Sleep disorders in a naturalistic cohort of Dutch psychiatric outpatients: prevalence rates and associations with psychopathology symptom severity and well-being

Sleep problems are very common in individuals with a mental disorder. Given the abundant evidence indicating the negative impact of disturbed sleep on mental health outcome, insight into the prevalence of all types of sleep disorders in specific mental disorders and neurodevelopmental conditions is of practical importance. Therefore, we estimated the prevalence of six types of sleep disorders with the Holland Sleep Disorders Questionnaire in an overall mental health sample (n = 1082) and separately for different mental and neurodevelopmental conditions. Furthermore, associations between specific sleep disorders, psychopathology and well-being were studied. The impact of the total number of sleep disorders on these associations was examined. Overall, 46.2% of all participants scored above the cut-off for having a sleep disorder. Specifically, 26.8% scored on insomnia, 12.1% on sleep breathing disorders, 9.7% on hypersomnia, 13.7% on circadian rhythm sleep-wake disorders, 11.2% on parasomnia, and 17.9% on sleep-related movement disorders. Most sleep disorders were associated with greater severity of psychopathology and lower well-being. These associations got stronger with an increasing number of sleep disorders. Our study revealed higher suspected prevalence of most sleep disorders in a mental disorder sample compared to the general population. Moreover, the presence of sleep disorder(s) was strongly associated with symptom severity and reduced well-being. These findings extend the notion that early detection and treatment of sleep disorders in mental health populations is essential for psychiatric outcome.

Trajectories of insomnia following bereavement

BACKGROUND

Insomnia symptoms are common following bereavement and may exacerbate severe and protracted grief reactions, such as prolonged grief disorder (PGD). However, typical trajectories of insomnia symptoms and risk factors for having a more chronic insomnia trajectory following bereavement are yet unknown.

METHOD

In the current investigation, 220 recently bereaved (≤6 months post-loss) participants, completed questionnaires assessing sociodemographic and loss-related characteristics, rumination, experiential avoidance and symptoms of (prolonged) grief and depression, on three time-points (6 months apart). We applied growth mixture models to investigate the typical trajectories of insomnia symptoms following bereavement.

RESULTS

Three insomnia trajectory classes emerged, characterized by a resilient (47 %), recovering (43 %), and a chronic trajectory (10 %). Baseline depression symptoms best predicted the type of insomnia trajectory. At one-year follow-up, 9 %, 27 %, and 60 % of participants met the criteria for probable PGD within the resilient, recovering and chronic trajectory, respectively. A parallel process model showed that temporal changes in insomnia symptoms were strongly related to changes in prolonged grief symptoms.

CONCLUSION

The results suggest, that targeting insomnia symptoms in the treatment of PGD, particularly with comorbid depression, may be a viable option.

Shift work is associated with extensively disordered sleep, especially when working nights

Background

Shift work is generally associated with working and sleeping out of phase with the endogenous, circadian sleep-wake cycle. This exerts detrimental effects on sleep health. The present study aimed at evaluating the presence of short and long sleep as well as sleep disorders within a broad range of shift work schedules and elucidating the role of sociodemographic factors therein.

Methods

A large dataset containing information on sleep was collected through advertisement in a Belgium newspaper (De Standaard). Adult, working individuals were selected (n = 37,662) and categorized based on their work schedule (regular day, early morning, evening, night, and rotating shift). In this cross-sectional study, prevalence rates of short sleep (≤6 h), long sleep (≥9 h) and sleep disorders (screened with Holland Sleep Disorders Questionnaire), and associations between these sleep variables and sociodemographics (age, sex, education, living companion(s)) were analyzed using binominal logistic regression analyses.

Results

In the total sample all sociodemographic factors affected prevalences of short, long and disordered sleep, consistent with previous studies. Compared to day workers, shift workers more frequently reported short sleep, most prominently night workers (26 vs. 50%) (p < 0.001). Furthermore, all sleep disorders as well as sleep disorder comorbidity were more common in shift workers, again most pronounced in night workers (all p < 0.05). In night shift workers the level of education had the strongest associations with disturbed sleep with a two-fold higher prevalence of short and disordered sleep in low relative to academic educated groups (all p < 0.02).

Conclusion

Shift work is related not only to curtailed sleep and shift work disorder, but also to a plethora of sleep disorders, including insomnia, sleep-related breathing disorders and sleep-related movement disorders. Our findings imply that education on coping strategies may be especially important for young and/or lower educated shift workers.

The influence of sexual activity on sleep: A diary study

Aiming to promote overall health and well-being through sleep, the present studies examine to what extent sexual activity serves as a behavioural mechanism to improve sleep. The relation between sexual activity, i.e., partnered sex and masturbation with or without orgasm, and subjective sleep latency and sleep quality is examined by means of a cross-sectional and a longitudinal (diary) study. Two hundred fifty-six male and female participants, mainly students, completed a pre-test set of questionnaires and, thereafter, a diary during 14 consecutive days. The cross-sectional study was analysed using analysis of covariance and demonstrated that both men and women perceive partnered sex and masturbation with orgasm to improve sleep latency and sleep quality, while sexual activity without orgasm is perceived to exert negative effects on these sleep parameters, most strongly by men. Accounting for the repeated measurements being nested within participants, the diary data were analysed using multilevel linear modelling (MLM). Separate models for subjective sleep latency and sleep quality were constructed, which included 2076 cases at level 1, nested within 159 participants at level 2. The analyses revealed that only partnered sex with orgasm was associated with a significantly reduced sleep latency (b = -0.08, p < 0.002) and increased sleep quality (b = 0.19, p < 0.046). Sexual activity without orgasm and masturbation with and without orgasm were not associated with changes in sleep. Further, no gender differences emerged. The present studies confirm and significantly substantiate findings indicating that sexual activity and intimacy may improve sleep and overall well-being in both men and women and serve as a directive for future research.

Schema therapy for violent PD offenders: a randomized clinical trial

BACKGROUND

Violent criminal offenders with personality disorders (PD's) can cause immense harm, but are often deemed untreatable. This study aimed to conduct a randomized clinical trial to test the effectiveness of long-term psychotherapy for rehabilitating offenders with PDs.

METHODS

We compared schema therapy (ST), an evidence-based psychotherapy for PDs, to treatment-as-usual (TAU) at eight high-security forensic hospitals in the Netherlands. Patients in both conditions received multiple treatment modalities and differed only in the individual, study-specific therapy they received. One-hundred-three male offenders with antisocial, narcissistic, borderline, or paranoid PDs, or Cluster B PD-not-otherwise-specified, were assigned to 3 years of ST or TAU and assessed every 6 months. Primary outcomes were rehabilitation, involving gradual reintegration into the community, and PD symptoms.

RESULTS

Patients in both conditions showed moderate to large improvements in outcomes. ST was superior to TAU on both primary outcomes - rehabilitation (i.e. attaining supervised and unsupervised leave) and PD symptoms - and six of nine secondary outcomes, with small to moderate advantages over TAU. ST patients moved more rapidly through rehabilitation (supervised leave, treatment*time: F(5308) = 9.40, p < 0.001; unsupervised leave, treatment*time: F(5472) = 3.45, p = 0.004), and showed faster improvements on PD scales (treatment*time: t(1387) = -2.85, p = 0.005).

CONCLUSIONS

These findings contradict pessimistic views on the treatability of violent offenders with PDs, and support the effectiveness of long-term psychotherapy for rehabilitating these patients, facilitating their re-entry into the community.

Cross-Lagged Analyses of Prolonged Grief and Depression Symptoms with Insomnia Symptoms

Prolonged grief disorder, characterized by severe, persistent and disabling grief, has recently been added to the DSM-5-TR and ICD-11. Treatment for prolonged grief symptoms shows limited effectiveness. It has been suggested that prolonged grief symptoms exacerbate insomnia symptoms, whereas insomnia symptoms, in turn, may fuel prolonged grief symptoms. To help clarify if treating sleep disturbances may be a viable treatment option for prolonged grief disorder, we examined the proposed reciprocal relationship between symptoms of prolonged grief and insomnia. On three time points across 6-month intervals, 343 bereaved adults (88% female) completed questionnaires to assess prolonged grief, depression, and insomnia symptoms. We applied random intercept cross-lagged panel models (RICLPMs) to assess reciprocal within-person effects between prolonged grief and insomnia symptoms and, as a secondary aim, between depression and insomnia symptoms. Changes in insomnia symptoms predicted changes in prolonged grief symptoms but not vice versa. Additionally, changes in depression and insomnia symptoms showed a reciprocal relationship. Our results suggest that targeting insomnia symptoms after bereavement is a viable option for improving current treatments for prolonged grief disorder.

Effectivity of (Personalized) Cognitive Behavioral Therapy for Insomnia in Mental Health Populations and the Elderly: An Overview

Insomnia is very prevalent in psychiatry and is considered a transdiagnostic symptom of mental disorders. Yet, it is not only a consequence of a mental condition but may also exert detrimental effects on psychiatric symptom severity and therapeutic response; thus, adequate insomnia treatment is particularly important in psychiatric populations. The first choice of intervention is cognitive behavioral therapy for insomnia (CBT-I) as it is rather effective, also in the long run without side effects. It is offered in various forms, ranging from in-person therapy to internet-delivered applications. CBT-I protocols are typically developed for individuals with insomnia disorder without co-occurring conditions. For an optimal therapeutic outcome of CBT-I in individuals with comorbid mental disorders, adaptations of the protocol to tailor the treatment might be beneficial. Based on a literature search using major search engines (Embase; Medline; APA Psych Info; and Cochrane Reviews), this paper provides an overview of the effectiveness of the different CBT-I applications in individuals with diverse comorbid mental conditions and older adults and describes the functionality of CBT-I protocols that have been personalized to specific psychiatric populations, such as depression, substance abuse, and schizophrenia spectrum disorder. Finally, we discuss urgent needs for insomnia therapy targeted to improve both sleep and psychopathologies.

Disturbed Sleep in PTSD: Thinking Beyond Nightmares

Sleep disturbances frequently co-occur with posttraumatic stress disorder (PTSD). Insomnia and nightmares are viewed as core symptoms of PTSD. Yet, relations between disturbed sleep and PTSD are far more complex: PTSD is linked to a broad range of sleep disorders and disturbed sleep markedly affects PTSD-outcome. This article provides a concise overview of the literature on prevalent comorbid sleep disorders, their reciprocal relation with PTSD and possible underlying neurophysiological mechanisms. Furthermore, diagnostic procedures, standard interventions-particularly first choice non-pharmacological therapies-and practical problems that often arise in the assessment and treatment of sleep disturbances in PTSD are described. Finally, we will present some perspectives on future multidisciplinary clinical and experimental research to develop new, more effective sleep therapies to improve both sleep and PTSD.

The clinical relevance of early identification and treatment of sleep disorders in mental health care: protocol of a randomized control trial

BACKGROUND

Sleep disorders are a risk factor for developing a variety of mental disorders, have a negative impact on their remission rates and increase the risk of relapse. Early identification and treatment of sleep disorders is therefore of paramount importance. Unfortunately, in mental health care sleep disorders are often poorly recognized and specific treatment frequently occurs late or not at all. This protocol-paper presents a randomized controlled trial investigating the clinical relevance of early detection and treatment of sleep disorders in mental health care. The two aims of this project are 1) to determine the prevalence of sleep disorders in different mental disorders, and 2) to investigate the contribution of early identification and adequate treatment of sleep disorders in individuals with mental disorders to their sleep, mental disorder symptoms, general functioning, and quality of life.

METHODS

Patients newly referred to a Dutch mental health institute for psychiatric treatment will be screened for sleep disorders with the self-assessment Holland Sleep Disorders Questionnaire (HSDQ). Patients scoring above the cut-off criteria will be invited for additional diagnostic evaluation and, treatment of the respective sleep disorder. Participants will be randomly assigned to two groups: Immediate sleep diagnostics and intervention (TAU+SI-T0), or delayed start of sleep intervention (TAU+SI-T1; 6 months after inclusion). The effect of sleep treatment as add-on to treatment as usual (TAU) will be tested with regard to sleep disorder symptoms, general functioning, and quality of life (in collaboration with a psychiatric sleep centre).

DISCUSSION

This trial will examine the prevalence of different sleep disorders in a broad range of mental disorders, providing information on the co-occurrence of specific sleep and mental disorders. Further, this study is the first to investigate the impact of early treatment of sleep disorders on the outcome of many mental disorders. Moreover, standard sleep interventions will be tailored to specific mental disorders, to increase their efficacy. The results of this trial may contribute considerably to the improvement of mental health care.

TRIAL REGISTRATION

This clinical trial has been retrospectively registered in the Netherlands Trial Register (NL8389; https://www.trialregister.nl/trial/8389) on February 2th, 2020.

Sleep disturbances in bereavement: A systematic review

Severe, persistent and disabling grief occurs among a sizable minority experiencing bereavement, with diagnostic manuals newly including complicated grief (CG) disorders. Sleep disturbances/disorders have been established as worsening affective and stress-related conditions. However, the role of sleep difficulties in bereavement and CG has not received similar scientific attention. We therefore conducted a systematic review with narrative syntheses on this topic to clarify the role of sleep in bereavement (PROSPERO: CRD42018093145). We searched PubMed, Web of Science and PsychInfo for peer-reviewed English-language articles including (at least one) bereaved sample and sleep disturbance measure. We identified 85 articles on 12.294 participants. We answered seven pre-defined research questions demonstrating: high prevalence of sleep disturbances in bereavement; positive associations of grief intensity with sleep difficulties; preliminary indications of risk factors of post-loss sleep disturbance; higher prevalence of sleep disturbances in CG, enhanced by psychiatric comorbidity (i.e., depression); and initial evidence of causal relationships between (complicated) grief and sleep. Grief therapy partly improves sleep difficulties, yet no intervention studies have specifically targeted sleep problems in bereaved persons. Causal relationships between sleep and grief require further examination in intensive longitudinal investigations, including randomized trials, thereby clarifying whether treating sleep problems enhances CG treatment effects.

[Sleep: the basis of a healthy lifestyle]

The use of sleep as modifiable lifestyle factor is not yet self-evident in psychiatry.<br/> AIM: To increase knowledge about sleep as health-affecting factor.<br/> METHOD: Description of normal sleep, effects of disturbed sleep and lifestyle advice to promote healthy sleep.<br/> RESULTS: Disturbed sleep negatively impacts physical and mental health. Targeted lifestyle advice can improve sleep and bring about positive effects in multiple areas.<br/> CONCLUSION: From preventive and treatment perspectives, interventions optimizing sleep in psychiatric care seem promising.

[Intoxicated women: A study into gender differences in substance abuse in forensic psychiatric patients]

Substance abuse is an important risk factor for (violent) offending, but is mostly studied in male populations. More knowledge about women is needed.<br/> AIM: To gain insight into possible gender differences in substance abuse and offending in forensic psychiatric patients.<br/> METHOD: Files were analysed of 275 women and 275 men who have been admitted between 1984 and 2014 to one of four Dutch forensic psychiatric facilities and related to incidents of violence during treatment or recidivism after discharge (for 78 women).<br/> RESULTS: Although substance abuse was common in women (57%), it was significantly more prevalent in men (68%). Men were more often diagnosed with substance dependency and more often committed the index-offense whilst intoxicated. Predictive accuracy for violent incidents during treatment was better for men. Both women and men with substance abuse had significantly more historical risk factors compared to those without substance abuse. A history of substance abuse was not a significant predictor for recidivism after discharge in women.<br/> CONCLUSION: There are gender differences in substance abuse and the relationship with offending was stronger for men. These differences may have implications for substance use treatment in forensic mental health services.

Patient-rated impulsivity and aggression compared with clinician-rated risk in a forensic psychiatric sample: Predicting inpatient incidents

BACKGROUND

Measures of impulsivity and aggression help to indicate risk of future violence or rule-breaking. Both clinician-rated risk assessment and self-report measures have been used but hardly ever compared in their ability to predict inpatient incidents.

AIMS

To compare the self-report on the Barratt Impulsiveness Scale (BIS-11) and Buss-Perry Aggression Questionnaire (BPAQ) with the clinician-rated HKT-30, a Dutch adaptation of the Historical Clinical Risk Management-20, for their capacity to predict inpatient incidents.

METHODS

All men newly admitted to a forensic psychiatric hospital were invited to participate in this study unless in intensive care. Tests of correlation were run between the BIS-11 and BPAQ scale scores and the HKT-30. Each was then tested separately for capacity to predict the number of aggressive and nonaggressive incidents while resident. Finally, scores of all rating scales were entered together into a negative binomial regression to compare their relative strengths in predicting later incidents.

RESULTS

Patient and staff baseline impulsivity and aggression ratings correlated moderately well. All measures performed well in univariate analyses of relationship between baseline measures and later incidents. In final models, which included both patient and staff baseline ratings, the HKT-30 generally outperformed the self-report measures in the prediction of aggressive and nonaggressive incidents in both the first year and total length of stay.

IMPLICATIONS FOR CLINICAL PRACTICE

Our findings suggest that some reliance may be placed on patient ratings of their own propensity for impulsive and/or violent acts, but, when used, they should remain combined with clinician-rated risk assessment for the time being. Future research should explore their utility in dialogue about treatment, and also the relative strength of staff response to each.

Poor sleep quality at baseline is associated with increased aggression over one year in forensic psychiatric patients

OBJECTIVE

In forensic psychiatric patients, sleep problems as well as impulsivity and aggression are highly prevalent, yet studies on their association over time are lacking. This study investigates the association between sleep quality and changes in impulsivity and aggression in forensic psychiatric patients over one year.

METHODS

Data were drawn from an ongoing prospective observational study in adult forensic psychiatric patients admitted to a forensic treatment facility between October 2006 and January 2018. Validated self-reports and observational instruments were used to assess sleep quality, impulsivity and aggression upon admission to the hospital and after one year. Linear regression analyses were performed to examine the association between sleep quality, impulsivity and aggression. All models were adjusted for baseline values of outcome measures, demographic features and general psychopathology.

RESULTS

Data from 83 men (age 37.7 ± 11.7 years) with completed consecutive measurements were analyzed. Poor sleep quality was associated with increased self-reported aggression (β = 1.08; 95% CI, 0.38-1.78). This association was positively confounded by general psychopathology, indicating that sleep quality is specifically related to self-reported aggression instead of being part of general psychopathology (adjusted β = 1.18; 95% CI, 0.39-1.97). Poor sleep quality was not associated with changes in self-reported impulsivity, clinician-rated impulsivity or clinician-rated hostility in this population.

CONCLUSION

Poor sleep quality was associated with an increase in self-reported aggression over one year in male forensic psychiatric patients. Early evaluation and treatment of sleep problems in (forensic) psychiatric patients may play an important role in reducing the risk of aggressive behavior.

Poor Sleep and Its Relation to Impulsivity in Patients with Antisocial or Borderline Personality Disorders

Studies investigating sleep and personality disorders consistently demonstrate a relation between personality disorders characterized by behavioral disinhibition and/or emotional dysregulation (traditionally termed cluster B personality disorders) and poor sleep. This finding is in line with previous studies associating insomnia with impulsive behavior, since this is a core characteristic of both antisocial and borderline personality disorder. The current study investigates a group (n = 112) of forensic psychiatric inpatients with antisocial or borderline personality disorder or traits thereof. Subjective sleep characteristics and impulsivity were assessed with the Pittsburgh Sleep Quality Index, the Sleep Diagnosis List, and the Barratt Impulsiveness Scale, respectively. More than half of the patients (53.6%) report poor sleep quality and 22.3% appears to suffer from severe chronic insomnia. Both poor sleep quality and chronic insomnia are significantly associated with self-reported impulsivity, in particular with attentional impulsiveness. This association was not significantly influenced by comorbid disorders. Actively treating sleep problems in these patients may not only improve sleep quality, mental health, and physical well-being, but may also have impact on impulsivity-related health risks by increasing self-control.

Low doses of mirtazapine or quetiapine for transient insomnia: A randomised, double-blind, cross-over, placebo-controlled trial

Low doses of the antidepressant mirtazapine or the neuroleptic quetiapine are often prescribed off-label for insomnia. However, studies on the effects on sleep and hangover effects the following day are scarce. In this randomised, double-blind, cross-over, placebo-controlled trial, the influence of 7.5 mg mirtazapine and 50 mg quetiapine on both normal sleep and sleep disturbed by acoustic stress (traffic noise) as a model for transient insomnia was assessed. Additionally, hangover effects on next-day alertness and cognitive functioning were examined. A total of 19 healthy men without sleep complaints completed three treatment sessions, each session consisting of three consecutive nights in one of the mirtazapine, quetiapine or placebo conditions. Sleep was assessed using polysomnography and the Leeds Sleep Evaluation Questionnaire. Daytime sleepiness and cognitive functioning were assessed using the Leeds Sleep Evaluation Questionnaire, Karolinska Sleepiness Scale, Digit Symbol Substitution Task, Psychomotor Vigilance Task and an addition task. Under acoustic stress, both mirtazapine and quetiapine increased total sleep time by half an hour and reduced the number of awakenings by 35-40% compared to placebo. While quetiapine specifically increased the duration of non-rapid eye movement sleep, stage N2, mirtazapine mainly increased deep sleep stage N3. Subjects reported that both mirtazapine and quetiapine eased getting to sleep and improved sleep quality. Both drugs caused daytime sleepiness and lessened sustained attention. These findings support the use of low doses of mirtazapine and quetiapine for the treatment of insomnia. Further prospective studies on the long-term effects regarding effectiveness and adverse effects are needed.

Specific risk factors of arsonists in a forensic psychiatric hospital

Arsonists are often treated in forensic settings. However, high recidivism rates indicate that treatment is not yet optimal for these offenders. The aim of this case series study is to identify arsonist specific dynamic risk factors that can be targeted during treatment. For this study, we used patient files of and interviews with all patients that were currently housed at a forensic psychiatric hospital in the Netherlands (14 arsonists, 59 non-arsonists). To delineate differences in risk factors between arsonists and non-arsonists, scores on the risk assessment instrument the Historical Clinical Future-30 (HKT-30; completed for 11 arsonists and 35 non-arsonists), an instrument similar to the Historical Clinical Risk Management-20 (HCR-20), were compared. The groups did not differ on demographic factors and psychopathology. Concerning dynamic risk factors, arsonists had significantly poorer social and relational skills and were more hostile. Although this study needs replication, these findings suggest that the treatment of people involved in firesetting should particularly target these risk factors.

[Violent women: a multicentre study of the characteristics of female forensic psychiatric patients]

BACKGROUND

Violence perpetrated by women has attracted more and more attention in the past few years. However, there is lack of background information about women admitted to forensic psychiatric hospitals and about risk factors for recidivism.

AIM

To conduct a multicenter study which will give more insight into female psychiatric patients and which will probably have implications for psychodiagnostics, risk assessment and treatment in (forensic) psychiatric settings.

METHOD

We coded the files of 297 women who, between 1984 and 2013, had been admitted to one of four Dutch forensic psychiatric facilities by reason of violent delinquent behaviour. We used an extensive coding list and several risk assessment tools including the recently developed Female Additional Manual (fam) for women.

RESULTS

The general picture that emerged was one of severely traumatised women with complex pathology and a high level of comorbidity. Many of the women had experienced previous treatment failures and had caused many incidents during treatment.

CONCLUSION

Female forensic psychiatric patients are a complex group that deserves more specific attention. Attention for traumas from the past, intensive supervision in relationships and training for staff in dealing with, for instance, manipulative behaviour are the most important implications from this study.

Sleep disturbances in a clinical forensic psychiatric population

OBJECTIVE

Poor sleep is known to cause detrimental effects on the course of diverse psychiatric disorders and is a putative risk factor for hostility and aggression. Thus, sleep may be crucial in forensic psychiatric practice. However, little is known about the prevalence of sleep disturbances in these complex psychiatric patients.

METHODS

In this study we investigated the presence of sleep disorders and subjective sleep quality using the Sleep Diagnosis List (SDL), the Pittsburgh Sleep Quality Index (PSQI), interviews addressing the causes of sleep complaints, and file information on sleep medications in 110 patients admitted to a forensic psychiatric hospital.

RESULTS

Almost 30% of the participants suffered from one or more sleep disorders, especially insomnia. An even larger proportion of the participants (49.1%) experienced poor sleep quality. Interestingly, patients with an antisocial personality disorder or traits were particularly dissatisfied with their sleep. The most common causes of sleep problems were suboptimal sleep hygiene, stress or ruminating, negative sleep conditioning, and side effects of psychotropic medication. Of the poor sleepers, 40.7% received a hypnotic drug.

CONCLUSION

Despite intensive clinical treatment, sleep problems are experienced by a large number of forensic psychiatric patients. It would be worthwhile to examine the effects of pharmacological and non-pharmacological sleep interventions on both psychiatric symptoms and reactive aggressive behavior in forensic patients.

A review of modafinil and armodafinil as add-on therapy in antipsychotic-treated patients with schizophrenia

Schizophrenia is characterized by reality distortion, psychomotor poverty and cognitive disturbances. These characteristics contribute to a lesser social functioning and lower quality of life in patients with schizophrenia. It has been suggested that modafinil and its isomer armodafinil as an add-on strategy to antipsychotic treatment in patients with schizophrenia may improve cognitive functioning, attenuate fatigue, inactiveness and other negative functions as well as weight gain. In this paper we review the literature relevant to the question of whether modafinil and armodafinil are beneficial as add-on therapy in antipsychotic-treated patients with schizophrenia. A total of 15 articles were included in this review; of the 15 articles, 10 were randomized controlled trials (RCTs). Evidence for the use of modafinil or armodafinil as add-on therapy to antipsychotic drugs to alleviate fatigue, sleepiness and inactivity is inconclusive. One cohort study and one out of two single-dose crossover RCTs in which modafinil addition was studied could demonstrate a positive effect. All five RCTs of modafinil (three RCTs) and armodafinil (two RCTs) addition with a longer study duration could not demonstrate a positive effect. With respect to cognitive disturbances, animal models of cognitive deficits show clear improvements with modafinil. In RCTs with a treatment duration of 4 weeks or more, however, no positive effect could be demonstrated on cognitive functioning with modafinil and armodafinil addition. Yet, four single-dose crossover RCTs of modafinil addition show significant positive effects on executive functioning, verbal memory span, visual memory, working memory, spatial planning, slowing in latency, impulse control and recognition of faces expressing sadness and sadness misattribution in the context of disgust recognition. The addition of modafinil or armodafinil to an antipsychotic regime, despite theoretical and preclinical considerations, has not been proved to enhance cognitive function, attenuate fatigue, enhance activity, improve negative symptoms and reduce weight in patients with schizophrenia.

Poor sleep as a potential causal factor in aggression and violence

Clinical observations suggest that sleep problems may be a causal factor in the development of reactive aggression and violence. In this review we give an overview of existing literature on the relation between poor sleep and aggression, irritability, and hostility. Correlational studies are supporting such a relationship. Although limited in number, some studies suggest that treatment of sleep disturbances reduces aggressiveness and problematic behavior. In line with this is the finding that sleep deprivation actually increases aggressive behavior in animals and angriness, short-temperedness, and the outward expression of aggressive impulses in humans. In most people poor sleep will not evoke actual physical aggression, but certain individuals, such as forensic psychiatric patients, may be particularly vulnerable to the emotional dysregulating effects of sleep disturbances. The relation between sleep problems and aggression may be mediated by the negative effect of sleep loss on prefrontal cortical functioning. This most likely contributes to loss of control over emotions, including loss of the regulation of aggressive impulses to context-appropriate behavior. Other potential contributing mechanisms connecting sleep problems to aggression and violence are most likely found within the central serotonergic and the hypothalamic-pituitary-adrenal-axis. Individual variation within these neurobiological systems may be responsible for amplified aggressive responses induced by sleep loss in certain individuals. It is of great importance to identify the individuals at risk, since recognition and adequate treatment of their sleep problems may reduce aggressive and violent incidents.

Elevated estradiol plasma levels in women with restless legs during pregnancy

STUDY OBJECTIVES

Pregnant women have an increased risk of experiencing restless legs syndrome (RLS). Aim of this study was to elucidate the relationship between pregnancy-related hormonal and metabolic changes and RLS symptomatology.

DESIGN

Blood measurements and overnight polysomnography were performed during the third trimester of pregnancy and again 3 months after delivery. We investigated blood hormonal levels (estradiol, prolactin, progesterone, testosterone, follicle-stimulating hormone [FSH], luteinizing hormone [LH], iron, ferritin, hemoglobin) and polysomnographic sleep parameters. Subjective sleep quality and RLS symptoms were evaluated using the Pittsburgh Sleep Quality Index (PSQI) and the International RLS study group (IRLSSG) rating scale.

SETTING

Sleep laboratory.

PARTICIPANTS

Ten pregnant women fulfilling the IRLSSG criteria for RLS diagnosis and 9 pregnant healthy controls underwent the protocol.

INTERVENTIONS

N/A.

RESULTS

Women with RLS showed higher levels of estradiol during pregnancy compared to controls (34,211 +/- 6397 pg/mL vs. 25,475 +/- 7990 pg/mL, P<0.05). Patients also showed more periodic limb movements (PLMs) before and after delivery, particularly during sleep stage 1 and wakefulness (P<0.05). PLMs decreased postpartum in subjects with RLS only (P<0.05); sleep efficiency increased in women without RLS and remained unchanged in patients (P<0.05). No significant differences were found between groups before or after delivery in plasma concentrations of prolactin, progesterone, testosterone, FSH, LH, iron, ferritin or hemoglobin.

CONCLUSIONS

RLS in pregnant women goes along with transiently increased estradiol levels and PLM indices suggesting that estrogens play a pathophysiological role for triggering RLS symptoms during pregnancy.

Effect of repeated gaboxadol administration on night sleep and next-day performance in healthy elderly subjects

Aging is associated with dramatic reductions in sleep continuity and sleep intensity. Since gaboxadol, a selective GABA(A) receptor agonist, has been demonstrated to improve sleep consolidation and promote deep sleep, it may be an effective hypnotic, particularly for elderly patients with insomnia. In the present study, we investigated the effects of subchronic gaboxadol administration on nocturnal sleep and its residual effects during the next days in elderly subjects. This was a randomized, double-blind, placebo-controlled, balanced crossover study in 10 healthy elderly subjects without sleep complaints. The subjects were administered either placebo or 15 mg gaboxadol hydrochloride at bedtime on three consecutive nights. Sleep was recorded during each night from 2300 to 0700 h and tests assessing attention (target detection, stroop test) and memory function (visual form recognition, immediate word recall, digit span) were applied at 0900, 1400, and 1700 h during the following days. Compared with placebo, gaboxadol significantly shortened subjective sleep onset latency and increased self-rated sleep intensity and quality. Polysomnographic recordings showed that it significantly decreased the number of awakenings, the amount of intermittent wakefulness, and stage 1, and increased slow wave sleep and stage 2. These effects were stable over the three nights. None of the subjects reported side effects. Next-day cognitive performance was not affected by gaboxadol. Gaboxadol persistently improved subjective and objective sleep quality and was devoid of residual effects. Thus, at the employed dose, it seems an effective hypnotic in elderly subjects.

Clozapine alters sleep-wake behavior in rats

Clozapine is an atypical antipsychotic agent showing therapeutic efficacy superior to that of classical neuroleptics. Clozapine has strong sedative effects, but detailed studies on the drug influencing sleep in rodents are lacking. We studied the effects of clozapine on sleep and body temperature in rats. Clozapine (0, 2.5, and 7.5 mg/kg) was given i.p. to male Wistar rats at the beginning of the rest period. After administration of 7.5 mg/kg clozapine, animals were significantly more awake during the first 2 h postinjection. In parallel, the slow-wave activity (SWA) was suppressed. In the following 2 h non-REM sleep was markedly increased, whereas the SWA returned to baseline. At both doses clozapine decreased overall wakefulness and increased non-REM sleep on the first treatment day, which was associated with prolonged non-REM sleep episodes. These effects were transiently present even after subchronic treatment (7 days). After acute treatment, 7.5 mg/kg clozapine significantly reduced REM sleep and pre-REM sleep due to an increase in REM sleep latency and a reduction in the number of REM sleep episodes. Furthermore, clozapine produced a transient decrease in brain temperature that was followed by a moderate, but long-lasting elevation. To conclude, clozapine affected sleep-wake behavior in a way comparable to its effects in humans, suggesting that the rat is a suitable model for further studies on the underlying mechanisms.

Intracerebral oxytocin modulates sleep-wake behaviour in male rats

Oxytocin released within the brain under basal conditions and in response to stress is differentially involved in the regulation of the hypothalamo-pituitary-adrenal (HPA) axis. Because the HPA axis plays an important role in the regulation of wakefulness, central oxytocin may modulate sleep-wake behaviour. In the present vehicle-controlled study, we assessed the influence of a selective oxytocin receptor antagonist (des-Gly-NH2d(CH2)5 [Tyr(Me)2,Thr4] OVT; 0.75 microg/5 microl) or of synthetic oxytocin (0.1 microg and 1 microg/5 microl), infused into the lateral ventricle (i.c.v.), on the sleep pattern in male Wistar rats (n=7). Compared to vehicle, the oxytocin antagonist slightly but persistently increased wakefulness at the expense of all sleep states. This finding indicates that endogenous brain oxytocin promotes sleep. However, acute icv infusion of oxytocin delayed sleep onset latency, which resulted in a transient reduction of non-REMS and REMS, and augmented high-frequency activity in the electroencephalogram (EEG) within non-REMS. These observations agree with previous reports that icv oxytocin induces a state of arousal. Based on these findings, we postulate that oxytocin has a dual mechanism of action in dependence of the physiological state. Under basal, stress-free conditions, endogenous oxytocin may promote sleep. Conversely, the high brain levels of oxytocin after central oxytocin infusion may reflect a condition of stress accompanied by behavioural arousal and, possibly via an excitatory action on the CRH system, increase vigilance.

Influence of regular voluntary exercise on spontaneous and social stress-affected sleep in mice

To investigate the impact of regular physical exercise on sleep, we assessed sleep-wake behaviour in male C57BL/6N mice with and without long-term access (i.e. 4 weeks) to a running wheel. We studied sleep-wake behaviour during undisturbed conditions as well as after social stress. The exercising mice ran approximately 4 km/day, which affected their physical constitution, their spontaneous sleep-wake pattern and their endocrine and sleep responses to stress. When compared with the control mice, exercising animals had more muscle substance, less body fat and heavier adrenal glands. At baseline, exercising mice showed fewer, but longer-lasting, sleep episodes (indicating improved sleep consolidation) and less rapid-eye-movement sleep. In both control and exercising mice, mild social stress (elicited by a 15-min social conflict) evoked elevated plasma levels of adrenocorticotrophic hormone and corticosterone, an increase in non-rapid-eye-movement sleep, an enhancement of low-frequency activity in the electroencephalogram within non-rapid-eye-movement sleep (indicating increased sleep intensity) and a decrease in wakefulness. However, as compared with the control animals, exercising mice responded to social stress with higher corticosterone levels, but not adrenocorticotrophic hormone levels, suggesting an increased sensitivity of their adrenal glands to adrenocorticotrophic hormone. Moreover, in control mice, social stress increased rapid-eye-movement sleep in parallel to non-rapid-eye-movement sleep, whereas this stressor selectively decreased rapid-eye-movement sleep in exercising animals. Corticosterone is known to decrease rapid-eye-movement sleep. Therefore, changes in the regulation of the hypothalamic-pituitary-adrenocortical axis as a result of the long-term exercise may contribute to the observed differences in spontaneous and social stress-affected sleep. In conclusion, regular exercise appears to increase sleep quality and reverses the effects of mild social stress on rapid-eye-movement sleep.

Effect of sleep and sleep deprivation on serotonergic neurotransmission in the hippocampus: a combined in vivo microdialysis/EEG study in rats

Brainstem serotonergic neurotransmission is implicated in sleep regulation. However, the role of serotonin (5-HT) in forebrain regions in sleep-wake mechanisms is still unclear. Here, we have investigated, using a combined in vivo microdialysis/electroencephalogram method, the relationship between hippocampal 5-HT levels and sleep-wake behaviour in the rat. A clear-cut relationship was found between hippocampal 5-HT levels and vigilance state. The highest levels of 5-HT were observed during wakefulness, whereas a progressive decrease of 5-HT going from nonrapid eye movement sleep to rapid eye movement sleep was found. Sleep deprivation (SD) causes a transient enhancement of mood in depressed patients. Given the putative role of 5-HT in the aetiology of depression and the therapeutical efficacy of selective serotonin reuptake inhibitors in this illness, we also studied hippocampal 5-HT during 4 h of SD and during the subsequent recovery period. During the whole SD period, 5-HT levels were elevated substantially when compared to 5-HT levels during basal wakefulness. However, no changes in 5-HT levels and the relationship between hippocampal 5-HT and vigilance state were found during the subsequent recovery period. As SD is a potentially stressful experience and glucocorticoids are involved in the regulation of serotonergic neurotransmission and sleep, we investigated the effects of SD on free corticosterone levels. SD caused a marked rise in free corticosterone levels. However, the effects of SD on 5-HT seem not to be mediated by this hormone, because adrenalectomy did not affect the rise in hippocampal 5-HT during SD. We hypothesize that the elevated hippocampal 5-HT levels during SD may participate in the transient mood enhancing properties of forced wakefulness observed in depressed patients.

Absence epilepsy and sinus dysrhythmia in mice lacking the pacemaker channel HCN2

Hyperpolarization-activated cation (HCN) channels are believed to be involved in the generation of cardiac pacemaker depolarizations as well as in the control of neuronal excitability and plasticity. The contributions of the four individual HCN channel isoforms (HCN1-4) to these diverse functions are not known. Here we show that HCN2-deficient mice exhibit spontaneous absence seizures. The thalamocortical relay neurons of these mice displayed a near complete loss of the HCN current, resulting in a pronounced hyperpolarizing shift of the resting membrane potential, an altered response to depolarizing inputs and an increased susceptibility for oscillations. HCN2-null mice also displayed cardiac sinus dysrhythmia, a reduction of the sinoatrial HCN current and a shift of the maximum diastolic potential to hyperpolarized values. Mice with cardiomyocyte- specific deletion of HCN2 displayed the same dysrhythmia as mice lacking HCN2 globally, indicating that the dysrhythmia is indeed caused by sinoatrial dysfunction. Our results define the physiological role of the HCN2 subunit as a major determinant of membrane resting potential that is required for regular cardiac and neuronal rhythmicity.

The CRH1 receptor antagonist R121919 attenuates stress-elicited sleep disturbances in rats, particularly in those with high innate anxiety

Excessive corticotropin-releasing hormone (CRH) secretion in limbic and prefrontal brain areas has been postulated to underly stress-related clinical conditions. Studies in mice with deleted or pharmacologically compromised CRH type 1 receptors (CRH-R1) point to a key role of the CRH/CRH-R1 signaling cascade as a potential drug target. Therefore, we compared the effect of a selective high affinity CRH-R1 antagonist (R121919) on sleep-wake behavior in two rat lines selectively bred for either high or low innate anxiety. We found that the subcutaneous injection of the solvent of R121919, a citrate buffer solution, transiently increased circulating levels of the stress hormones ACTH and corticosterone and reduced sleep, especially in high-anxiety animals. When R121919 was added to the solvent, hormone levels and sleep patterns returned to baseline and were indistinguishable between the rat lines. This finding is in accord with previous observations from a clinical trial in depressed patients and studies in rats with high innate anxiety that suggested major effects of CRH-R1 antagonism in the presence of a pathological (i.e. CRH hypersecretion) condition only.

Assessment of spontaneously occurring periodic limb movements in sleep in the rat

OBJECTIVE

Periodic limb movements in sleep (PLMS) are often associated with the restless legs syndrome (RLS). Although the dopaminergic system seems to be involved, the pathophysiology of PLMS and RLS is still obscure. The objective of this study is to explore whether a PLMS-like phenomenon can be observed in rodents in order to elucidate the underlying mechanisms.

METHODS

In a group of young and old rats (1.4-1.6 and 16.2-20.5 months, respectively), sleep-wake behavior was recorded and hindlimb movements were detected by means of a magneto-inductive device during two 12-h light periods. Furthermore, in the old rats, recordings were made after administration of the dopamine antagonist haloperidol (HAL) on three consecutive days. Periodic hindlimb movements (PHLM) during nonrapid eye movement sleep (NREM) were identified according to modified human criteria.

RESULTS

In the young animals, no PHLM were observed, whereas, 4 out of 10 old rats showed PHLM, two of them have more than 5 PHLM/h. Haloperidol affects neither the sleep pattern nor the number of PHLM. Interestingly, the percentage of old rats spontaneously displaying PHLM resembles the prevalence of PLMS in the elderly.

CONCLUSIONS

Our study demonstrates for the first time that periodic hindlimb movements (PHLM) in sleep can occur spontaneously in rats. A clear effect of age on this phenomenon was seen, with only old animals displaying PHLM. To validate whether the observed PHLM constitute a good model for human PLMS or even RLS, their pharmacological properties need to be characterized in a large number of PHLM positive animals.

The effects of the neuroactive steroid 3 alpha,5 alpha-THDOC on sleep in the rat

This vehicle-controlled study assessed the sleep effects of the naturally occurring neuroactive steroid 3alpha,5alpha-tetrahydrodeoxycorticosterone (3alpha,5alpha-THDOC; 7.5 and 15 mg/kg), administered i.p. to rats, and compared them with those of another neuroactive steroid allopregnanolone (15 mg/kg). 3alpha,5alpha-THDOC shortened sleep latency, selectively promoted pre-REMS (a transitional state between non-REMS and REMS) and lengthened the non-REMS episodes dose-dependently. Spectral analysis of the EEG within non-REMS found significant attenuations of low-frequency activity and elevations in the spindle and higher frequency bands. The effects of 3alpha,5alpha-THDOC closely match those of allopregnanolone, indicating a common mechanism of action. Since the sleep changes produced by these steroids resemble the sleep profile of benzodiazepine hypnotics, they are probably caused by a positive allosteric modulation of GABAA receptor function.

Neuroactive steroids: molecular mechanisms of action and implications for neuropsychopharmacology

Besides their binding to cognate intracellular receptors gonadal steroids may also act as functional antagonists at the 5-HT3 receptor. A structure-activity relationship for the actions of a variety of steroids at the 5-HT3 receptor was elaborated that differed considerably from that known for GABA(A) receptors. Steroids appear to interact allosterically with ligand-gated ion channels at the receptor membrane interface. The functional antagonism of gonadal steroids at the 5-HT3 receptor may play a role for the development and course of nausea during pregnancy and of psychiatric disorders. Moreover, we could demonstrate that 3alpha-reduced neuroactive steroids concurrently modulate the GABA(A) receptor and regulate gene expression via the progesterone receptor after intracellular oxidation. Animal studies showed that progesterone is converted rapidly into GABAergic neuroactive steroids in vivo. Progesterone reduces locomotor activity in a dose dependent fashion in male Wister rats. Moreover, progesterone and 3alpha,5alpha-tetrahydroprogesterone produce a benzodiazepine-like sleep EEG profile in rats and humans. In addition, there is a dysequilibrium of such 3alpha-reduced neuroactive steroids during major depression which is corrected by successful treatment with antidepressants. Neuroactive steroids may further be involved in the treatment of depression and anxiety with antidepressants in patients during ethanol withdrawal. First studies in patients with panic disorder suggest that neuroactive steroids may also play a pivotal role in human anxiety. The genomic and non-genomic effects of steroids in the brain contribute to the pathophysiology of psychiatric disorders and the mechanisms of action of antidepressants. Neuroactive steroids affect a broad spectrum of behavioral functions through their unique molecular properties and may constitute a yet unexploited class of drugs.

The influence of subchronic administration of the neurosteroid allopregnanolone on sleep in the rat

The endogenous neurosteroid allopregnanolone has recently been demonstrated to have somnogenic properties that are very similar to those of other agonistic modulators of GABA(A) receptors, especially of short-acting benzodiazepines. Short-acting benzodiazepines are established to rapidly lose their hypnotic effect upon repeated administration. To investigate the tolerance potential of allopregnanolone, we assessed sleep-wake behavior in rats during subchronic treatment (once daily for five days) with placebo or 15 mg/kg allopregnanolone (n = 8 each). The sleep patterns of the placebo and allopregnanolone group did not differ significantly before and after treatment. Throughout the entire treatment period the allopregnanolone group exhibited shorter non-rapid eye movement sleep (non-REMS) latencies, prolonged REMS latencies, longer non-REMS episodes, more pre-REMS and less low-frequency, but higher spindle activity in the electroencephalogram (EEG) within non-REMS than the placebo group. The lack of tolerance effects suggests that allopregnanolone may be an efficacious modulator of sleep-wake behavior over longer time periods than most drugs targeting the benzodiazepine binding site of the GABA(A) receptor.

The GABA(A) agonist gaboxadol improves the quality of post-nap sleep

RATIONALE

Previous studies demonstrated that gaboxadol, a selective GABA(A) agonist, increases both non-REM sleep and EEG delta activity within non-REM sleep in rats and slow wave sleep (SWS) as well as low-frequency activity in the EEG within non-REM sleep in healthy humans under normal conditions.

OBJECTIVE

Because the hypnotic actions of drugs may be more readily demonstrated under conditions of poor sleep quality, we investigated the influence of gaboxadol on postnap sleep.

METHODS

In a randomized, placebo-controlled cross-over study using a late afternoon nap model, we assessed the effects of a single oral dose of 20 mg gaboxadol on disturbed nighttime sleep in young, healthy subjects.

RESULTS

Comparisons of visually scored sleep parameters between baseline and placebo postnap nights showed that the nap prolonged sleep latency, decreased total sleep time and SWS and attenuated delta, theta and alpha activity in the EEG within non-REM sleep. Compared with the placebo postnap night, gaboxadol tended to shorten sleep latency, significantly decreased intermittent wakefulness, increased total sleep time and SWS and enhanced delta and theta activity in the non-REM EEG. Furthermore, gaboxadol increased subjective sleep quality.

CONCLUSIONS

These data show that gaboxadol counteracts the disrupting effects of a nap on subsequent sleep and suggest that, in addition to promoting deep sleep and sleep maintenance, gaboxadol is able to facilitate sleep initiation and thus, exhibits significant hypnotic actions under conditions in which sleep quality is experimentally reduced.

Acute effects of melatonin on spontaneous and picrotoxin-evoked sleep-wake behaviour in the rat

Various studies indicate that exogenous melatonin has hypnotic properties in humans, which may be mediated by its influence on the circadian timing system or direct sleep-promoting actions, e.g. through a modulation of GABAergic transmission. The aim of the present placebo-controlled study was to examine the effects of melatonin on sleep in rats and the contribution of gamma-aminobutyric acid (GABA)A receptors. Sleep-wake behaviour was assessed in nine rats after intraperitoneal (i.p.) administration of pharmacological doses of melatonin (5 and 10 mg kg(-1)) and after combined administration of the GABAA receptor antagonist picrotoxin (1.5 mg kg(-1)) and melatonin (10 mg kg(-1)). To prevent chronobiotic effects, melatonin was delivered in the middle of the light period. Neither doses of melatonin exerted significant effects on brain temperature, sleep architecture or sleep electroencephalogram (EEG). Moreover, melatonin failed to attenuate the picrotoxin-induced promotion of wakefulness. These observations indicate that melatonin hardly influences sleep-wake behaviour in rats.

Effect of the GABAA agonist gaboxadol on nocturnal sleep and hormone secretion in healthy elderly subjects

Aging is associated with a dramatic decrease in sleep intensity and continuity. The selective GABA(A) receptor agonist gaboxadol has been shown to increase non-REM sleep and the duration of the non-REM episodes in rats and sleep efficiency in young subjects and to enhance low-frequency activity in the electroencephalogram (EEG) within non-REM sleep in both rats and humans. In this double-blind, placebo-controlled study, we investigated the influence of an oral dose of 15 mg of gaboxadol on nocturnal sleep and hormone secretion (ACTH, cortisol, prolactin, growth hormone) in 10 healthy elderly subjects (6 women). Compared with placebo, gaboxadol did not affect endocrine activity but significantly reduced perceived sleep latency, elevated self-estimated total sleep time, and increased sleep efficiency by decreasing intermittent wakefulness and powerfully augmented low-frequency activity in the EEG within non-REM sleep. These findings indicate that gaboxadol is able to increase sleep consolidation and non-REM sleep intensity, without disrupting REM sleep, in elderly individuals and that these effects are not mediated by a modulation of hormone secretion.

The GABA uptake inhibitor tiagabine promotes slow wave sleep in normal elderly subjects

Aging is associated with a dramatic decrease in slow wave sleep (SWS) and sleep consolidation. Previous studies revealed that various GABA(A) agonists and the GABA uptake inhibitor tiagabine augment slow frequency components in the EEG within non-REM sleep, and thus promote deep sleep in young individuals and/or rats. In the present double-blind, placebo-controlled study, we assessed the effect of a single oral dose of 5 mg tiagabine on nocturnal sleep in ten healthy elderly volunteers (6 females). During the placebo night the subjects displayed a low sleep efficiency, due to high amounts of intermittent wakefulness, and little SWS. Tiagabine significantly increased sleep efficiency, tendentially decreased wakefulness and prominently increased both SWS and low-frequency activity in the EEG within non-REM sleep. The present findings demonstrate that tiagabine increases sleep quality in aged subjects. Moreover, the effects of tiagabine closely match those evoked by the GABA(A) agonist gaboxadol in young subjects and indicate that such compounds may have prospects in the treatment of sleep disturbances, particularly of those commonly occurring in the elderly.

Sleep changes induced by lipopolysaccharide in the rat are influenced by age

In mammals, aging is associated with immune senescense. To examine whether the sleep changes occurring during immune challenge are affected by age, we assessed sleep alterations induced by the administration of lipopolysaccharide (LPS) in young and middle-aged rats. During vehicle, the middle-aged rats exhibited less pre-rapid eye movement sleep (pre-REMS) as well as REMS, due to a smaller number and shorter duration of REMS episodes, than young rats. LPS elevated body temperature, increased non-REMS, and suppressed both pre-REMS and REMS in the young as well as in the middle-aged rats. However, in the young animals, LPS significantly enhanced slow-wave activity in the electroencephalogram (EEG) within non-REMS, reflecting an increase in sleep intensity. In contrast, LPS attenuated EEG power in most frequency bands in the older animals. This finding indicates age-related changes in the modulation of sleep by LPS.

gamma-aminobutyric Acid(A) (GABA(A)) agonist 4,5,6, 7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol persistently increases sleep maintenance and intensity during chronic administration to rats

Many hypnotics, such as benzodiazepines, are agonistic modulators of gamma-aminobutyric acid(A) (GABA(A)) receptors. Such compounds increase the ability to fall and stay asleep, but inhibit rapid-eye movement (REM) sleep and deep non-REM sleep. However, tolerance to their hypnotic action may develop rapidly. Previous findings in rats and humans demonstrate that the gamma-aminobutyric acid(A) agonist 4, 5,6,7-tetrahydroisoxazolo[4,5-c]pyridin-3-ol (THIP) promotes deep non-REM sleep and increases non-REM sleep continuity. To investigate the effects of repeated administration, we assessed sleep in rats before, during, and after chronic dosing of THIP (3 mg/kg, once daily for 5 days; n = 9) or of placebo (n = 8). The substances were administered i.p. at the onset of darkness. The electroencephalogram (EEG) and electromyogram were recorded during the first 6 h after injection. During baseline recording, the placebo and the THIP group exhibited similar sleep patterns. After the first THIP injection, rats displayed more non-REM sleep, longer non-REM episodes, and higher levels of slow wave activity in the EEG within non-REM sleep than the placebo group rats. The effects were sustained during all treatment days. REM sleep was not affected. After drug withdrawal, the sleep patterns of the THIP and the placebo group were practically identical again. These observations suggest that THIP does not rapidly produce tolerance toward its sleep effects and abrupt drug withdrawal may not be associated with sleep disturbances. These findings confirm and extend the existing information suggesting that THIP may be promising for treatment of insomnia.

Diurnal variations in lipopolysaccharide-induced sleep, sickness behavior and changes in corticosterone levels in the rat

Inoculation of rats with microorganisms or microbial constituents that activate host defense promotes non-rapid eye movement sleep (non-REMS) and suppresses REMS. In this study, we evaluated circadian influences on the effects of lipopolysaccharide (LPS) on sleep, sickness behavior and plasma corticosterone levels in the rat. Three sets of experiments were performed. In each, the animals were intraperitoneally injected with vehicle for LPS (30 microg/kg) during 2 consecutive days, at the beginning of either the circadian rest or the activity phase. In experiment 1, sleep-wake behavior and brain temperature were recorded, and in experiment 2, core body temperature, locomotor activity as well as food and water intake. In experiment 3, corticosterone blood levels were measured. The results show that LPS-evoked changes in temperature, sleep and other behavioral parameters depend markedly on the time of day LPS is administered. However, a direct comparison of the LPS data demonstrates that, except for sleep parameters, the absolute time course of the assessed parameters was rather similar between the rest and activity phases. These findings suggest that LPS evokes a state characterized by high temperature and low vigilance, which is reached independently of the circadian phase.

High doses of systemic DHEA-sulfate do not affect sleep structure and elicit moderate changes in non-REM sleep EEG in rats

The hormone dehydroepiandrosterone (DHEA) and its metabolite DHEA-sulfate (DHEAS) occur in huge quantities in the plasma as well as in the brain of vertebrates. To investigate whether DHEAS modulates sleep-wake behavior, we assessed the sleep response to three doses (25, 50, and 100 mg/kg) of intraperitoneally administered DHEAS, mixed with oil, in 8 rats. DHEAS injections produced dose-dependent and long-lasting elevations in the plasma levels of both DHEAS and DHEA. DHEAS administration did not affect sleep time and architecture but exerted persistent effects on the electroencephalogram (EEG) within non-rapid eye movement sleep: 50 mg/kg DHEAS significantly augmented EEG power in the frequency range of sleep spindles, and 100 mg/kg DHEAS depressed EEG power in the slow-wave frequency bands. The findings indicate that DHEAS changes the sleep EEG in a dose-dependent way, possibly through a modulation of GABA- and glutamate-induced currents.

Sleep and Its Modulation by Drugs That Affect GABA(A) Receptor Function

Most sleeping pills are made up of chemical compounds that are ligands for allosteric modulatory binding sites on the GABA(A) receptor. Polysomnographic studies demonstrate that these hypnotics effectively increase the ability to fall and to stay asleep, but disrupt the physiological sleep profile (typical electroencephalograms (EEG) for the awake state and the different states of sleep are shown). Hence, there is an urgent need for sleep-promoting substances with a different mechanism of action. GABA analogues are one class of promising molecules.