Sleep and depression--results from psychobiological studies: an overview

Does effective management of sleep disorders reduce depressive symptoms and the risk of depression?

The link between co-morbid insomnia and depression has been demonstrated in numerous groups. Insomnia has been associated with: (1) an increased risk of developing subsequent depression; (2) an increased duration of established depression; and (3) relapse following treatment for depression. In addition, specific insomnia symptoms, such as nocturnal awakening with difficulty resuming sleep, are more strongly associated with depression than classic symptoms of insomnia. Participants of a workshop, held at the 6th annual meeting of The International Sleep Disorders Forum: The Art of Good Sleep in 2008, evaluated whether the effective management of sleep disorders could reduce both concurrent depressive symptoms and the risk of developing subsequent depression. Following the workshop, a targeted literature review was conducted. Initial evidence demonstrated that in patients with insomnia and co-morbid depression either pharmacological treatment of insomnia or psychological treatment in the form of cognitive behavioural therapy for insomnia improved both insomnia and depressive symptoms. Although these appeared to be promising treatment strategies, however, of the 27 identified treatment studies, only one large well-designed randomized controlled trial comparing the efficacy of eszopiclone plus fluoxetine with placebo plus fluoxetine demonstrated unequivocal evidence that improvements in insomnia symptoms conferred additive benefits on depressive outcomes. In addition, it was unclear whether any differences exist in efficacy between sedating versus non-sedating pharmacotherapies for insomnia in this patient group. Further studies of sufficient sample size and duration are needed to evaluate combinations of pharmacological (either sedating or non-sedating) and psychological interventions in co-morbid insomnia and depression. This article reviews the level of evidence, recommendations and areas of particular interest for further study and discussion arising from this workshop.

Sleep and emotions: a focus on insomnia

Insomnia disorder is defined as difficulties in initiating/maintaining sleep and/or non-restorative sleep accompanied by decreased daytime functioning, persisting for at least four weeks. For many patients suffering from depression and anxiety, insomnia is a pervasive problem. Many of the aetiological theories of insomnia postulate that heightened emotional reactivity contributes to the maintenance of symptoms. This review focuses on the role of emotional reactivity in insomnia, and how the relationship between insomnia and depression and anxiety may be mediated by emotional reactivity. Furthermore, studies investigating the valence of emotions in insomnia are reviewed. Overall, there is empirical evidence that dysfunctional emotional reactivity might mediate the interaction between cognitive and autonomic hyperarousal, thus contributing to the maintenance of insomnia. Moreover, dysfunctions in sleep-wake regulating neural circuitries seem to be able to reinforce emotional disturbances. It seems plausible that dysfunctional emotional reactivity modulates the relationship between insomnia and depression and anxiety. Considering the interaction between sleep and emotional valence, poor sleep quality seems to correlate with high negative and low positive emotions, both in clinical and subclinical samples. Good sleep seems to be associated with high positive emotions, but not necessarily with low negative emotions. This review underlines the need for future research on emotions in insomnia.

Maternal psychological control and child internalizing symptoms: vulnerability and protective factors across bioregulatory and ecological domains

BACKGROUND

We examined ecological (family socioeconomic status (SES)) and bioregulatory (sleep duration, sleep efficiency) moderators of the link between maternal psychological control and children's vulnerability to internalizing symptoms.

METHOD

A large socioeconomically diverse sample of third graders (N = 141) and their mothers participated. Sleep was examined via actigraphy for one week. Psychological control and internalizing symptoms (depressive symptoms, anxiety symptoms, pre-sleep arousal) were examined through children's reports.

RESULTS

For children with poorer sleep, lower SES, or a combination of the two, maternal psychological control was positively related to depressive symptoms; this association was not evident for children with both better sleep and higher SES. Further, maternal psychological control, sleep efficiency, and SES interacted to predict both anxiety symptoms and pre-sleep arousal. Children were protected from the negative effects of psychological control when they were from higher SES families and had higher sleep efficiency; for all other groups of children, psychological control was associated with anxiety symptoms. A similar but less robust pattern of results was found for pre-sleep arousal.

CONCLUSIONS

Findings highlight the importance of children's bioregulatory processes within the socioeconomic context for an enhanced understanding of children's vulnerability to internalizing problems in the context of maternal psychological control.

Cognitive neuroscience of sleep

Mechanism is at the heart of understanding, and this chapter addresses underlying brain mechanisms and pathways of cognition and the impact of sleep on these processes, especially those serving learning and memory. This chapter reviews the current understanding of the relationship between sleep/waking states and cognition from the perspective afforded by basic neurophysiological investigations. The extensive overlap between sleep mechanisms and the neurophysiology of learning and memory processes provide a foundation for theories of a functional link between the sleep and learning systems. Each of the sleep states, with its attendant alterations in neurophysiology, is associated with facilitation of important functional learning and memory processes. For rapid eye movement (REM) sleep, salient features such as PGO waves, theta synchrony, increased acetylcholine, reduced levels of monoamines and, within the neuron, increased transcription of plasticity-related genes, cumulatively allow for freely occurring bidirectional plasticity, long-term potentiation (LTP) and its reversal, depotentiation. Thus, REM sleep provides a novel neural environment in which the synaptic remodelling essential to learning and cognition can occur, at least within the hippocampal complex. During non-REM sleep Stage 2 spindles, the cessation and subsequent strong bursting of noradrenergic cells and coincident reactivation of hippocampal and cortical targets would also increase synaptic plasticity, allowing targeted bidirectional plasticity in the neocortex as well. In delta non-REM sleep, orderly neuronal reactivation events in phase with slow wave delta activity, together with high protein synthesis levels, would facilitate the events that convert early LTP to long-lasting LTP. Conversely, delta sleep does not activate immediate early genes associated with de novo LTP. This non-REM sleep-unique genetic environment combined with low acetylcholine levels may serve to reduce the strength of cortical circuits that activate in the ~50% of delta-coincident reactivation events that do not appear in their waking firing sequence. The chapter reviews the results of manipulation studies, typically total sleep or REM sleep deprivation, that serve to underscore the functional significance of the phenomenological associations. Finally, the implications of sleep neurophysiology for learning and memory will be considered from a larger perspective in which the association of specific sleep states with both potentiation or depotentiation is integrated into mechanistic models of cognition.

Sex differences in subjective and actigraphic sleep measures: a population-based study of elderly persons

STUDY OBJECTIVES

To investigate and explain sex differences in subjective and actigraphic sleep parameters in community-dwelling elderly persons.

DESIGN

Cross-sectional study.

SETTING

The study was embedded in the Rotterdam Study, a population-based study.

PARTICIPANTS

Nine hundred fifty-six participants aged 59 to 97 years.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Participants wore an actigraph and kept a sleep diary for an average of 6 consecutive nights. Subjective sleep quality was assessed with the Pittsburgh Sleep Quality Index. Unadjusted sex differences in sleep parameters were assessed with t tests. Women reported shorter total sleep time, a less favorable sleep-onset latency, lower sleep efficiency, and worse global sleep quality, as compared with men. When assessed with actigraphy, however, women were found to have longer and less-fragmented sleep than men. Sex differences in diary-reported sleep duration and other subjective sleep parameters were attenuated by adjustment for marital status, the use of sleep medication, and other covariates, but all sex differences remained significant in a multivariate-adjusted model. Sex differences in actigraphic sleep parameters were barely attenuated by multivariate adjustment, although the shorter actigraphically measured sleep duration in men was partly explained by their higher alcohol consumption. Some covariates (eg, sleep medication) had a different relationship with diary-reported or actigraphic total sleep time in men and women.

CONCLUSIONS

If assessed by diary or interview, elderly women consistently reported shorter and poorer sleep than elderly men. In contrast, actigraphic sleep measures showed poorer sleep in men. These discrepancies are partly explained by determinants of sleep duration, such as sleep medication use and alcohol consumption.

Insomnia and depression: a multifaceted interplay

Historically, insomnia has been viewed as a symptom of depressive illness that is expected to resolve with adequate treatment of the depressive disorder. This article reviews the evidence that increasingly challenges this simplistic view and summarizes research demonstrating the multifaceted interplay between insomnia and depression. It discusses the prevalence, clinical significance, and time course of insomnia, distinguishing between poor sleep and an insomnia disorder. The article also discusses abnormalities in sleep architecture in major depressive disorder and theories about the pathways connecting sleep and depression. It concludes with a discussion of issues related to treatment, including the effects of antidepressants on sleep and new evidence of the utility of adding an insomnia-specific therapy for improved management of depressed patients with comorbid insomnia.

Comorbidity of insomnia and depression

During the last decade, several studies have shown that insomnia, rather than a symptom of depression, could be a medical condition on its own, showing high comorbidity with depression. Epidemiological research indicates that insomnia could lead to depression and/or that common causalities underlie the two disorders. Neurobiological and sleep EEG studies suggest that a heightened level of arousal may play a common role in both conditions and that signs of REM sleep disinhibition may appear in individuals prone to depression. The effects of antidepressant drugs on non-REM and REM sleep are discussed in relation to their use in insomnia comorbid with depression. Empirical treatment approaches are behavioral management of sleep combined with prescription of a sedative antidepressant alone, co-prescription of two antidepressants, or of an antidepressant with a hypnotic drug.

Depression is associated with worse objectively and subjectively measured sleep, but not more frequent awakenings, in women with vasomotor symptoms

OBJECTIVE

Depression occurs more commonly during the menopausal transition in women with vasomotor symptoms (VMS) than in those without, but most women with VMS do not develop depression. It has been hypothesized that VMS are associated with depression because VMS lead to repeated awakenings, which impair daytime well-being. We aimed to determine if objectively measured sleep and perceived sleep quality are worse in depressed women with VMS than in nondepressed women with VMS.

METHODS

Objectively and subjectively measured sleep parameters were compared between 52 depressed women with VMS and 51 nondepressed controls with VMS. Actigraphic measures of objective sleep conducted in the home environment and subjective measures of sleep quality (Pittsburgh Sleep Questionnaire Index) were compared using linear regression models.

RESULTS

On objective assessments, depressed women with VMS spent less time in bed (by 64.8 min; P < 0.001) and had shorter total sleep time (by 47.7 min; P = 0.008), longer sleep-onset latency (by 13.8 min; P = 0.03), and lower sleep efficiency (by 3.2 percentage points; P = 0.09), but did not awaken more or spend more time awake after sleep onset than nondepressed controls with VMS. Depressed women also reported worse sleep quality (mean Pittsburgh Sleep Questionnaire Index 12.0 vs 8.3; P < 0.001). Adjustment for VMS frequency and important demographic characteristics did not alter these associations.

CONCLUSIONS

Sleep quality and selected parameters of objectively measured sleep, but not sleep interruption, are worse in depressed than in nondepressed women with VMS. The type of sleep disturbance seen in depressed participants was not consistent with the etiology of depression secondary to VMS-associated awakenings.

Disruptions of the mother-infant relationship and stress-related behaviours: altered corticosterone secretion does not explain everything

The hypothalamic-pituitary-adrenal (HPA) axis is the main neuroendocrine system of response to stress, and an imbalance of this system's activity is believed to be at the core of numerous psychiatric pathologies. During the neonatal period, the glucocorticoid response to stress is maintained at low levels by specific maternal behaviours, which is essential for proper brain development. Effective evaluation of the impact of increased secretion of corticosterone during an essentially anabolic developmental period on adulthood behaviour involved separation of the neonate from its mother for periods ranging from 3 to 24h. It has been shown that disinhibition of the stress response is achieved by such procedures. The pioneering studies by Seymour Levine set the stage for a prolific and promising field of study that may help neuroscientists unveil the neurobiological underpinnings of stress-related disorders. Based on a series of studies, we propose that maternal separation and maternal deprivation change stress-related behaviours, but that corticosterone seem to be only partially involved in these changes in adulthood. It appears that extra-hypothalamic corticotrophin-releasing factor and neurotransmitter systems may be the primary mediators of these behavioural outcomes.

Recurrence of depression during pregnancy: psychosocial and personal functioning correlates

BACKGROUND

This study examined psychosocial and personal functioning during pregnancy in women at risk for depression recurrence based on having had at least one major depressive episode (MDE) preceding the pregnancy.

METHODS

Three groups of women, who differed in recurrence of depression during pregnancy, were compared: (1) women who had at least one recurrent episode meeting diagnostic criteria for a MDE (n=23), (2) women who had a recurrence of clinically significant levels of depressive symptoms but did not meet criteria for a MDE (n=18), and (3) women who had no recurrence of depression (n=38) during pregnancy.

RESULTS

Results indicated that recurrences of depression during pregnancy are associated with a range of psychosocial and personal functioning correlates. Furthermore, the correlates of depression during pregnancy were the same for women who met diagnostic criteria for MDE and women who had subthreshold levels of depression.

CONCLUSIONS

The findings support extending psychosocial models of depression to depression recurrence during pregnancy with an emphasis on the broader context within which depression occurs. The findings also have implications for understanding subclinical depression during pregnancy as being associated with problems in functioning equal in severity and breadth to episodes of major depression.

The effect of clomipramine on wake/sleep and orexinergic expression in rats

We have previously found that neonatal treatment with clomipramine (CLI) induced a decrease in brain orexins during the juvenile period and that these changes were reversed at adulthood. This study investigated the effect of CLI on the orexinergic component and sleep/wake states. Two groups of adult male rats were conducted for 48-h polysomnographic recording. One group of rats was treated with CLI (20 mg/kg every 12 h), and a second group was treated with equivolume of saline (SAL) simultaneously after the first 24 h of polysomnographic recording. Rats were killed 2 h after the third dose of treatment. Brain tissues were collected for radioimmunoassay quantification of orexins and real-time PCR analysis of prepro-orexin and orexin receptor mRNA. The CLI group had significantly shorter rapid eye movement (REM) sleep and longer REM latency compared with both the baseline day and the SAL group and had significantly less active wake and more quiet wake. Compared with the control rats, the CLI rats had significantly higher mRNA expression of prepro-orexin in the hypothalamus and the frontal cortex, but not in the hippocampus. The CLI rats also had significantly less orexin B in the hypothalamus than the control rats. These results suggest that suppression of active wake and orexin B by CLI may be a factor responsible for CLI-induced depression and that the increase of prepro-orexin mRNA may be a sign of increased brain orexins found in this model.

The effect of trimipramine on dream recall and dream emotions in depressive outpatients

Trimipramine is a sedating tricyclic antidepressant which is not only effective in the treatment of depression but also in primary insomnia. In contrast to most other antidepressants, trimipramine does not affect rapid eye movement sleep. In a large sample of depressive outpatients (N = 3926), the effect of trimipramine on dream recall and dream emotions was studied. The effect of trimipramine on dream recall was small and might be explained by the reduction of negatively toned dreams. The 4-week treatment with trimipramine yielded a considerable shift in dream emotions towards the positive end of the scale, which is paralleled by the decrease of symptom severity. The present findings support the continuity hypothesis of dreaming by demonstrating a close link between waking-life symptomatolgy and negative dream emotions. Future studies should analyze dream content in order to support the hypothesis that improvement in day-time symptoms is reflected in patients' dreams.

The hyperarousal model of insomnia: a review of the concept and its evidence

Primary insomnia is defined as difficulties in falling asleep, maintaining sleep or non-restorative sleep accompanied by significantly impaired daytime functioning in the absence of a specific physical, mental or substance-related cause. The current review provides substantial support for the concept that hyperarousal processes from the molecular to the higher system level play a key role in the pathophysiology of primary insomnia. Autonomous, neuroendocrine, neuroimmunological, electrophysiological and neuroimaging studies demonstrate increased levels of arousal in primary insomnia during both night and daytime. In the light of neurobiological theories of sleep-wake regulation, primary insomnia may be conceptualized as a final common pathway resulting from the interplay between a genetic vulnerability for an imbalance between arousing and sleep-inducing brain activity, psychosocial/medical stressors and perpetuating mechanisms including dysfunctional sleep-related behavior, learned sleep preventing associations and other cognitive factors like tendency to worry/ruminate.

Sleep-related memory consolidation in depression: an emerging field of research

Sleep-related memory consolidation has received increasing attention in recent years. Because previous research has focused on healthy young adults, only very few studies have been conducted in patients with psychiatric disorders so far. The investigation of sleep-related memory consolidation in depression offers a wide range of future research opportunities and can therefore be regarded as an emerging field of research. This article gives a short overview of current knowledge of sleep-related memory consolidation in healthy young adults and builds a bridge to psychiatry and depression, where further research is urgently needed.

Pathophysiology of depression: role of sleep and the melatonergic system

Profound disturbances in sleep architecture occur in major depressive disorders (MDD) and in bipolar affective disorders. Reduction in slow wave sleep, decreased latency of rapid eye movement (REM) sleep and abnormalities in the timing of REM/non-REM sleep cycles have all been documented in patients with MDD. It is thus evident that an understanding of the basic mechanisms of sleep regulation is essential for an analysis of the pathophysiology of depressive disorders. The suprachiasmatic nucleus (SCN), which functions as the body's master circadian clock, plays a major role in the regulation of the sleep/wakefulness rhythm and interacts actively with the homeostatic processes that regulate sleep. The control of melatonin secretion by the SCN, the occurrence of high concentrations of melatonin receptors in the SCN, and the suppression of electrical activity in the SCN by melatonin all underscore the major influence which this neurohormone has in regulating the sleep/wake cycle. The transition from wakefulness to high sleep propensity is associated with the nocturnal rise of endogenous melatonin secretion. Various lines of evidence show that depressed patients exhibit disturbances in both the amplitude and shape of the melatonin secretion rhythm and that melatonin can improve the quality of sleep in these patients. The choice of a suitable antidepressant that improves sleep quality is thus important while treating a depressive disorder. The novel antidepressant agomelatine, which combines the properties of a 5-HT(2C) antagonist and a melatonergic MT(1)/MT(2) receptor agonist, has been found very effective for resetting the disturbed sleep/wake cycle and in improving the clinical status of MDD. Agomelatine has also been found useful in treating sleep problems and improving the clinical status of patients suffering from seasonal affective disorder.

Longitudinal study on poor sleep and life dissatisfaction in a nationwide cohort of twins

Life satisfaction and quality of sleep are important, related components of subjective well-being and general health. However, no earlier investigation is known to have tested the direction of the temporal relation between poor sleep and diminished life satisfaction, including simultaneous examination of shared genetic influences. These features were examined in the present study of a nationwide cohort of 18,631 same-sex Finnish twins with repeated measurements of life satisfaction, sleep quality, and several potential confounders within an interval of 6 years (1975 and 1981). Most individuals (59%) with new-onset life dissatisfaction had experienced suboptimal sleep at baseline. Poor sleep predicted a consistent pattern of life dissatisfaction (odds ratio = 2.1, 95% confidence interval: 1.7, 2.7 from logistic regression on individuals; odds ratio = 3.0, 95% confidence interval: 1.7, 5.3 from conditional logistic regression on twin pairs discordant for life dissatisfaction), whereas life dissatisfaction did not consistently predict poor sleep. There was substantial heritability for both traits, but their shared genetic component was relatively weak, as indicated by genetic correlations of 0.21 for men and 0.27 for women in a multivariate genetic model. This finding is consistent with the hypothesis that poor sleep may have direct effects on the brain, emotions, and mood.

NAPSAQ-1: National Patient Sleep Assessment Questionnaire in depression

Objectives. Sleep disturbance is a common feature of depression. Symptoms often persist after treatment of the depressive episode, representing a risk factor for relapse. There is a lack of data regarding the nature of sleep disturbance in depression in the UK. Methods. We surveyed patients' views about their depressive symptoms and associated sleep difficulties. We received 513 responses via postal questionnaire. Results. A total of 97% reported sleep difficulties during depression: symptoms of insomnia were more frequently reported than hypersomnia. Ninety-nine percent of those with sleep problems also reported daytime symptoms including lack of concentration, exhaustion and lethargy, no energy and feeling sleepy; 40% admitted napping during the day; 59% indicated that poor sleep greatly affected their quality of life (QOL); 34% considered it to be "very distressing"; 69% of respondents were taking antidepressant medication at the time (44% said it improved their sleep, 56% said it had no effect or worsened their sleep); 69% had sought extra treatment for their sleep problems. Conclusions. Sleep disturbance in depression is a common and distressing problem that seems relatively unresolved by treatment. There is a need for more successful management in order to improve QOL in these patients and reduce a factor in depressive relapse.

Core symptoms of major depressive disorder: relevance to diagnosis and treatment

The construct of major depressive disorder makes no etiological assumptions about populations with diverse symptom clusters. "Depressed mood" and "loss of interest or pleasure in nearly all activities" are core features of major depressive episode, though a strong case can be made to pay increasing attention to symptoms of fatigue, sleep disturbance, anxiety, and neurocognitive and sexual dysfunction in the diagnosis and evaluation of treatment outcome. Mood, guilt, work, and interest, as well as psychic anxiety, are consistently identified across validated subscales of the Hamilton Depression Rating Scale as prevalent and sensitive to change with existing treatments. A major limitation of these antidepressant therapies is their narrow spectrum of action. While the core "mood and interest" symptoms have been the main focus of attention, the associated symptoms listed above are often unaffected or exacerbated by current treatments. Careful clinical evaluation should address all of these dimensions, recognizing that improvement may occur sooner in some symptoms (eg, mood) compared with others (eg, sleep disturbance).

Attachment styles and sleep measures in a community-based sample of older adults

BACKGROUND

Measures of attachment style are often used to appraise social and emotional health. In developmental literature, the concept of attachment is used to explain relationships between children and their adult caregivers. While both attachment styles and sleep patterns are conceived as developmentally organized systems, very few studies have explored the link between the two. The present study examined whether attachment styles and sleep measures are associated among older adults.

METHODS

Relationships between attachment styles (i.e., secure, fearful, preoccupied, and dismissive) and subjective sleep measures were assessed utilizing data from 70 older participants (mean age: 68+/-6 years; Blacks: 59% and Whites: 41%) in a community-based study assessing subjective health characteristics. After obtaining informed consent, each participant provided demographic and socioeconomic data, as well as relevant medical and subjective data.

RESULTS

Independent of participants' demographic and subjective factors, significant correlations were found between the preoccupied attachment dimension and sleep measures. Specifically, individuals scoring high on the preoccupied attachment dimension were more likely to report daytime napping (r(p)=0.31, p<0.01) and to use sleep-inducing medications (r(p)=0.37, p<0.05). No significant correlations were found among sleep measures and the secure, dismissive, and fearful dimensions.

CONCLUSIONS

Important relations have been observed between specific attachment styles and subjective sleep factors in our data. Although only one-dimension (preoccupied) demonstrated statistical significance, a trend was observed, suggesting possible associations between the secure attachment style dimension and subjective sleep measures. Future studies are needed to broaden our understanding of the relationship between attachment styles and sleep patterns.

Prognosis of fatigue and functioning in primary care: a 1-year follow-up study

PURPOSE

Although fatigue is a common presenting symptom in primary care and its course and outcomes often remain unclear, cohort studies among patients seeking care for fatigue are scarce. We therefore aimed to investigate patterns in the course of fatigue and relevant secondary outcomes in a large cohort of patients who sought care for a main symptom of fatigue.

METHODS

We performed an observational cohort study in 147 primary care practices. Patients consulting their general practitioner for a new episode of fatigue were sent questionnaires at 1, 4, 8, and 12 months after baseline. We collected measures of fatigue, perceived health and functioning, absenteeism, psychological symptoms, and sleep using the Checklist Individual Strength, the 36-Item Short Form Health Survey, the Four-Dimensional Symptoms Questionnaire, and the Pittsburgh Sleep Questionnaire Inventory. Patients were classified into 4 subgroups based on fatigue severity scores over time. We assessed patterns in the course of all outcomes in these subgroups and in the total population, and tested changes over time and differences between subgroups.

RESULTS

A total of 642 patients were enrolled in the study. Response rates during follow-up ranged between 82% and 88%. For 75% of the patients, 4 distinct groups could be discerned: 26% of patients had continuously high scores for fatigue, 17% had a fast recovery, 25% had a slow recovery, and 32% initially improved but then had a recurrence of fatigue. Patterns for the secondary outcomes of symptoms and functioning were all similar to the pattern for fatigue within each of the subgroups.

CONCLUSIONS

The findings of this study suggest a longitudinal relationship between the severity of fatigue, impaired functioning, psychological symptoms, and poor sleep. Physicians should be aware that a substantial proportion of patients seeking care for fatigue have these additional health and psychosocial problems.

The circadian basis of mood disorders: recent developments and treatment implications

In humans, most physiological and behavioural functions demonstrate a circadian rhythmicity, which is essential to adequately cope with dramatic fluctuations occurring in the external environment. Therefore, it is intuitive that alterations in the endogenous machinery regulating circadian oscillations may lead to physical and mental symptoms and morbidities. Mood disorders, especially unipolar depression and seasonal affective disorder, have been linked to circadian rhythm abnormalities. This paper provides a brief description of the molecular and genetic mechanisms regulating the endogenous clock system and reviews selected studies describing circadian abnormalities in patients with depression. Evidence is emerging that a disruption of the normal circadian rhythmicity occurs at least in a subgroup of depressed patients and that interventions able to resynchronize the human circadian system, including sleep deprivation, light therapy and drugs specifically acting on the endogenous clock system, have proven antidepressant effects. It seems likely that, in the future, the knowledge coming from the exploration of molecular and genetic mechanisms involved in the physiology of the circadian clock system will be fruitful for a deeper understanding of the etiopathogenesis of mood disorders and the development of more effective therapeutic strategies.

Circadian rhythm disturbances in depression

OBJECTIVE

The aim of this article is to review progress in understanding the mechanisms that underlie circadian and sleep rhythms, and their role in the pathogenesis and treatment of depression.

METHODS

Literature was selected principally by Medline searches, and additional reports were identified based on ongoing research activities in the authors' laboratory.

RESULTS

Many physiological processes show circadian rhythms of activity. Sleep and waking are the most obvious circadian rhythms in mammals. There is considerable evidence that circadian and sleep disturbances are important in the pathophysiology of mood disorders. Depressed patients often show altered circadian rhythms, sleep disturbances, and diurnal mood variation. Chronotherapies, including bright light exposure, sleep deprivation, and social rhythm therapies, may be useful adjuncts in non-seasonal and seasonal depression. Antidepressant drugs have marked effects on circadian processes and sleep.

CONCLUSIONS

Recent progress in understanding chronobiological and sleep regulation mechanisms may provide novel insights and avenues into the development of new pharmacological and behavioral treatment strategies for mood disorders.

Outcomes in major depressive disorder: the evolving concept of remission and its implications for treatment

It is increasingly recognised that major depressive disorder can be a chronic condition with many patients experiencing recurrent episodes. Remission from a depressive episode implies the absence or near absence of depressive symptoms. However, for many patients the periods between depressive episodes are not symptom free. Residual symptoms are predictors of relapse or recurrence, and may be associated with residual psychosocial impairment. In clinical studies, remission is commonly defined using a cut-off score on a rating scale for depressive symptoms, such as a score of < or = 7 on the 17-item Hamilton scale. However, there is debate about which scales and cut-offs are optimal and full-length rating scales are not widely used in clinical practice. In spite of such issues, it seems clear that a therapy should aim at the most complete remission possible. Unfortunately, recent studies have highlighted that in clinical practice usually only a low rate of remission is achieved. Although long-term treatment with antidepressants can reduce the risk of relapse or recurrence only a minority of patients in clinical practice achieve this as treatment is often prematurely stopped due to long-term side effects such as sleep disturbance, sexual dysfunctioning and weight gain. Therefore, it represents an unmet need to come up with antidepressant drugs of greater efficacy and improved tolerability as such treatments could lead to more complete remission in more patients.

Negative affect and anger rumination as mediators between forgiveness and sleep quality

Research indicates that forgiveness of interpersonal transgressions relates to better sleep quality, whereas maintaining feelings of anger and hostility relates to poorer sleep quality. However, the mechanisms explaining these relationships have yet to be determined. We examined whether negative affect and anger rumination mediate the relationship between forgiveness of others and sleep quality using a sample of 277 undergraduates from a medium-sized Midwestern Catholic university. Participants completed self-report questionnaires assessing forgiveness of others (situational and dispositional), sleep quality (nocturnal sleep and daytime fatigue), negative affect (depression and anxiety), and anger rumination. Using structural equation modeling, we found that negative affect and anger rumination mediated the relationship between forgiveness and sleep quality through two indirect pathways. In one pathway, negative affect mediated between forgiveness and sleep quality. In the second pathway, both negative affect and anger rumination functioned as mediators. Implications for clinicians and researchers are discussed.

The Relationship Between Reported Problems Falling Asleep and Cognition Among African American Elderly

This study examined the relationship between elders' cognitive performance and self-reported trouble falling asleep. Analyses were conducted on 174 older independently living, community dwelling African Americans ( M age = 72.74; range = 65 to 90). Cognitive performance was measured using the Mini-Mental State Examination, Forward Digit Span task, Backward Digit Span task, Alpha Span task, and California Verbal Learning Test. Results suggested that individuals who reported trouble falling asleep tended to perform significantly worse than individuals who did not report trouble falling asleep on measures tapping short-term memory and working memory after controlling for age, education, gender, depression, and current health. These results demonstrate that a self-report of sleep difficulty may be a unique predictor of cognitive performance.

Decrease in REM latency and changes in sleep quality parallel serotonergic damage and recovery after MDMA: a longitudinal study over 180 days

The recreational drug ecstasy [3,4-methylenedioxymethamphetamine (MDMA)], has been found to selectively damage brain serotonin neurons in experimental animals, and probably in human MDMA users, but detailed morphometric analyses and parallel functional measures during damage and recovery are missing. Since there is evidence that serotonin regulates sleep, we have compared serotonergic markers parallel with detailed analysis of sleep patterns at three time-points within 180 d after a single dose of 15 mg/kg MDMA in male Dark Agouti rats. At 7 d and 21 d after MDMA treatment, significant(30-40%), widespread reductions in serotonin transporter (5-HTT) density were detected in the cerebral cortex, hippocampus, most parts of the hypothalamus, and some of the brainstem nuclei. With the exception of the hippocampus, general recovery was observed in the brain 180 d after treatment. Transient increases followed by decreases were detected in 5-HTT mRNA expression of dorsal and median raphe nuclei at 7 d and 21 d after the treatment. Significant reductions in rapid eye movement (REM) sleep latency, increases in delta power spectra in non-rapid eye movement sleep and increased fragmentation of sleep were also detected, but all these alterations disappeared by the 180th day. The present data provide evidence for long-term, albeit, except for the hippocampus, transient changes in the terminal and cellular regions of the serotonergic system after this drug. Reduced REM latency and increased sleep fragmentation are the most characteristic alterations of sleep consistently described in depression using EEG sleep polygraphy.

Declarative and procedural memory consolidation during sleep in patients with borderline personality disorder

Borderline personality disorder (BPD) is characterized by changes in subjective and objective measures of sleep quality. As recent findings point to the importance of sleep in memory consolidation, sleep-related memory consolidation was investigated in 15 female BPD patients (mean age 26.1+/-6.1 years) and 15 female healthy controls (mean age 25.6+/-6.8 years). Before and after the study night, declarative and procedural memory performance was tested by a paired associate list and a mirror tracing task. Subjective sleep quality was assessed by a sleep questionnaire, objective sleep quality was measured by a portable sleep recording device. During the study night the restorative value of sleep was significantly reduced in BPD patients (p<0.001), while objective sleep quality showed a trend for longer REM sleep duration (p=0.054). No significant differences were found regarding overnight performance improvement in the declarative and procedural memory tasks. Present findings suggest that declarative and procedural memory consolidation during sleep is intact in BPD patients.

Poor sleep quality and changes in objectively recorded sleep after traumatic brain injury: a preliminary study

OBJECTIVES

To evaluate changes in sleep quality and objectively assessed sleep parameters after traumatic brain injury (TBI) and to investigate the relationship between such changes and mood state and injury characteristics.

DESIGN

Survey and laboratory-based nocturnal polysomnography.

SETTING

Sleep laboratory.

PARTICIPANTS

Ten community-based subjects with moderate to very severe TBI and 10 age- and sex-matched controls from the general community.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Pittsburgh Sleep Quality Index for self-report sleep quality, nocturnal polysomnography for objective sleep recording, and Hospital Anxiety and Depression Scales.

RESULTS

Compared with controls, TBI patients reported significantly poorer sleep quality and higher levels of anxiety and depression. Objective sleep recording showed that TBI patients showed an increase in deep (slow wave) sleep, a reduction in rapid eye movement sleep, and more frequent nighttime awakenings. No significant relationship was observed between these changes in sleep and injury severity or time since injury. Anxiety and depression covaried with the observed changes in sleep.

CONCLUSIONS

The findings contribute to the growing body of evidence that sleep is involved in the physiologic processes underlying neural recovery. The association between anxiety and depression and the observed changes in sleep in TBI patients warrants further examination to determine whether a causative relationship exists.

A bidirectional relationship between anxiety and depression, and insomnia? A prospective study in the general population

OBJECTIVE

The purpose of this study was to examine whether there is a bidirectional relationship between, on one hand, anxiety and depression and, on the other hand, insomnia over the course of a year.

METHODS

A randomly selected sample of 3000 participants from the general population filled out a baseline survey (N=1812) and a 1-year follow-up survey (N=1498) on anxiety, depression, and insomnia.

RESULTS

On cross-sectional analyses, bivariate correlations showed that anxiety, depression, and insomnia were significantly intercorrelated (varphi=.31-.54). On prospective analyses, logistic regression analyses demonstrated that anxiety at baseline [odds ratio (OR)=4.27 (8% of variance)] and depression at baseline [OR=2.28 (2% of variance)] were related to new cases of insomnia on follow-up. Furthermore, insomnia at baseline was related to new episodes of high anxiety and high depression on follow-up [OR=2.30 (2% of variance) and OR=3.51 (4% of variance), respectively].

CONCLUSION

Evidence suggests that there is a bidirectional relationship between, on one hand, anxiety and depression and, on the other hand, insomnia. This suggests that anxiety, depression, and insomnia are intertwined over time, implying implications for theoretical conceptualizations and interventions.

Assessment and treatment for insomnia and fatigue in the symptomatic menopausal woman with psychiatric comorbidity

Studies and treatments for the symptomatic menopausal woman with sleep complaints have been reviewed elsewhere. This article, as part of the clinical review series on the comorbid symptomatic menopausal woman, aims to examine the evidence for diagnosis and treatment of women who present with distressing sleep symptoms that they attribute to menopause. The etiology of these symptoms may be a psychiatric disorder, a pre- or co-existing problem with sleep, or a dynamic interaction among one of these and/or a symptomatic menopause. The relationship between sleep disturbance and cognitive complaints, mood problems, fatigue and low energy will be reviewed. The new research on sleep, clinical consequences of insomnia of various types, the impact of sleep disturbance on morbidity and functioning--in the context of the midlife woman in the menopausal transition--will be explored along with the evidence for different treatment strategies for these sleep problems.

Qualidade do sono e depressão: que relações sintomáticas em crianças de idade escolar

O sono e a depressão têm sido associados, tendo-se questionado se um padrão de sono deficitário era condição necessária e suficiente para o aparecimento de sintomatologia depressiva. Este estudo procura averiguar a prevalência dos problemas de sono e da depressão em crianças em idade escolar. Foram avaliadas em dois momentos 467 crianças da escola primária, com idades compreendidas entre os 6 e os 11 anos de idade (M=8,70; DP=0,692). Os resultados revelam uma diminuição na prevalência ao longo do ano lectivo nos dois quadros nosológicos, verificando-se também uma relação negativa entre o rendimento académico e a sintomatologia depressiva nos dois momentos de avaliação (T1 rho=-0,349; p=0,000; T2 rho=-0,406; p=0,000). Serão discutidas implicação dos resultados para a avaliação e intervenção das crianças, contemplando a possibilidade de uma intervenção precoce de modo a prevenir o aparecimento de um estado depressivo na infância que venha manter ou agravar os problemas do sono.

Qualidade subjetiva do sono em pacientes com transtorno depressivo

O objetivo deste estudo foi avaliar a qualidade subjetiva do sono em pacientes com transtorno depressivo. Setenta pacientes (44 mulheres e 26 homens) ambulatoriais com diagnóstico de transtorno depressivo foram entrevistados e responderam ao Índice de Qualidade de Sono de Pittsburgh (IQSP), ao Questionário de Hábitos do Sono e ao Inventário de Depressão de Beck (BDI). As médias das pontuações globais do IQSP e BDI foram respectivamente 12,80 ± 3,77 e 35,83 ± 8,85, e a correlação foi positiva e significativa entre essas escalas (r = 0,70; p < 0,05). As pontuações globais do IQSP em pacientes com insônia (16,61 ± 4,21) e hipersonia (8,82 ± 2,71) apresentaram diferenças marcantes (p < 0,05). Os resultados da análise multivariada indicaram que apenas a insônia foi significativamente associada à qualidade subjetiva do sono (RC = 4,1; 95% IC = 2,0-4,2). Os resultados sugerem que os pacientes da amostra apresentaram percepção inferior da qualidade subjetiva do sono, principalmente na insônia.

Sleep disorders and suicidal ideation in patients with depressive disorder

An intrinsic association between suicidal ideation and sleep disorders in patients with depressive disorder has been observed in recent studies. This study was conducted in order to examine the relationship between suicidal ideation and sleep disorders, such as insomnia and excessive sleepiness, in outpatients with major depressive disorder. Seventy patients with diagnoses of major depressive disorder were interviewed and assessed with the Sleep Habits Questionnaire and the Beck Scale for Suicidal Ideation (SSI). Data analyses were performed through descriptive analysis, Students t-test, Chi-square test and logistic regression model, with a statistical significance of 5%. In this study, depressed patients had high SSI scores (6.12+/-2.67), particularly for active suicidal ideation (1.61+/-0.39) and specific plans for suicide components (1.51+/-0.40). Depressed patients with insomnia had significantly higher SSI scores (7.39+/-2.84), in relation to patients with excessive sleepiness (3.68+/-1.73). Furthermore it was observed that insomniac patients had significantly higher scores on the following components: active suicide ideation, specific plans for suicide and previous suicide attempts. The results of multivariate analysis showed that only insomnia had a significant association with suicidal ideation. Thus, sleep disturbances, particularly insomnia, should be considered in the assessment of suicidal risk in outpatients with depressive disorder.

Effects of rapid eye movement sleep deprivation on hypocretin neurons in the hypothalamus of a rat model of depression

Hypocretin (Hcrt, also known as orexin) is a hypothalamic neuropeptide linked to narcolepsy, a disorder diagnosed by the appearance of rapid eye-movement sleep (REMS)-state characteristics during waking. Major targets of Hcrt-containing fibers include the locus coeruleus and the raphe nucleus, areas with important roles in regulation of mood and sleep. A relationship between REMS and mood is suggested by studies demonstrating that REMS-deprivation (REMSD) ameliorates depressive symptoms in humans. Additional support is found in animal studies where antidepressants and REMSD have similar effects on monoamiergic systems thought to be involved in major depression. Recently, we have reported that Wistar-Kyoto (WKY) rats, an animal model of depression, have reduced number and size of hypothalamic cells expressing Hcrt-immunoractivity compared to the parent, Wistar (WIS) strain, suggesting the possibility that the depressive-like attributes of the WKY rat may be determined by this relative reduction in Hcrt cells [Allard, J.S., Tizabi, Y., Shaffery, J.P., Trouth, C.O., Manaye, K., 2004. Stereological analysis of the hypothalamic hypocretin/orexin neurons in an animal model of depression. Neuropeptides 38, 311-315]. In this study, we sought to test the hypothesis that REMSD would result in a greater increase in the number and/or size of hypothalamic, Hcrt-immunoreactive (Hcrt-ir) neurons in WKY, compared to WIS rats. The effect of REMSD, using the multiple-small-platforms-over-water (SPRD) method, on size and number of Hcrt-ir cells were compared within and across strains of rats that experienced multiple-large-platforms-over-water (LPC) as well as to those in a normal, home-cage-control (CC) setting. In accord with previous findings, the number of Hcrt-ir cells was larger in all three WIS groups compared to the respective WKY groups. REMSD produced a 20% increase (p<0.02) in the number of hypothalamic Hcrt-ir neurons in WKY rats compared to cage control WKY (WKY-CC) animals. However, an unexpected higher increase in number of Hcrt-ir cells was also observed in the WKY-LPC group compared to both WKY-CC (31%, p<0.001) and WKY-SPRD (20%, p<0.002) rats. A similar, smaller, but non-significant, pattern of change was noted in WIS-LPC group. Overall the data indicate a differential response to environmental manipulations where WKY rats appear to be more reactive than WIS rats. Moreover, the findings do not support direct antidepressant-like activity for REMSD on hypothalamic Hcrt neurons in WKY rats.