (p = .05) and reduced sleep efficiency (p = .03). Subjects with NES did not have more awakenings than controls, but 93.3% of them ate on awakening during all 3 nights, while 92.9% of controls did not eat on any night. Logistic discriminant analyses identified a multiple sleep parameter model associated with increased likelihood of NES that had sensitivity of 84.6% and specificity of 76.9%. Patients with NES were more depressed than controls (p < .001) and reported greater sleep disturbance that included lower sleep quality (p < or = .001), reduced sleep duration (p < or = .001), and increased number of awakenings (p < or = .001). CONCLUSIONS: Patients with NES appear to have sleep maintenance insomnia rather than sleep-related eating disorder or a parasomnia. The maintenance of normal timing for sleep-wake behavior in the presence of a phase delay in the timing of caloric intake suggests this disorder reflects a state of internal circadian desynchrony associated with significant sleep complaints. It remains unknown whether the sleep disturbance precedes the abnormally timed eating.

Dysregulated sleep-wake cycles in young people are associated with emerging stages of major mental disorders.

AIM: To determine if disturbed sleep-wake cycle patterns in young people with evolving mental disorder are associated with stages of illness. METHODS: The sleep-wake cycle was monitored using actigraphy across 4 to 22 days. Participants (21 healthy controls and 154 persons seeking help for mental health problems) were aged between 12 and 30 years. Those persons seeking mental health care were categorized as having mild symptoms (stage 1a), an 'attenuated syndrome' (stage 1b) or an 'established mental disorder' (stage 2+). RESULTS: The proportions of individuals with a delayed weekdays sleep schedule increased progressively across illness stages: 9.5% of controls, 11.1% of stage 1a, 25.6% of stage 1b, and 50.0% of stage 2+ (χ(2) (3 d.f.) = 18.4, P < 0.001). A similar pattern was found for weekends (χ(2) (3 d.f.) = 7.6, P = 0.048). Compared with controls, stage 1b participants had later sleep onset on weekends (P = 0.015), and participants at stages 1b and 2+ had later sleep offset on both weekdays and weekends (P < 0.020). Compared with controls, all participants with mental disorders had more wake after sleep onset (P < 0.029) and those at stages 1a and 2+ had lower sleep efficiency (P < 0.040). Older age, medicated status and later weekdays sleep offset were found to be the three strongest correlates of later versus earlier clinical stages. CONCLUSIONS: In relation to clinical staging of common mental disorders in young people, the extent of delayed sleep phase is associated with more severe or persistent phases of illness.

Optical computer recognition of facial expressions associated with stress induced by performance demands.

Application of computer vision to track changes in human facial expressions during long-duration spaceflight may be a useful way to unobtrusively detect the presence of stress during critical operations. To develop such an approach, we applied optical computer recognition (OCR) algorithms for detecting facial changes during performance while people experienced both low- and high-stressor performance demands. Workload and social feedback were used to vary performance stress in 60 healthy adults (29 men, 31 women; mean age 30 yr). High-stressor scenarios involved more difficult performance tasks, negative social feedback, and greater time pressure relative to low workload scenarios. Stress reactions were tracked using self-report ratings, salivary cortisol, and heart rate. Subjects also completed personality, mood, and alexithymia questionnaires. To bootstrap development of the OCR algorithm, we had a human observer, blind to stressor condition, identify the expressive elements of the face of people undergoing high- vs. low-stressor performance. Different sets of videos of subjects' faces during performance conditions were used for OCR algorithm training. Subjective ratings of stress, task difficulty, effort required, frustration, and negative mood were significantly increased during high-stressor performance bouts relative to low-stressor bouts (all p < 0.01). The OCR algorithm was refined to provide robust 3-d tracking of facial expressions during head movement. Movements of eyebrows and asymmetries in the mouth were extracted. These parameters are being used in a Hidden Markov model to identify high- and low-stressor conditions. Preliminary results suggest that an OCR algorithm using mouth and eyebrow regions has the potential to discriminate high- from low-stressor performance bouts in 75-88% of subjects. The validity of the workload paradigm to induce differential levels of stress in facial expressions was established. The paradigm also provided the basic stress-related facial expressions required to establish a prototypical OCR algorithm to detect such changes. Efforts are underway to further improve the OCR algorithm by adding facial touching and automating application of the deformable masks and OCR algorithms to video footage of the moving faces as a prelude to blind validation of the automated approach.