Circadian rhythms and psychiatric disorders in the elderly

This article reviews changes in circadian rhythms that have been reported to occur in the elderly psychiatric population. Data relating to circadian changes in normal aging are included where relevant. Information was obtained from: (1) a computerized MEDLINE search from 1975 to May 1996; (2) a review of bibliographies of papers obtained through the computerized search; and (3) texts on chronobiology. We could not locate any information relating to circadian rhythms and mania, anxiety, or paranoid disorders in old age. Disruption to the sleep/wake cycle, temperature, melatonin, and motor activity rhythms have been reported in dementia and depression, and disruption to some neuroendocrine and cardiovascular rhythms are reported in dementia. Disruption to circadian rhythmicity has implications for the management of dementia patients: for example, the sleep/wake and behavioral disturbances, and for the long-term management of mood disorders. A number of circadian markers have not been studied and several patient groups have received no research attention to date.

The socioeconomic impact of insomnia. An overview

Insomnia is an extremely common symptom both de novo and in the context of other medical and psychiatric disorders. The impact of insomnia is often ignored both by the individual and by society in terms of its clinical and socioeconomic ramifications. Insomnia is therefore under-appreciated and almost certainly under-treated, thus making it a serious health concern. It is estimated that more than 60 million Americans suffer from insomnia annually, and this figure is expected to grow to 100 million by the middle of the 21st century. Whether it be difficulty initiating or maintaining sleep, the disruption of nocturnal sleep will invariably impact on daytime activities and often results in daytime fatigue, performance deficits (including memory and other cognitive deficits), an increase in the number of sick days taken by an individual and accidents (some catastrophic). This review examines the costs directly related to insomnia in various sectors of healthcare, the indirect costs associated with accidents, sick days and decreased work productivity, and related costs resulting from insomnia but which meet neither the criteria of direct nor indirect cost categories. The total direct, indirect and related costs of insomnia are conservatively estimated at $US30 to 35 billion annually in the US (1994 dollars). Economic gains can be made by treating patients on an outpatient basis in sleep centres.

Determination of observer-rated alpha activity during sleep

Patients suffering from chronic fatigue syndrome (CFS) have been described as having alpha intrusion into sleep. In a separate study of the relationship between depression and CFS, we investigated the sleep of CFS patients. We could not detect any observable alpha anomaly in our group of CFS patients. It is possible that there is a subgroup of CFS patients in whom no alpha anomaly is present. However, the sleep electroencephalogram (EEG) montage used in our study was different to that employed by previous researchers. This paper investigates the influence of electrode derivations on the outcome of observable alpha ratings. We compared simultaneous recordings of sleep EEG using three commonly employed montages. Our results indicate that use of the mastoid reference (montage 1) results in the highest observer-related alpha. This may suggest that data regarding alpha intrusion should always be collected using montage 1. However, there is a possibility that the mastoid electrode is not electrically silent and is contaminating the data of the referenced channels. The implications of these findings are discussed in relation to the validity of alpha intrusion measurement of CFS and fibromyalgia.

REM changes in narcolepsy with selegiline

The purpose of this study was to establish the effects of selegiline HCl on sleep parameters in narcolepsy and to contrast these effects with the effects of methylphenidate. Eleven subjects with narcolepsy were studied drug-free and while receiving selegiline (15-30 mg/day) by polysomnography. The methylphenidate-treated group consisted of 11 age-matched subjects with narcolepsy. On overnight polysomnography, compared to pretreatment values, selegiline treatment resulted in a significant increase in rapid eye movement (REM) latency (138.1 +/- 62.8 vs. 48.7 +/- 42.3 minutes, p < 0.05) and sleep stage changes per hour. The increase in REM latency in subjects treated with methylphenidate was marginally significant (116.9 +/- 78.3 vs. 54.3 +/- 23.7 minutes, p = 0.054). Maintenance of wakefulness testing during treatment revealed the methylphenidate-treated group to be significantly more alert than the selegiline-treated group (18.4 +/- 1.9 vs. 9.4 +/- 4.8 minutes, p < 0.001); a retrospective survey of subjects treated with selegiline found that a majority reported clinical improvement with selegiline treatment. These results suggest that selegiline should be considered for further investigation as a treatment for narcolepsy.

Obstructive sleep apnea in a consecutive series of obese women

The prevalence of obstructive sleep apnea (OSA) in women who were being seen for obesity assessment, rather than for assessment of sleep disturbance, was assessed. A consecutive series of referrals to an eating disorders clinic (n = 40) were studied in the sleep laboratory. Their body mass index (BMI) ranged from 29.4 to 66.9 kg/m2. Overnight polysomnograms were carried out, with respiration and oxygen saturation being monitored. Four women (10%), 1 postmenopausal and 3 premenopausal, had significant OSA. They tended to have a higher percentage of body fat and higher BMIs than the nonapnea group. These findings indicate that the prevalence of OSA is higher in the general population of obese women than is generally thought. They highlight the need for professionals who work with obese women to consider the possibility that some of the complaints of fatigue and tiredness may be a result of OSA.

The influence of ipsapirone, a 5-HT1A agonist, on sleep patterns of healthy subjects

Ipsapirone is a new pyrimidinylpiperazine ligand specific for 5-HT1A receptors, with potential therapeutic use in affective disorders. Because 5-HT is involved in the regulation of sleep, we investigated the effect of ipsapirone hydrochloride on sleep patterns in 18 normal, healthy subjects of both sexes. Compared to placebo, ipsapirone 5 mg administered by mouth three times daily for 14 days decreased rapid eye movement (REM) sleep duration and, by the tenth day of treatment, began to reduce slow wave sleep (SWS) duration. The decrease in REM sleep occurred in the first 3 h of sleep. The latency to REM sleep was increased from the first night following ipsapirone administration, remained increased throughout the 14 days of administration, and fell to equal latency on placebo immediately administration ended. Subjective assessments of sleep revealed no differences between ipsapirone and placebo. Our experiments confirm a role of 5-HT1A receptors in sleep. The effects of ipsapirone on the sleep patterns of patients with affective disorders still need to be determined.

Prolonged endurance exercise and sleep disruption

To determine whether exercise duration effects the recovery sleep following exercise, eight fit male endurance athletes, ages 23-42 yr, had their sleep electrophysiologically studied. This was done on four separate occasions: after a day on which no specific exercise was performed; after a day of a 15-km run; after a 42.2-km run day; after a day in which the athletes participated in a strenuous ultra-triathlon. Sleep patterns following the no exercise day and the 15-km and the 42.2-km run days were similar. The sleep pattern of the ultra-triathlon day when compared with the other three days showed significantly increased wakefulness and delayed and decreased rapid eye movement (REM) sleep. The duration of slow wave sleep (SWS) in the first 6 h after lights out, however, was no different. The increased wakefulness and decreased REM clearly indicate increased stress after the ultra-triathlon. REM sleep appears to be a more sensitive index of exercise induced stress than SWS.

Clinical presentation of anorexia nervosa in males: 24 new cases

As part of a larger prognostic study of anorexia nervosa, clinical features at presentation of 24 males with anorexia are described, and compared with a female group matched for date of admission. Data were extracted from the original case records and follow-up interview. The study confirms the view that males display the classical syndrome of anorexia nervosa, but differs from previous studies in several respects. Age at onset (mean 18.6 years) and at presentation (mean 20.2 years) is later, with a mean duration of illness at presentation of only 1.6 years. A premorbid tendency to obesity is confirmed; maximum weight loss during the illness amounted to 42% matched population mean weight (MPMW), and weight at presentation was 78.5% MPMW, somewhat higher than the female group. In keeping with earlier studies, binging and vomiting were noted commonly, in around half of sufferers, but laxative abuse was less frequent and excessive exercising more frequent in males. Depressive and obsessional symptoms are common in both groups, and a strong family history of affective disorders and alcohol abuse was noted in over one third.

Long-term follow-up of patients suffering from obsessive-compulsive disorder treated as in-patients

Few patients with obsessive-compulsive disorder (OCD) require in-patient treatment. There is sparse information on outcome of OCD patients treated as in-patients. This paper is a descriptive account of the current functioning of 54 OCD patients treated in hospital, on average 10 years prior to the study. Follow-up reveals that outcome for the majority of patients is poor with 29 (59%) of the sample showing at least mild symptomatology or some difficulty in several areas of functioning.

Sleep patterns in depression and anxiety: theory and pharmacological effects

Sleep is invariably disrupted in patients who have depression and in patients with anxiety disorders. Depression and anxiety frequently coexist and are associated with disturbances in various neurotransmitters. The authors explore the relationship between sleep and the two disorders as well as the effects of antidepressants and anxiolytics on sleep architecture. The effects on sleep of various neurotransmitter systems implicated in depression and anxiety are outlined. Lastly, various theoretical models are proposed to account for the above mentioned phenomena and further directions for research are suggested.

Is hypersomnolence a feature of seasonal affective disorder?

We examined hypersomnolence as experienced among individuals meeting standardized diagnostic criteria for Seasonal Affective Disorder (SAD). Data were available from 115 individuals attending a mood disorders clinic specializing in treatment of this disorder. Three modes of assessment were employed: retrospective self-reports (Seasonal Patterns Assessment Questionnaire), cross-sectional interviews (Standardized Interview Guide for the Hamilton Depression Scale, SAD Version), and prospective sleep diaries. Results indicated that self-reported total hours of sleep varied significantly across the seasons, with longest sleep occurring in winter and shortest sleep in summer. Seasonal sleep changes, as indicated by the SPAQ did not correlate significantly, however, with severity of depressive symptoms as indicated by the Hamilton scale. Multiple regression analyses indicated that only social activity levels (one of seven SPAQ items) was significantly and uniquely related to the severity of depression. When data obtained by the three instruments were compared, self-reported hours of sleep (whether measured by SPAQ or Hamilton interview) were significantly higher than indicated by prospective sleep diaries. We conclude that hypersomnolence may not be a central feature of SAD and that the validity of the SPAQ as an index of this disorder requires further investigation.

ABC of sleep disorders. Impact and epidemiology of sleep disorders

Images

ABC of sleep disorders. Sleep problems in patients with medical illness

Images

ABC of sleep disorders. Sleep and sleep problems in elderly people

Images

ABC of sleep disorders. Medical problems during sleep

Images

ABC of sleep disorders. Psychotropic drugs and sleep

Images

ABC of sleep disorders. Unexpected presentations of sleep apnoea: use of CPAP in treatment

Images

ABC of sleep disorders. Nocturnal asthma

Images

ABC of sleep disorders. Non-Psychotropic drugs and sleep

Images

ABC of sleep disorder. Dreams and medical illness

Images

ABC of sleep disorders. Parasomnias

Images

Snoring, asthma and sleep disturbance in Britain: a community-based survey

A questionnaire was sent to a random sample of adults in eight locations throughout Britain, to investigate the prevalence of snoring, asthma and sleep complaints in community-based British adult. Of the 1,478 respondents (831 females, 647 males; mean +/- SD age 45 +/- 18 yrs), 37% reported snoring at least occasionally, and 11% reported snoring on at least four nights per week (frequent snorers). Frequent snorers reported spending less time asleep at night, falling asleep accidentally during the day more often, taking planned daytime naps, and falling asleep whilst driving or operating machinery more often than the other respondent. Using ordinal logistic regression analysis to allow for the age and sex of the respondents, both accidental daytime sleep and planned daytime naps were commoner in frequent snorers than other respondents. Six percent of all respondents and 6% of those aged under 40 yrs reported that they had asthma (asthmatics). Seven percent of respondents aged less than 40 yrs reported wheezing on three or more occasions per year, and had been prescribed oral or inhaled bronchodilators (young wheezers). More than 80% of the asthmatic respondents of all ages, and young wheezers, reported waking at night with wheeze at least occasionally, and more than 30% of each group reported this symptom frequently. A larger proportion of asthmatics and young wheezers reported that their night-time sleep was unrefreshing, and that they had too little sleep at night than the other respondents.(ABSTRACT TRUNCATED AT 250 WORDS)

Snoring, asthma and sleep disturbance in Britain: a community-based survey

A questionnaire was sent to a random sample of adults in eight locations throughout Britain, to investigate the prevalence of snoring, asthma and sleep complaints in community-based British adult. Of the 1,478 respondents (831 females, 647 males; mean +/- SD age 45 +/- 18 yrs), 37% reported snoring at least occasionally, and 11% reported snoring on at least four nights per week (frequent snorers). Frequent snorers reported spending less time asleep at night, falling asleep accidentally during the day more often, taking planned daytime naps, and falling asleep whilst driving or operating machinery more often than the other respondent. Using ordinal logistic regression analysis to allow for the age and sex of the respondents, both accidental daytime sleep and planned daytime naps were commoner in frequent snorers than other respondents. Six percent of all respondents and 6% of those aged under 40 yrs reported that they had asthma (asthmatics). Seven percent of respondents aged less than 40 yrs reported wheezing on three or more occasions per year, and had been prescribed oral or inhaled bronchodilators (young wheezers). More than 80% of the asthmatic respondents of all ages, and young wheezers, reported waking at night with wheeze at least occasionally, and more than 30% of each group reported this symptom frequently. A larger proportion of asthmatics and young wheezers reported that their night-time sleep was unrefreshing, and that they had too little sleep at night than the other respondents.(ABSTRACT TRUNCATED AT 250 WORDS)

ABC of sleep disorders. "I don't get enough sleep, doctor"

Images

ABC of sleep disorders. Function of sleep

Images

A group approach for the management of insomnia

To date, the management of insomnia has primarily consisted of pharmacological and behavioral approaches for individual patients. This paper documents the authors' work in formulating a group intervention for patients suffering from insomnia. The treatment rationales are discussed and include group theory, cognitive-behavioral and educational frames of reference. A description of the techniques used and the structure and process of the group model used is provided.

Alleviating sleep-related discontinuance symptoms associated with benzodiazepine withdrawal: a new approach

There is limited information on the time course of recovery of sleep architecture in patients withdrawn from benzodiazepines (BDZ). This study examined the effects of substituting a new class of hypnotic drugs, namely the cyclopyrrolones, for current BDZs in patients presenting with BDZ dependence. The results indicated a clear improvement in a variety of sleep parameters after commencing with a cyclopyrrolone (zopiclone). These changes remained to some extent after zopiclone was discontinued. Also, the absence of certain withdrawal effects (i.e. rebound insomnia) upon discontinuation of zopiclone allows for patients to be carried through a potentially difficult period after stopping BDZs, while expediting the eventual discontinuation of all hypnotic medication.

Restless sleep, illness intrusiveness, and depressive symptoms in three chronic illness conditions: rheumatoid arthritis, end-stage renal disease, and multiple sclerosis

Restless sleep was compared across 110 out-patients with rheumatoid arthritis (RA), 101 with end-stage renal disease (ESRD), 94 with multiple sclerosis (MS), and an unselected control group of 176 individuals attending their family practitioners (FP). It was also investigated in the three chronic illness groups as a contributor to illness intrusiveness--the extent to which one's illness and/or its treatment interfere with continued involvements in valued activities and interests--a determinant of depression and emotional distress in chronic conditions. Reported frequencies of restless sleep were highest in RA, lower in ESRD, and lowest in MS; FP patients reported frequencies that were similar, overall, to those observed in MS. These differences were evident among nondepressed, (chi 2 9, N = 309, p < 0.0001), but not depressed, individuals. The occurrence of restless sleep correlated significantly with increased illness intrusiveness, r (279) = 0.31, p < 0.001, in RA, ESRD, and MS. Results supported the hypothesis that the relation between restless sleep and emotional distress is mediated by illness intrusiveness. Treatment of restless sleep may offer the added benefit of diminishing illness intrusiveness and may, thereby, enhance quality of life in chronic physical illness.

A longitudinal study of sleep stages in young women during pregnancy and postpartum

We conducted a longitudinal polysomnographic study in five healthy primiparous subjects, whose sleep was first recorded between 8 and 16 weeks of gestation, then every 2 months until parturition and at 1 month postpartum. The first 6 hours of sleep were used for statistical analysis. In contrast to previous studies, we found no reduction in stage 4 sleep with pregnancy. Slow-wave sleep (comprising stages 3 and 4), was significantly higher at 27-39 weeks of gestation than at 8-16 weeks, as predicted by the restorative theory of sleep. There was no significant difference in rapid eye movement (REM) sleep time. When compared to a group of normal ovulating women, however, REM sleep time decreased during the last two months of pregnancy and, although there was no change in sleep onset latency, the time spent awake during the first six hours of sleep was increased. Future research into the effects of cortisol and progesterone is indicated.

Seasonality in psychiatry--a review

This paper reviews the literature pertaining to seasonal patterns in psychiatric illnesses. Evidence on the season of birth phenomenon suggests that a greater risk of pre-, peri-, or post-natal damage is associated with the winter months. There is currently insufficient evidence to pinpoint the exact mechanism involved or to ascertain whether the mechanism is common to each condition. Studies of seasonal patterns of incidence of psychiatric disorders have highlighted the role of seasonally regulated environmental factors on internal biological processes. There is growing evidence that serotonin is involved in a variety of psychiatric disorders. Seasonal patterns have been observed in processes involving serotonergic functioning. Furthermore, it has been postulated that these processes may be influenced by photoperiod, suggesting that the seasonal patterns of incidence of several psychiatric conditions may share a common neurophysiological substrate.

Effect of therapeutic theophylline levels on the sleep quality and daytime cognitive performance of normal subjects

The effect of theophylline on sleep quality and cognitive performance in patients with obstructive lung disease has been the subject of controversy. To examine the direct effects of theophylline on sleep quality and cognitive performance, without confounding effects from bronchodilatation, we have undertaken a study of the drug in healthy subjects. A double-blind, placebo-controlled crossover protocol was used to study the effect of oral sustained-release theophylline (Theodur) on subjective sleep quality, objective sleep quality, and cognitive performance. Overnight sleep studies were carried out on Nights 13 and 14 of each 2-wk study limb, and cognitive performance tests administered on Days 1 and 13 of each limb. A total of 18 subjects satisfactorily completed the study (8 males, median age 37, range 24 to 67 yr). Theophylline levels were median 10.2, range 2.3 to 13.3 micrograms/ml on Day 1 and 14.7, range 9.6 to 17.5 micrograms/ml on Day 13. No significant difference was observed between theophylline and placebo on subjective or objective sleep quality or on acute or medium-term cognitive performance. We conclude that theophylline does not affect sleep quality or cognitive performance in normal adults.

Psychiatric morbidity among overseas students

As immigration for higher education is becoming more common now a days, the adjustment of overseas students to the host country is receiving more attention. This paper describes the results of a study which examined the prevalence and pattern of psychological disturbances among overseas and British students studying at Edinburgh University. The practical implications of these findings and suggestions for future research are discussed.

Sleep deprivation and the postnatal blues

This prospective study of 63 women was designed to investigate the relationship between sleep disruption prior to the birth, during labour and in the early postpartum period and the subsequent development of the postnatal blues. The results from this preliminary study suggest that two factors: (a) a night-time labour; and (b) a history of sleep disruption in the latter stages of pregnancy, may have aetiological importance in the development of postnatal blues. There was little evidence from this study to suggest that sleep disruption on the nights following the birth, the third sleep factor investigated, had any impact on the expression of the blues.

Central projections of the sciatic, saphenous, median, and ulnar nerves of the rat demonstrated by transganglionic transport of choleragenoid-HRP (B-HRP) and wheat germ agglutinin-HRP (WGA-HRP)

The central projections of the rat sciatic, saphenous, median, and ulnar nerves were labeled by injecting each nerve with 0.05 mg B-HRP, or 0.5 mg WGA-HRP, or a mixture of both. The B-HRP labeled large dorsal root ganglion cells (30-50 microns) and, correspondingly, 98% of axons labeled in a rootlet were meyelinated; although all sizes of myelinated axons were labeled, a greater proportion fell in the large ranges (2-6.5 microns axon diameter) than in the small ranges (0.5-2 microns). Primary afferents labeled with B-HRP were distributed in laminae I, III, IV, and V of the dorsal horn and extended into the intermediate grey and the ventral horn; Clarke's column and the respective dorsal column nuclei were also densely labeled. Motoneurons of the nerve were densely labeled by B-HRP, including extensive regions of their dendritic trees. In contrast, WGA-HRP labeled small dorsal root ganglion cells (15-25 microns) and in the dorsal rootlets, 84% of the labeled axons were nonmyelinated; the small population of labeled myelinated afferents mainly fell within the smaller ranges (0.5-2.0 microns). Terminal fields of WGA-HRP labeled afferents were restricted to the superficial dorsal horn (laminae I-III), and to limited regions in the dorsal column nuclei. Sciatic nerve projections traced by labeling with B-HRP alone or in combination with WGA-HRP were more extensive than previously described when using either native HRP or WGA-HRP. Afferents to the dorsal horn extended from L1-S1, to Clarke's nucleus from T8-L1, to the ventral horn from L2-L5, and extended throughout the medial and dorsal region of the gracilie nucleus. Motoneurons were found from L4-L6. Using the same tracers, saphenous projections extended in the superficial dorsal horn from caudal L1 to rostral L4, in the deep dorsal horn to mid L4 and along the length of the central part of the gracilie nucleus. The median nerve projected to the internal basilar nucleus from C1-C6, the dorsal horn from C3-T2, Clarke's nucleus from T1-T6, the external cuneate nucleus, and a large central area throughout the length of the cuneate nucleus. Motoneurons were located in dorsolateral and ventrolateral nuclear groups from C4 through C8. The ulnar nerve projections were less extensive but also included the internal basilar nucleus from C1-C6, the medial region of the dorsal horn from C4-T1, Clarke's nucleus from T1-T6, the external cuneate nucleus, and the medial part of the cuneate nucleus.(ABSTRACT TRUNCATED AT 400 WORDS)

Morbidity in nocturnal asthma: sleep quality and daytime cognitive performance

Most patients with asthma waken with nocturnal asthma from time to time. To assess morbidity in patients with nocturnal asthma nocturnal sleep quality, daytime sleepiness, and daytime cognitive performance were measured prospectively in 12 patients with nocturnal asthma (median age 43 years) and 12 age and intellect matched normal subjects. The median (range) percentage overnight fall in peak expiratory flow rate (PEF) was 22 (15 to 50) in the patients with nocturnal asthma and 4 (-4 to 7) in the normal subjects. The patients with asthma had poorer average scores for subjective sleep quality than the normal subjects (median paired difference 1.1 (95% confidence limits 0.1, 2.3)). Objective overnight sleep quality was also worse in the asthmatic patients, who spent more time awake at night (median difference 51 (95% CL 8.1, 74) minutes), had a longer sleep onset latency (12 (10, 30) minutes), and tended to have less stage 4 (deep) sleep (-33 (-58, 4) minutes). Daytime cognitive performance was worse in the patients with nocturnal asthma, who took a longer time to complete the trail making tests (median difference 62 (22, 75) seconds) and achieved a lower score on the paced serial addition tests (-10 (-24, -3)). Mean daytime sleep latency did not differ significantly between the two groups (2 (-3, 7) minutes). It is concluded that hospital outpatients with stable nocturnal asthma have impaired sleep quality and daytime cognitive performance even when having their usual maintenance asthma treatment.

Twenty four hour heart rate variability: effects of posture, sleep, and time of day in healthy controls and comparison with bedside tests of autonomic function in diabetic patients

Heart rate variability was measured in 77 healthy controls and 343 diabetic patients by a count of the number of beat-to-beat differences greater than 50 ms in the RR interval during a 24 hour ambulatory electrocardiogram. In the healthy controls the lower 95% tolerance limits for total 24 hour RR interval counts were approximately 2000 at age 25, 1000 at 45, and 500 at 65 years. Six controls confined to bed after injury had normal 24 hour patterns of RR counts, while eight other controls showed loss of diurnal variation in both heart rate and RR counts during a period of sleep deprivation. RR counts in ten controls on and off night duty increased during sleep whenever it occurred. Nearly half (146) the 343 diabetic patients had abnormal 24 hour RR counts. The percentage of abnormal RR counts increased with increasing autonomic abnormality assessed by a standard battery of tests of cardiovascular autonomic function. A quarter of those with normal cardiovascular reflex tests had abnormal 24 hour RR counts. There were close correlations between 24 hour RR count results and the individual heart rate tests (r = 0.6). The assessment of cardiac parasympathetic activity by 24 hour RR counts was reliable. The diurnal variations in RR counts seen in the controls were probably related to sleep rather than either posture or time of day. The method was more sensitive than conventional tests of cardiovascular reflexes.

Ultrastructural localization of substance P, met-enkephalin, and somatostatin immunoreactivity in lamina X of the primate spinal cord

The ultrastructural localization of substance P (SP), met-enkephalin (MENK), and somatostatin (SS) in the lamina X area surrounding the central canal of the macaque monkey was examined by the indirect peroxidase-antiperoxidase method. The most common synaptic terminals in lamina X were simple terminals (S) with small rounded or pleomorphic clear vesicles; one to two dense-core vesicles were occasionally also present. These were found on soma, dendrites, and dendritic spines, in all regions of lamina X. A second class of terminal with round or oval clear vesicles was glomerular (G) in shape, with scalloped edges, and contained many mitochondria. These large terminals had several synaptic contacts onto dendrites, spines, and small terminals and were found mainly in the lateral region. The third class (L) contained small clear vesicles and several vesicles with large, dense cores (100-125 nm), and also contacted dendrites, mainly lateral to the canal. The fourth class of terminal (D) contained small clear vesicles and several vesicles with small, dense cores (75-100 nm); these contacted dendrites and somata in all areas. Very few terminals with flat vesicles were identified. There was an unequal distribution of immunoreactivity among the several terminal classes identified in lamina X. Most SP terminals were S terminals, but SP L terminals were also common; few were D terminals. MENK terminals were usually either S terminals or D terminals; L terminals were rarely MENK positive. SS terminals were commonly D terminals or S terminals; L terminals were also rarely SS positive. Only SP terminals were identified as G terminals. Synaptic targets of SP, MENK, and SS terminals were most commonly dendrites. In addition to unlabelled neurons, peptidergic neurons and their processes were also synaptic targets of terminals containing the same peptide. The distributions of these peptides in primate lamina X differ from that of the same peptides in primate superficial dorsal horn. These differences are important, in consideration of some of the parallels that may be drawn between the lamina X area and the superficial dorsal horn; both areas have high concentrations of the same peptides, receive nociceptive primary afferents, and contain spinothalamic and other projection neurons. Nevertheless, comparison of the distribution of immunoreactivity among terminal classes indicates that neurochemical organization at the ultrastructural level is quite distinct in each of the two areas. This may also reflect other roles of the lamina X area, including its involvement in visceral functions, although it would be expected that this element might be less prominent at the cervical levels we investigated.

Evaluation of bioelectrical impedance analysis for body composition measurements in anorexia nervosa

Many established methods of measuring body composition are time consuming and require complex equipment which is not generally available. Bioelectrical impedance analysis is a technique which utilises the difference in conductivity between fat and lean tissues at radiofrequencies. It uses inexpensive equipment which is simple to use and does not involve the use of ionising radiation. We have evaluated this technique in 44 studies on 38 anorexic females with a wide range of body mass index. Fat free mass was obtained from the mean of three established methods. The initial calibration was derived from 21 studies on 19 anorexics. Fat free mass was regressed against impedance and body habitus parameters to establish the prediction equation with the smallest standard error (1.12 kg). Values of fat free mass derived using this prediction equation were then compared with the other methods in a prospective study. The error of the bioelectrical impedance technique compares favourably with the established methods, even in anorexic patients with very low body mass index.

Daylight saving time in psychiatric illness

It has been reported that the change in photoperiod induced by the occurrence of daylight saving time has an effect on psychiatric presentation. We therefore investigated the impact of daylight saving time in three conditions: (1) parasuicide presentations; (2) psychiatric outpatient contacts, and inpatient admissions; (3) registered suicides. Results indicate that neither the change in photoperiod nor the effect of a small change in circadian rhythm associated with daylight saving time has an effect on 'cases' in any of the three conditions.

Ventilatory and arousal responses to added inspiratory resistance during sleep

Airway resistance increases during sleep. We have determined the ventilatory and arousal responses to the addition of inspiratory resistance of 4, 7, or 10 cmH2O/L/s during sleep in 10 normal men who slept wearing valved face masks. Insufficient ventilatory response data were obtained during rapid eye movement (REM) sleep to allow adequate analysis. The immediate responses to loading were decreases in tidal volume (VT), breathing frequency (f), and minute ventilation (VE), with no difference between wakefulness and Stage 2 and Stage 3/4 sleep in the effects of loading on VT and VE, but f fell more during wakefulness than during sleep (p less than 0.05) because of a greater lengthening of inspired time (TI) (p less than 0.05). During the first 10 breaths, occlusion pressure (P0.1) increased similarly in all EEG stages. Averaging responses during the 2-min periods when resistances were applied, the only variable to differ between EEG stages was TI, which increased more in wakefulness than in Stage 2 or Stage 3/4 sleep (p less than 0.01). Arousal within 2 min of application of resistance occurred less frequently from Stage 3/4 sleep than from Stage 2 or REM sleep (p less than 0.02). The study demonstrates that sleep modifies the changes in respiratory timing produced by resistive loading without having a major effect on ventilation or P0.1 responses. The low frequency of arousal from Stage 3/4 sleep with loading may explain why asthmatics rarely awaken from this stage with wheeze.