Eveningness and poor sleep quality contribute to depressive residual symptoms and behavioral inhibition in patients with bipolar disorder

ABSTRACT

Eveningness and sleep disturbances are considered as markers of Bipolar Disorder (BD) and influence mood and emotional or behavioral states. This study investigates the associations between circadian markers and sleep quality on residual depressive symptoms and inhibition/activation dimensions during the euthymic phase. A sample of 89 euthymic adult individuals with BD was assessed for circadian preference and typology using the Composite Scale of Morningness (CSM) and the Circadian Type Inventory (CTI) and for sleep quality using the Pittsburgh Sleep Quality Index (PSQI). The Montgomery and Asberg Depression Rating Scale (MADRS) and the Multidimensional Assessment of Thymic States (MAThyS) were used to measure residual depressive symptoms and the inhibition/activation dimensions. We examined any associations between these parameters using correlations and path analyses. We identified significant associations between eveningness and poorer sleep quality that correlated to higher depressive residual symptoms and a global inhibition. The use of path analyses led us to conclude that poor sleep quality mediated the relationship between eveningness and either residual mood symptoms or behavioral inhibition (motivation, sensory perception, interpersonal interaction, and cognition). These factors should be considered in the clinical evaluation of individuals with BD, with a specific attention during the euthymic phase, in order to achieve the best functional outcome possible.     

Circadian preference and sleep-wake regularity: associations with self-report sleep parameters in daytime-working adults

The aim of this study was to explore how interindividual differences in circadian type (morningness) and sleep timing regularity might be related to subjective sleep quality and quantity. Self-report circadian phase preference, sleep timing, sleep quality, and sleep duration were assessed in a sample of 62 day-working adults (33.9% male, age 23?48 yrs). The Pittsburgh Sleep Quality Index (PSQI) measured subjective sleep quality and the Sleep Timing Questionnaire (STQ) assessed habitual sleep latency and minutes awake after sleep onset. The duration, timing, and stability of sleep were assessed using the STQ separately for work-week nights (Sunday?Thursday) and for weekend nights (Friday and Saturday). Morningness-eveningness was assessed using the Composite Scale of Morningness (CSM). Daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS). A morning-type orientation was associated with longer weekly sleep duration, better subjective sleep quality, and shorter sleep-onset latency. Stable weekday rise-time correlated with better self-reported sleep quality and shorter sleep-onset latency. A more regular weekend bedtime was associated with a shorter sleep latency. A more stable weekend rise-time was related to longer weekday sleep duration and lower daytime sleepiness. Increased overall regularity in rise-time was associated with better subjective sleep quality, shorter sleep-onset latency, and higher weekday sleep efficiency. Finally, a morning orientation was related to increased regularity in both bedtimes and rise-times. In conclusion, in daytime workers, a morning-type orientation and more stable sleep timing are associated with better subjective sleep quality. (Author correspondence: asoehner@berkeley.edu ).     

Circadian Preference and Sleep-Wake Regularity: Associations With Self-Report Sleep Parameters in Daytime-Working Adults

The aim of this study was to explore how interindividual differences in circadian type (morningness) and sleep timing regularity might be related to subjective sleep quality and quantity. Self-report circadian phase preference, sleep timing, sleep quality, and sleep duration were assessed in a sample of 62 day-working adults (33.9% male, age 23–48 yrs). The Pittsburgh Sleep Quality Index (PSQI) measured subjective sleep quality and the Sleep Timing Questionnaire (STQ) assessed habitual sleep latency and minutes awake after sleep onset. The duration, timing, and stability of sleep were assessed using the STQ separately for work-week nights (Sunday–Thursday) and for weekend nights (Friday and Saturday). Morningness-eveningness was assessed using the Composite Scale of Morningness (CSM). Daytime sleepiness was measured using the Epworth Sleepiness Scale (ESS). A morning-type orientation was associated with longer weekly sleep duration, better subjective sleep quality, and shorter sleep-onset latency. Stable weekday rise-time correlated with better self-reported sleep quality and shorter sleep-onset latency. A more regular weekend bedtime was associated with a shorter sleep latency. A more stable weekend rise-time was related to longer weekday sleep duration and lower daytime sleepiness. Increased overall regularity in rise-time was associated with better subjective sleep quality, shorter sleep-onset latency, and higher weekday sleep efficiency. Finally, a morning orientation was related to increased regularity in both bedtimes and rise-times. In conclusion, in daytime workers, a morning-type orientation and more stable sleep timing are associated with better subjective sleep quality. (Author correspondence: asoehner@berkeley.edu)     

Chronotypes of Bipolar Patients in Remission: Validation of the French Version of the Circadian Type Inventory in the FACE-BD Sample

Circadian rhythm disturbances have been associated with bipolar disorder (BD) during both the mood episodes and the periods of remission. Circadian phase preferences for the evening have been reported for remitted patients, whereas the amplitude and stability of their rhythms have never been assessed using questionnaires. The primary aim of our study was the validation of a French version of the Circadian Type Inventory (CTI), whereas its secondary aim was the comparison between remitted patients with BD and healthy controls for rhythm stability and amplitude and for phase preference. For this purpose, we used the CTI and the Composite Scale of Morningness (CSM) that assesses phase preference (“morning” or “evening” type). First, we report here on the validation of the French version of the 11-item Circadian Type Inventory in a sample of 140 remitted patients with BD and 156 healthy controls. Principal components analysis revealed a two-factor structure (FR: flexibility/rigidity scale corresponding to rhythm stability; LV: languid/vigorous scale corresponding to rhythm amplitude) explaining 52% of the variance in the control group and 47% in the bipolar group. Cronbach’s alpha was 0.75 for FR and 0.73 for LV. The test-retest reliability was 0.74 for FR and 0.86 for LV (3 wks) and 0.62 for FR and 0.72 for LV (6 mos). LV and FR scores correlated with the Composite Scale of Morningness score (p?<?0.00001 and p?=?0.0002, respectively). Second, as compared with controls, patients with BD were more languid (p?<?0.00001) and showed an evening preference (p?=?0.0003), but they did not differ from the controls with regard to flexibility/rigidity. The French version of the CTI appeared to have satisfactory psychometrics characteristics. Bipolar patients exhibited not only abnormalities in phase preference but also in amplitude as measured by languidity. Since circadian rhythm dysfunction has been shown to predict poor functioning and mood relapses in interepisodic patients with BD, this tool would appear to be a promising, easy-to-use, measure of the amplitude and flexibility of circadian rhythms that could enrich the arsenal of assessments used in clinical settings.     

Personality correlates with sleep-wake variables

A mail-in questionnaire study and two confirmatory archival analyses are described. Variables related to personality and measures of sleep timing, sleep quality, and sleep duration were initially assessed by self-report in a sample of 54 working adults (31.5% male, 23-48 yrs). Extraversion and neuroticism were measured by the Eysenck Personality Inventory (EPI), and the level of sub-clinical manic-type symptoms by the Attitude to Life Questionnaire (ATLQ). The quality of sleep was measured by the Pittsburgh Sleep Quality Index (PSQI) and by questions relating to habitual sleep latency and minutes awake after sleep onset from the Sleep Timing Questionnaire (STQ). The duration and timing of sleep was assessed using the STQ separately for work-week nights (Sunday-Thursday) and for weekend nights (Friday and Saturday). Morningness-eveningness was assessed using the Composite Scale of Morningness (CSM). Two confirmatory analyses using separate archival samples (Study A: n=201, 55.7% male, 20-57 yrs; Study B: n=101, 47.5% male, 18-59 yrs) were then used to confirm specific correlations of interest. In both initial and confirmatory studies, increased sub-clinical manic-type symptoms were found to be significantly associated with later bedtimes and wake-times during the work-week and lower (more evening-type) CSM scores, and higher neuroticism was associated with poorer sleep as indicated by higher PSQI scores. In contrast, no significant correlations emerged between any of the personality variables and any of the sleep duration variables. Personality appears to affect certain aspects of the timing and subjective quality of sleep, but not necessarily its duration.     

Heritability of morningness-eveningness and self-report sleep measures in a family-based sample of 521 hutterites

Individual variation in the phase and amplitude of human circadian rhythms is well known, but the impact of heritable factors on such variation is less clear. We estimated the narrow-sense heritability for selected circadian and sleep timing, quality, and duration measures among related members of the Hutterites, an endogamous, religious community (n=521 participants). “Morningness-eveningness” (M/E), a stable trait reflecting circadian phase, was evaluated using the Composite Scale (CS). Subjective sleep measures were assessed using the Sleep Timing Questionnaire. Initial analyses reconfirmed the impact of age on M/E. Previously reported correlations between M/E scores and the sleep measures were also noted, demonstrating the construct validity of the questionnaires among the participants. Following corrections for age, gender, and colony of residence, significant narrow-sense heritability was noted for M/E (23%). The heritability for subjective sleep measures (related to timing, duration, and quality) were statistically significant for all but one variable, and varied between 12.4% and 29.4%. Thus, significant heritable influences on human circadian phase and subjective sleep indices can be detected through family-based studies. In view of the impact of circadian malfunction on human health, it may be worthwhile to map genetic factors impacting circadian and sleep variation.     

Sleep, performance, circadian rhythms, and light-dark cycles during two space shuttle flights

Sleep, circadian rhythm, and neurobehavioral performance measures were obtained in five astronauts before, during, and after 16-day or 10-day space missions. In space, scheduled rest-activity cycles were 20-35 min shorter than 24 h. Light-dark cycles were highly variable on the flight deck, and daytime illuminances in other compartments of the spacecraft were very low (5.0-79.4 lx). In space, the amplitude of the body temperature rhythm was reduced and the circadian rhythm of urinary cortisol appeared misaligned relative to the imposed non-24-h sleep-wake schedule. Neurobehavioral performance decrements were observed. Sleep duration, assessed by questionnaires and actigraphy, was only approximately 6.5 h/day. Subjective sleep quality diminished. Polysomnography revealed more wakefulness and less slow-wave sleep during the final third of sleep episodes. Administration of melatonin (0.3 mg) on alternate nights did not improve sleep. After return to earth, rapid eye movement (REM) sleep was markedly increased. Crewmembers on these flights experienced circadian rhythm disturbances, sleep loss, decrements in neurobehavioral performance, and postflight changes in REM sleep.     

Heritability of Morningness‐Eveningness and Self‐Report Sleep Measures in a Family‐Based Sample of 521 Hutterites

Individual variation in the phase and amplitude of human circadian rhythms is well known, but the impact of heritable factors on such variation is less clear. We estimated the narrow‐sense heritability for selected circadian and sleep timing, quality, and duration measures among related members of the Hutterites, an endogamous, religious community (n=521 participants). “Morningness‐eveningness” (M/E), a stable trait reflecting circadian phase, was evaluated using the Composite Scale (CS). Subjective sleep measures were assessed using the Sleep Timing Questionnaire. Initial analyses reconfirmed the impact of age on M/E. Previously reported correlations between M/E scores and the sleep measures were also noted, demonstrating the construct validity of the questionnaires among the participants. Following corrections for age, gender, and colony of residence, significant narrow‐sense heritability was noted for M/E (23%). The heritability for subjective sleep measures (related to timing, duration, and quality) were statistically significant for all but one variable, and varied between 12.4% and 29.4%. Thus, significant heritable influences on human circadian phase and subjective sleep indices can be detected through family‐based studies. In view of the impact of circadian malfunction on human health, it may be worthwhile to map genetic factors impacting circadian and sleep variation.     

Criterion validity of the Pittsburgh Sleep Quality Index: Investigation in a non-clinical sample

The objective of this study was to investigate the reliability and validity of the Pittsburgh Sleep Quality Index (PSQI) in a non-clinical sample consisting of younger and older adults. There has been little research validating the PSQI with respect to multinight recording as with actigraphy, and more validation is needed in samples not specifically selected for clinical disturbance. Also, the degree to which the PSQI scores may reflect depressive symptoms versus actual sleep disturbance remains unclear. One-hundred and twelve volunteers (53 younger and 59 older) were screened for their ability to perform treadmill exercises; inclusion was not based on sleep disturbance or depression. Internal homogeneity was evaluated by correlating PSQI component scores with the global score. Global and component scores were correlated with a sleep diary, actigraphy, and centers for epidemiological studies - depression scale scores to investigate criterion validity. Results showed high internal homogeneity. PSQI global score correlated appreciably with sleep diary variables and the depression scale, but not with any actigraphic sleep variables. These results suggest that the PSQI has good internal homogeneity, but may be less reflective of actual sleep parameters than a negative cognitive viewpoint or pessimistic thinking. The sleep complaints measured may often be more indicative of general dissatisfaction than of any specifically sleep-related disturbance.     

BaSIQS - basic scale on insomnia complaints and quality of sleep: reliability,norms, validity,and accuracy studies,based on clinical and community samples

This research focused on the Basic Scale on Insomnia Symptoms and Quality of Sleep (BaSIQS), formerly validated in undergraduates using the Pittsburgh Sleep Quality Index (PSQI), and aimed to expand internal consistency analysis, examine thoroughly its validity, and determine its clinical accuracy. Considering objective and subjective measures, recruiting non-clinical and clinical samples, this research implemented a comprehensive approach to examine convergent and discriminant validity, confirmatory factor analyses, and the BaSIQS sensitivity and specificity. The BaSIQS was filled out along with the Insomnia Severity Index (ISI), questions on sleep-wake schedules, Composite Scale of Morningness (CSM) and Brief Symptom Inventory-18 (BSI-18) by 1198 adults, 18–64 years old, plus another 30 who wore actimeters, recruited in community settings. A clinical group of 30 chronic insomnia disorder patients also participated. Cronbach alpha coefficient was 0.80. A two-factor structure was confirmed. The association between BaSIQS and ISI was large, whereas actigraphy correlations were medium or small. Medium to non-significant correlations were found concerning conceptually different self-report measures. Comparing the clinic and control groups, the former showed poorer sleep, with a large effect size. Receiver operating characteristic analysis revealed an area under curve = 0.9, and an optimal cut-off score >15. In conclusion, results on reliability, validity, and accuracy provide support to the utility of the BaSIQS both in community and clinical settings, for research and practical purposes.     

Sleep and Circadian Rhythms in Spousally Bereaved Seniors

A laboratory study of sleep and circadian rhythms was undertaken in 28 spousally bereaved seniors (≥60 yrs) at least four months after the loss event. Measures taken included two nights of polysomnography (second night used), ～36 h of continuous core body temperature monitoring, and four assessments of mood and alertness throughout a day. Preceding the laboratory study, two‐week diaries were completed, allowing the assessment of lifestyle regularity using the 17‐item Social Rhythm Metric (SRM) and the timing of sleep using the Pittsburgh Sleep Diary (PghSD). Also completed were questionnaires assessing level of grief (Texas Revised Inventory of Grief [TRIG] and Index of Complicated Grief [ICG]), subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), morningness‐eveningness (Composite Scale of Morningness [CSM]), and clinical interview yielding a Hamilton Depression Rating Scale (HDRS) score. Grief was still present, as indicated by an average TRIG score of about 60. On average, the bereaved seniors habitually slept between ～23:00 and ～06:40 h, achieving ～6 h of sleep with a sleep efficiency of ～80%. They took about 30 min to fall asleep, and had their first REM episode after 75 min. About 20% of their sleep was in Stage REM, and about 3% in Stages 3 or 4 (slow wave sleep). Their mean PSQI score was 6.4. Their circadian temperature rhythms showed the usual classic shape with a trough at ～01:00 h, a fairly steep rise through the morning hours, and a more gradual rise to mid‐evening, with an amplitude of ～0.8°C. In terms of lifestyle regularity, the mean regularity (SRM) score was 3.65 (slightly lower than that usually seen in seniors). Mood and alertness showed time‐of‐day variation with peak alertness in the late morning and peak mood in the afternoon. Correlations between outcome sleep/circadian variables and level of grief (TRIG score) were calculated; there was a slight trend for higher grief to be associated with less time spent asleep (p=0.07) and reduced alertness at 20:00 h (p=0.05). Depression score was not correlated with TRIG score (p>0.20). When subjects were divided into groups by the nature of their late spouse's death (expected/after a long‐term chronic illness [n=18] versus unexpected [n=10]), no differences emerged in any of the variables. In conclusion, when studied at least four months after the loss event, there appears to be some sleep disruption in spousally bereaved seniors. However, this disruption does not appear to be due to bereavement‐related disruptions in the circadian system.     

Construct Validity and Factor Structure of the Pittsburgh Sleep Quality Index and Epworth Sleepiness Scale in a Multi-National Study of African,South East Asian and South American College Students

Background

The Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS) are questionnaires used to assess sleep quality and excessive daytime sleepiness in clinical and population-based studies. The present study aimed to evaluate the construct validity and factor structure of the PSQI and ESS questionnaires among young adults in four countries (Chile, Ethiopia, Peru and Thailand).

Methods

A cross-sectional study was conducted among 8,481 undergraduate students. Students were invited to complete a self-administered questionnaire that collected information about lifestyle, demographic, and sleep characteristics. In each country, the construct validity and factorial structures of PSQI and ESS questionnaires were tested through exploratory and confirmatory factor analyses (EFA and CFA).

Results

The largest component-total correlation coefficient for sleep quality as assessed using PSQI was noted in Chile (r = 0.71) while the smallest component-total correlation coefficient was noted for sleep medication use in Peru (r = 0.28). The largest component-total correlation coefficient for excessive daytime sleepiness as assessed using ESS was found for item 1 (sitting/reading) in Chile (r = 0.65) while the lowest item-total correlation was observed for item 6 (sitting and talking to someone) in Thailand (r = 0.35). Using both EFA and CFA a two-factor model was found for PSQI questionnaire in Chile, Ethiopia and Thailand while a three-factor model was found for Peru. For the ESS questionnaire, we noted two factors for all four countries

Conclusion

Overall, we documented cross-cultural comparability of sleep quality and excessive daytime sleepiness measures using the PSQI and ESS questionnaires among Asian, South American and African young adults. Although both the PSQI and ESS were originally developed as single-factor questionnaires, the results of our EFA and CFA revealed the multi- dimensionality of the scales suggesting limited usefulness of the global PSQI and ESS scores to assess sleep quality and excessive daytime sleepiness.     

A psychometric investigation of the sleep,circadian rhythms,and mood (SCRAM) questionnaire

The sleep, circadian rhythms, and mood (SCRAM) questionnaire (Byrne, Bullock et al., 2017) was designed to concurrently measure individual differences in three clinically important functions: diurnal preference, sleep quality, and mood. The 15-item questionnaire consists of three 5-item scales named Morningness, Good Sleep, and Depressed Mood. The overarching aim of the current project was to investigate the validity and reliability of the questionnaire. Here, we report on associations investigated in three data sets. Study 1 (N = 70, 80% females) was used to examine the test–retest reliability of the questionnaire, finding strong test–retest reliability of the three scales over a 2-week period (r’s ranging from 0.73 to 0.86). Study 2 (N = 183, 80% females) enabled us to examine the construct validity of the SCRAM scales against well-validated self-report measures of diurnal preference, sleep quality, and depression. Strong correlations were found between each SCRAM scale and their respective measure in bivariate analyses, and associations were robust after the inclusion of the remaining two SCRAM scales as predictors in regression analyses. Data from Study 3 (N = 42, 100% males) were used to measure the extent to which SCRAM scores correlated with objective measures of sleep–wake behavior using actigraphy. Morningness was found to be related to earlier sleep onset and offset times, and Good Sleep was related to higher sleep efficiency but to no other measures of sleep quality; Depressed Mood was not related to actigraphy measures. The findings provide provisional support for construct validity and reliability of the SCRAM questionnaire as a measure of diurnal preference, sleep quality, and depressed mood. Future research into the psychometrics of SCRAM should test the questionnaire’s discriminant and predictive validity in clinical samples.     

Associations between chronotype,sleep disturbances and seasonality with fatigue and inflammatory bowel disease symptoms

Growing number of studies suggests link between circadian rhythms and inflammatory bowel diseases (IBD) manifestation. We hypothesize that: 1) IBD are associated with increased eveningness and sleep disturbances; 2) eveningness and sleep disturbances are related to more severe IBD symptoms. In total, 129 participants were enrolled to this study, divided into three groups: 34 Crohn’s disease (CD) patients, 38 ulcerative colitis (UC) patients and 57 healthy controls (HC) group. They all fulfilled a questionnaire, consisting of the Composite Scale of Morningness (CSM), Seasonal Pattern Assessment Questionnaire (SPAQ), Pittsburgh Sleep Quality Index, Inflammatory Bowel Disease Questionnaire (IBDQ) and Multidimensional Fatigue Inventory (MFI). Multiple regression models controlled for age and sex revealed that in CD group higher eveningness measured with CSM was associated with higher general fatigue, physical fatigue, mental fatigue and reduced motivation measured by MFI. Lower CSM morning affect is associated with greater general fatigue, physical fatigue and more reduced activity. Greater seasonality scores are associated with increased physical fatigue and more reduced activity and motivation. Lower sleep quality measured with PSQI is associated with higher physical fatigue and more reduced activity. Correlational analysis revealed that higher seasonality and lower sleep quality are associated with increased systemic and bowel symptoms and decreased emotional and social functions measured with IBDQ. In UC group, eveningness is associated with greater general fatigue, physical fatigue and more reduced activity. Higher CSM morning affect is associated with decreased general fatigue, physical fatigue and less reduced activity. Higher CSM circadian preference scores are associated with decreased general and physical fatigue, and less reduced activity. Increased seasonality is associated with more physical fatigue. Lower sleep quality is associated with greater general and physical fatigue. To our best knowledge this is the first study evaluating associations between chronotype and sleep disturbances with IBD symptoms. We have found that chronotype preferences, whose role in IBD has been until now overlooked, may be one of the important factors contributing to fatigue in this clinical group.     

Variability of Sleep Duration Is Related to Subjective Sleep Quality and Subjective Well-Being: An Actigraphy Study

While there is a large body of evidence that poor subjective sleep quality is related to lower subjective well-being, studies on the relation of objective sleep measures and subjective well-being are fewer in number and less consistent in their findings. Using data of the Survey of Mid-Life in the United States (MIDUS), we investigated whether duration and quality of sleep, assessed by actigraphy, were related to subjective well-being and whether this relationship was mediated by subjective sleep quality. Three hundred and thirteen mainly white American individuals from the general population and 128 urban-dwelling African American individuals between 35 and 85 years of age were studied cross-sectionally. Sleep duration, variability of sleep duration, sleep onset latency, and time awake after sleep onset were assessed by actigraphy over a period of 7 days. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index, positive psychological well-being and symptoms of psychological distress were assessed with the Satisfaction with Life Scale and the Mood and Anxiety Symptom Questionnaire. In both white and African Americans high day-to-day variability in sleep duration was related to lower levels of subjective well-being controlling age, gender, educational and marital status, and BMI. By contrast, sleep duration, sleep onset latency, and time awake after sleep onset were not related to subjective well-being controlling covariates and other sleep variables. Moreover, the relationship between variability in sleep duration and well-being was partially mediated by subjective sleep quality. The findings show that great day-to-day variability in sleep duration – more than average sleep duration – is related to poor subjective sleep quality and poor subjective well-being.     

Gifted and non-gifted students’ diurnal preference and the relationship between personality,sleep, and sleep quality

The current study had two main objectives. First, we examined gifted and non-gifted students’ diurnal preferences. Secondly, we examined the relationships among age, gender, personality, sleep quality, and chronotype of gifted students. Data were gathered from 276 gifted students and 1921 non-gifted students whose ages range between 7 and 17 years old, in same three cities in Turkey using the Composite Scale of Morningness (CSM) to assess diurnal preference, the Big Five Inventory (BIG-5) to assess personality and the Pittsburgh Sleep Quality Index (PSQI) to measure sleep quality. The first result indicated that gifted students were more morning-oriented compared to non-gifted students. The other main result was that the conscientiousness was the best predictor of CSM scores in gifted students. Additionally, conscientiousness, age, and global PSQI predicted CSM scores, respectively. Moreover agreeableness, conscientiousness, and emotional stability were positively related to morning orientation, while age, sleep quality, sleep latency, daytime dysfunction, and global PSQI were negatively related with chronotype in gifted students.     

Stability of melatonin and temperature as circadian phase markers and their relation to sleep times in humans

Circadian rhythms of core body temperature and melatonin are commonly used as phase markers of the circadian clock. Melatonin is a more stable marker of circadian phase when measured under constant routine conditions. However, little is known about the variability of these phase markers under less controlled conditions. Moreover, there is little consensus about the preferred method of analysis. The objective of this study was to assess various methods of calculating melatonin and temperature phase in subjects with regular sleep schedules living in their natural environment. Baseline data were analyzed from 42 healthy young subjects who were studied on at least two occasions. Each hospital admission was separated by at least 3 weeks. Subjects were instructed to maintain a regular sleep schedule, which was monitored for 1 week before admission by sleep logs and actigraphy. Subjects spent one habituation night under controlled conditions prior to collecting baseline temperature and melatonin measurements. The phase of the melatonin rhythm was assessed by 9 different methods. The temperature nadir (Tmin) was estimated using both Cleveland and Cosine curve fitting procedures, with and without demasking. Variability between admissions was assessed by correlation analysis and by the mean absolute difference in timing of the phase estimates. The relationship to sleep times was assessed by correlation of sleep onset or sleep offset with the various phase markers. Melatonin phase markers were more stable and more highly correlated with the timing of sleep than estimates of Tmin. Of the methods for estimating Tmin, simple cosine analysis was the least variable. In addition, sleep offset was more strongly correlated with the various phase markers than sleep onset. The relative measures of melatonin offset had the highest correlation coefficients, the lowest study-to-study variability, and were more strongly associated with sleep timing than melatonin onsets. Concordance of the methods of analysis suggests a tendency for the declining phase of the melatonin profile to be more stable and reliable than either markers of melatonin onset or measures of the termination of melatonin synthesis.     

Sleep and circadian rhythms in spousally bereaved seniors

A laboratory study of sleep and circadian rhythms was undertaken in 28 spousally bereaved seniors (> or =60 yrs) at least four months after the loss event. Measures taken included two nights of polysomnography (second night used), approximately 36 h of continuous core body temperature monitoring, and four assessments of mood and alertness throughout a day. Preceding the laboratory study, two-week diaries were completed, allowing the assessment of lifestyle regularity using the 17-item Social Rhythm Metric (SRM) and the timing of sleep using the Pittsburgh Sleep Diary (PghSD). Also completed were questionnaires assessing level of grief (Texas Revised Inventory of Grief [TRIG] and Index of Complicated Grief [ICG]), subjective sleep quality (Pittsburgh Sleep Quality Index [PSQI]), morningness-eveningness (Composite Scale of Morningness [CSM]), and clinical interview yielding a Hamilton Depression Rating Scale (HDRS) score. Grief was still present, as indicated by an average TRIG score of about 60. On average, the bereaved seniors habitually slept between approximately 23:00 and approximately 06:40 h, achieving approximately 6 h of sleep with a sleep efficiency of approximately 80%. They took about 30 min to fall asleep, and had their first REM episode after 75 min. About 20% of their sleep was in Stage REM, and about 3% in Stages 3 or 4 (slow wave sleep). Their mean PSQI score was 6.4. Their circadian temperature rhythms showed the usual classic shape with a trough at approximately 01:00 h, a fairly steep rise through the morning hours, and a more gradual rise to mid-evening, with an amplitude of approximately 0.8 degrees C. In terms of lifestyle regularity, the mean regularity (SRM) score was 3.65 (slightly lower than that usually seen in seniors). Mood and alertness showed time-of-day variation with peak alertness in the late morning and peak mood in the afternoon. Correlations between outcome sleep/circadian variables and level of grief (TRIG score) were calculated; there was a slight trend for higher grief to be associated with less time spent asleep (p=0.07) and reduced alertness at 20:00 h (p=0.05). Depression score was not correlated with TRIG score (p>0.20). When subjects were divided into groups by the nature of their late spouse's death (expected/after a long-term chronic illness [n=18] versus unexpected [n=10]), no differences emerged in any of the variables. In conclusion, when studied at least four months after the loss event, there appears to be some sleep disruption in spousally bereaved seniors. However, this disruption does not appear to be due to bereavement-related disruptions in the circadian system.