Electroencephalographic sleep profiles in single-episode and recurrent unipolar forms of major depression: I. Comparison during acute depressive states

Sleep-wake profiles predict longitudinal changes in manic symptoms and memory in young people with mood disorders

Mood disorders are characterized by disabling symptoms and cognitive difficulties which may vary in intensity throughout the course of the illness. Sleep-wake cycles and circadian rhythms influence emotional regulation and cognitive functions. However, the relationships between the sleep-wake disturbances experienced commonly by people with mood disorders and the longitudinal changes in their clinical and cognitive profile are not well characterized. This study investigated associations between initial sleep-wake patterns and longitudinal changes in mood symptoms and cognitive functions in 50 young people (aged 13-33 years) with depression or bipolar disorder. Data were based on actigraphy monitoring conducted over approximately 2 weeks and clinical and neuropsychological assessment. As part of a longitudinal cohort study, these assessments were repeated after a mean follow-up interval of 18.9 months. No significant differences in longitudinal clinical changes were found between the participants with depression and those with bipolar disorder. Lower sleep efficiency was predictive of longitudinal worsening in manic symptoms (P = 0.007). Shorter total sleep time (P = 0.043) and poorer circadian rhythmicity (P = 0.045) were predictive of worsening in verbal memory. These findings suggest that some sleep-wake and circadian disturbances in young people with mood disorders may be associated with less favourable longitudinal outcomes, notably for subsequent manic symptoms and memory difficulties.

[The specificity of cognitive reactivity in recurrent major depressive episodes]

The present study examined cognitive vulnerability to relapses of depression by clarifying the characteristics of "cognitive reactivity" in people with recurrent major depressive episodes. Study 1-1 and 1-2 developed a Japanese version of the Leiden Index of Depression Sensitivity-Revised (LEIDS-R), which assessed cognitive reactivity, and evaluated the reliability and validity of the scale. Study 2 examined the characteristics of cognitive reactivity which differentiate people with recurrent major depressive episodes from people with a single episode or none. The Japanese version of the LEIDS-R was shown to have reasonable reliability and validity. Participants with recurrent major depressive episodes showed more repetitive thoughts about negative issues and avoidance from internal and external aversive events when depressive mood was induced, compared to participants with only a single episode of depression. These results suggest that the characteristics of cognitive reactivity are important considerations for preventing relapse of depression.

Selectively bred rodents as models of depression and anxiety

Stress related diseases such as depression and anxiety have a high degree of co morbidity, and represent one of the greatest therapeutic challenges for the twenty-first century. The present chapter will summarize existing rodent models for research in psychiatry, mimicking depression- and anxiety-related diseases. In particular we will highlight the use of selective breeding of rodents for extremes in stress-related behavior. We will summarize major behavioral, neuroendocrine and neuronal parameters, and pharmacological interventions, assessed in great detail in two rat model systems: The Flinders Sensitive and Flinders Resistant Line rats (FSL/FRL model), and rats selectively bred for high (HAB) or low (LAB) anxiety related behavior (HAB/LAB model). Selectively bred rodents also provide an excellent tool in order to study gene and environment interactions. Although it is generally accepted that genes and environmental factors determine the etiology of mental disorders, precise information is limited: How rigid is the genetic disposition? How do genetic, prenatal and postnatal influences interact to shape adult disease? Does the genetic predisposition determine the vulnerability to prenatal and postnatal or adult stressors? In combination with modern neurobiological methods, these models are important to elucidate the etiology and pathophysiology of anxiety and affective disorders, and to assist in the development of new treatment paradigms.

Clinical relevance of disturbances of sleep and vigilance in major depressive disorder: a review

OBJECTIVE

The primary objective of this article is to provide a concise review of the clinical relevance of sleep and vigilance in major depressive disorder.

DATA SOURCES

PubMed was reviewed (1990-2009) and English-language articles were identified using the key words sleep and depression and sleep and antidepressants. Secondary searches included articles cited in sources identified by the primary search.

STUDY SELECTION

The narrative review provides brief descriptions of the normal physiology of sleep and changes associated with depression, as well as the impact of various treatments on these processes.

DATA SYNTHESIS

Although it has long been known that sleep disturbances are an important characteristic of depression, relatively few studies have been conducted with the newer-generation antidepressants. Neither of the most widely used classes of antidepressants, the selective serotonin reuptake inhibitors and the serotonin-norepinephrine reuptake inhibitors, have particularly beneficial effects on sleep and, among the medications that reliably improve sleep efficiency, including mirtazapine and the tricyclic antidepressants, problems with daytime sedation can offset therapeutic benefit. Despite relatively widespread use, trazodone has not been demonstrated to be an effective and safe hypnotic in patients taking other antidepressants. For many patients, ongoing concomitant treatment with benzodiazepines and related drugs is the preferred option, again without convincing empirical support of longer-term efficacy. Among newer and investigational antidepressants, agomelatine shows promise with respect to both overall safety and effects on insomnia, although possible negative effects on liver function warrant further study.

CONCLUSIONS

Sleep disturbances are a significant aspect of depressive syndromes, and relief of insomnia remains an important unmet need in antidepressant therapeutics. Development of a well-tolerated antidepressant medication that rapidly improves sleep maintenance without daytime sedation is a priority for drug development.

History of depressive episodes as a risk factor for illness severity in early inflammatory arthritis

OBJECTIVE

Psychosocial research in arthritis consistently demonstrates a relationship between depression and disease characteristics such as severity of illness and physical disability. In this study, we examine how a history of clinical depression identified through diagnostic interviews influences disease outcome measures in patients with early inflammatory arthritis (EIA) in the absence of current depression.

METHODS

Patients in the early phase (more than 6-weeks, less than 1-year duration) of inflammatory arthritis were recruited from a larger EIA registry, which recorded sociodemographic data, current depressive symptoms and measures of disease severity. Current and history of major depression was assessed by a structured clinical interview. Eighty-one patients without current major depression were divided into two groups: 28 with and 53 without a history of depression.

RESULTS

There were no significant differences between the two groups in age, sex, education, income, or level of current depressive symptoms. Compared with patients with no history of major depression, those with a history of depressive episodes had higher self-ratings of disease activity and were assessed as having more severe disease and poorer physical functioning by their physicians.

CONCLUSION

This study indicates that a history of major depression represents a risk factor for disease severity in EIA. This may reflect an enduring physiological effect of depression that influences subsequent inflammatory arthritis or an underlying shared process between these two disease entities.

Wake and sleep EEG provide biomarkers in depression

Both wake and sleep electroencephalogram (EEG) provide biomarkers of depression and antidepressive therapy, respectively. For a long time it is known that EEG activity is altered by drugs. Quantitative EEG analysis helps to delineate effects of antidepressants on brain activity. Cordance is an EEG measure with a superior correlation with regional brain perfusion. Prefrontal quantitative EEG cordance appears to be a predictor of the response to antidepressants. Sleep EEG shows characteristic changes in depression as impaired sleep continuity, desinhibition of REM sleep and changes of nonREM sleep. Elevated REM density (a measure for frequency of rapid eye movements) characterizes an endophenotype in family studies of depression. REM-sleep changes including a more distinct REM rebound after sleep deprivation are found in animal models of depression. Most antidepressants suppress REM sleep in depressed patients, normal controls and laboratory animals. REM suppression appears to be a distinct, but not an absolute requirement for antidepressive effects of a compound. Sleep-EEG variables like REM latency or certain clusters of variables were shown to predict the response to the treatment with a certain antidepressant or even the course of the disorder for several years. Some of these predictive sleep-EEG markers of the longterm course of depression appear to be closely related to hypothalamo-pituitary-adrenocortical system activity.

Autonomous and controlled motivation and interpersonal therapy for depression: moderating role of recurrent depression

OBJECTIVES

We examined the moderating role of depression recurrence on the relation between autonomous and controlled motivation and interpersonal therapy (IPT) treatment outcome.

DESIGN

The investigation was conducted in an out-patient mood disorders clinic of a large university-affiliated psychiatric hospital. The sample represents a subset of a larger naturalistic database of patients seen in the clinic.

METHODS

We examined 74 depressed out-patients who received 16 sessions of IPT. The Beck Depression Inventory-II, administered at pre-treatment and post-treatment, served as a measure of depressive severity. Measures of motivation and therapeutic alliance were collected at the third session.

RESULTS

In the entire sample, both the therapeutic alliance and autonomous motivation predicted higher probability of achieving remission; however, the relation differed for those with highly recurrent depression compared to those with less recurrent depression. For those with highly recurrent depression, the therapeutic alliance predicted remission whereas autonomous motivation had no effect on remission. For those with less recurrent depression, both autonomous motivation and the therapeutic alliance predicted better achieving remission. Controlled motivation emerged as a significant negative predictor of remission across both groups.

CONCLUSION

Taken together, these results highlight the possible use of motivation theory to inform and enrich therapeutic conceptualizations and interventions in clinical practice, but also point to the importance of modifying interventions based on the chronicity of a client's depression.

Elevated serotonin 1A binding in remitted major depressive disorder: evidence for a trait biological abnormality

Several biological abnormalities in major depressive disorder (MDD) persist during episode remission, including altered serotonin neurotransmission, and may reflect underlying pathophysiology. We previously described elevated brain serotonin 1A (5-HT(1A)) receptor binding in antidepressant-naive (AN) subjects with MDD within a major depressive episode (MDE) compared with that in healthy controls using positron emission tomography (PET). In this study, we measured 5-HT(1A) receptor binding in unmedicated subjects with MDD during sustained remission, hypothesizing higher binding compared with that in healthy controls, and binding comparable with currently depressed AN subjects, indicative of a biological trait. We compared 5-HT(1A) binding potential (BP(F)) assessed through PET scanning with [(11)C]WAY-100635 in 15 subjects with recurrent MDD in remission for >or=12 months and off antidepressant medication for >or=6 months, 51 healthy controls, and 13 AN MDD subjects in a current MDE. Metabolite-corrected arterial input functions were acquired for the estimation of BP(F). Remitted depressed subjects had higher 5-HT(1A) BP(F) compared with healthy controls; this group difference did not vary significantly in magnitude across brain regions. 5-HT(1A) BP(F) was comparable in remitted and currently depressed subjects. Elevated 5-HT(1A) BP(F) level among subjects with remitted MDD appears to be a trait abnormality in MDD, which may underlie recurrent MDEs. Future studies should evaluate the role of genetic and environmental factors in producing elevated 5-HT(1A) BP(F) and MDD, and should examine whether 5-HT(1A) BP(F) is a vulnerability factor to MDEs that could have a role in screening high-risk populations for MDD.

Acute tryptophan depletion evokes negative mood in healthy females who have previously experienced concurrent negative mood and tryptophan depletion

INTRODUCTION

The majority of individuals who suffer an episode of depression go on to experience recurrences. We have proposed, based upon the observation that reducing serotonin via acute tryptophan depletion (ATD) is more likely to induce negative mood in recovered depressed individuals than never depressed individuals, that this may be because associations form between negative mood and reduced serotonin during an episode of depression (Robinson and Sahakian, Psychol Med 38:315-318, 2008b). Such associations would mean that subsequent reductions in serotonin are more likely to provoke depressed mood and hence trigger an episode of depression.

METHODS

In this study, we tested this hypothesis by manipulating the mood state of healthy females undergoing ATD (or balanced placebo) on two separate testing sessions. On the first session, subjects received either negative or neutral mood induction, while on the second session all subjects received neutral mood induction.

RESULTS

Our findings demonstrate significant ATD-induced negative mood exclusively on the second visit of subjects who received both ATD and negative mood induction procedure on their first visit.

DISCUSSION

These findings may be explained by the formation of an association between the negative mood and reduced serotonin states during the first visit. As such, these findings provide preliminary support for the associative hypothesis of recurrence in depression.

CONCLUSION

Such associations might therefore explain the discrepancy between the effects of ATD in recovered- and never-depressed individuals and may, in turn, explain why an episode of depression increases the risk of subsequent episodes.

Risk markers for depression in adolescents: sleep and HPA measures

Previous work has demonstrated reliable electroencephalographic (EEG) sleep and hypothalamic-pituitary-adrenal (HPA) changes associated with adult major depressive disorder. These changes might be evident before clinical manifestation of the illness in at-risk persons. The aim of the study was to identify depression-related EEG sleep and HPA changes in healthy adolescents at high risk for depression, and to examine the relationship between EEG sleep (or HPA) changes and the onset of depression. Forty-eight adolescent volunteers with no personal history of a psychiatric illness, including depression, but who were at high risk for developing depression by virtue of parental depression (high-risk group), and 48 adolescent volunteers with no personal or family history of a psychiatric disorder (normal controls) were recruited. EEG sleep and HPA measures were collected on three consecutive evenings and nights at baseline. Clinical follow-up evaluations were conducted at regular intervals over a 5-year period. Compared with normal controls, adolescents at high risk for depression had shorter latency to rapid eye movement (REM) sleep, increased phasic REM sleep, more REM sleep and elevated nocturnal urinary-free cortisol (NUFC) excretion at baseline. Shorter REM latency, higher REM density and elevated NUFC (measured at baseline) were associated with the development of depression during follow-up. The findings that REM sleep abnormalities and elevated HPA activity occur before the onset of depression in at-risk adolescents suggest that these variables serve as vulnerability markers for the illness.

Electroencephalographic sleep and hypothalamic-pituitary-adrenal changes from episode to recovery in depressed adolescents

OBJECTIVE

The study examined electroencephalographic (EEG) sleep and hypothalamic-pituitary-adrenal (HPA) changes associated with depressive episode and during recovery in adolescent depression.

METHODS

Sixteen adolescents with major depressive disorder and 16 volunteers with no personal or family history of psychiatric disorder participated in a three-night EEG sleep protocol along with nocturnal urinary free cortisol (NUFC). Depressed subjects also were restudied during stable remission from the depressive episode.

RESULTS

Compared with controls, depressed adolescents had significantly reduced sleep efficiency, shorter latency to rapid eye movement (REM) sleep, increased phasic REM sleep, and elevated NUFC excretion. Among depressed subjects, EEG sleep values did not change significantly from episode to remission. NUFC excretion reduced significantly during remission from the depressive episode.

CONCLUSIONS

The findings that EEG sleep measures are independent of clinical state, whereas HPA variables are state dependent, suggest that sleep and HPA measures make a differential contribution to our understanding of the pathophysiology and prognosis of mood disorders in adolescent patients.

Recurrence in major depressive disorder: a neurocognitive perspective

Depressive disorders are amongst the leading causes of disability and mortality worldwide and, as such, it is predicted that by 2010 only cardio-ischaemic disorders will provide a greater burden. In addition to the sizable emotional, individual and social burden, depressive disorders cost an estimated US$83.1 billion per year in the United States alone. In spite of effective treatments, a large proportion of sufferers go on to experience recurrences. With successive recurrences, the likelihood of subsequent episodes increases. Despite this, research to date has tended to focus on first episodes or else has not distinguished between episodes. This editorial review highlights a number of differences between first and recurrent episodes which, in turn, recommend more longitudinal, recurrence-oriented, treatments. We also examine the findings from acute tryptophan depletion studies which, it is speculated, help to understand the differences between successive episodes. The overall aim, however, is to highlight the importance of recurrence in depression and to stimulate debate.

HPA axis and sleep: identifying subtypes of major depression

It is increasingly acknowledged that the diagnosis of major depression encompasses patients who do not necessarily share the same disease biology. Though the diagnostic criteria allow the specification of different subtypes, e.g. melancholic and atypical features, a consensus still has to be reached with regard to the clinical symptoms that clearly delineate these subtypes. Beside clinical characteristics, biological markers may help to further improve identification of biologically distinct endophenotypes and, ultimately, to devise more specific treatment strategies. Alterations of the hypothalamus-pituitary-adrenal (HPA) axis and sleep architecture are not only commonly observed in patients with major depression, but the nature and extent of these alterations can help to identify distinct subtypes. Thus, a HPA overdrive, due to enhanced secretion of corticotropin-releasing hormone (CRH) and an impaired negative feedback via glucocorticoid receptors, seems to be most consistently observed in patients with melancholic features. These patients also show the clearest sleep-electroencephalogram (EEG) alterations, including disrupted sleep, low amounts of slow wave sleep (SWS), a short rapid eye movement (REM) latency and a high REM density. In contrast, patients with atypical features are characterized by reduced activity of the HPA axis and ascending noradrenergic neurons in the locus coeruleus. Though sleep-EEG alterations have been less thoroughly examined in these patients, there are data to suggest that SWS is not reduced and that REM sleep parameters are not consistently altered. While the atypical and melancholic subtypes of major depression may represent the extremes of a spectrum, the distinct clinical features provide an opportunity to further explore biological markers, as well as environmental factors, contributing to these clinical phenotypes. Moreover, dysregulations of the HPA axis and sleep-EEG alterations can also be induced in rodents, thereby allowing alignment of critical biological aspects of a human disease subtype with an animal model. Such "Translational Research" efforts should help to develop targeted therapies for distinct patient populations.

Management of insomnia: treatments and mechanismsi

Management of insomnia is an interesting subject at present. New drug treatments are now becoming available after a relatively static period since the development of the Z-drugs in the 1990s. Moreover, more evidence is coming to light about the length of drug treatment and the effectiveness of psychological therapies. This article briefly describes current treatments, both evidence-based and common practice, and goes on to describe some emerging approaches.

Depression History, Stress, and Pain in Rheumatoid Arthritis Patients

This study examined the role of past episodes of depression on pain reports for patients with rheumatoid arthritis (RA) before and during stress induction. A history of major depressive episodes was assessed by diagnostic interviews for 138 RA patients, 74 who later participated in a set of laboratory procedures designed to induce interpersonal stress. Patients were evaluated by a rheumatologist and then asked to report joint and bodily pain throughout the laboratory study. We found that RA patients with a history of two or more episodes of major depression had more pain at baseline, and exhibited higher pain in response to the stress induction than did RA patients with either only one episode or no history of depression. Such findings provide new insight in the dynamic relationships between depression, stress, and pain.

Propagation of major depressive disorder: relationship between first episode symptoms and recurrence

Major depressive disorder is a highly recurrent disorder, with long-term estimates of recurrence ranging as high as 80%. The impact of first episode depressive symptoms on later recurrence has not been previously examined. The present study sought to identify risk factors for recurrent major depressive episodes by investigating first episode symptoms. It was predicted that the presence of depressed mood and sleep disturbance in the first episode would increase the likelihood of recurrence. Four hundred eighty-seven randomly selected community participants who met DSM-III-R criteria for at least one major depressive episode were assessed twice during adolescence and once in young adulthood. We examined the association between first major depressive episode symptoms and the presence of a recurrent episode. Recurrence was significant predicted by the presence of depressed mood and increased appetite at episode 1. A nonsignificant trend suggested that female gender may also be associated with recurrence. First episode depressed mood, increased appetite, and female gender may serve as specific risk factors for recurrence. The centrality of depressed mood to major depressive disorder is highlighted.

Sleep in patients with neurologic and psychiatric disorders

Given the widely recognized association between many neurologic and psychiatric disorders and significant sleep disturbances, the International Classification of Sleep Disorders Diagnostic and Coding Manual recognizes "Sleep Disorders Associated with Mental, Neurologic, or Other Medical Disorders" as one of four major classification categories. Such sleep disturbances may exacerbate symptoms of the underlying neurologic or psychiatric disorder or produce further adverse medical, behavioral, or psychosocial consequences. Therefore, adequate assessment and recognition of sleep disturbances in these populations is essential. This article includes a summary of neurologic systems influencing sleep that may be affected by neurologic and psychiatric disorders, followed by a brief review of sleep disturbances associated with many common neurologic and psychiatric disorders.

Electroencephalographic sleep profiles in treatment course and long-term outcome of major depression: association with DEX/CRH-test response

Altered electroencephalographic (EEG) sleep patterns are among the most prominent neurobiological findings in depression. Several of these alterations have been suggested to be associated with an unfavorable long-term outcome. However, the impact of pathological sleep parameters on a more recurrent course of illness or vice versa still warrants clarification. Underlying mechanisms may involve systems known to be related to both sleep regulation and long-term course of depression such as the hypothalamic-pituitary-adrenocortical (HPA) axis. Thus, EEG sleep profiles of patients with depression were examined to determine whether (1) the retrospective clinical course of depression, and (2) the prospective long-term outcome in follow-up are associated with EEG sleep parameters. To elucidate related mechanisms HPA system functioning was evaluated by using the combined DEX/CRH test. Fifteen patients with affective disorders who participated in an earlier controlled antidepressant treatment study over 6 weeks were consecutively enrolled in an exploratory follow-up study. The retrospective analysis revealed that during the acute state of depression predominantly sleep continuity measures were associated with the number of previously experienced episodes. While this relation disappeared during treatment and did not correlate with the prospective course, decreased slow wave sleep variables especially in the first sleep period and increased rapid eye movement density were predictive for the occurrence of recurrences in follow-up and, hence, probably reflect more trait-like markers. Additionally, EEG sleep variables unfavorable for long-term outcome were related to excessive stress hormone response in the DEX/CRH-test. These disturbances may reflect important mechanisms responsible of causing and maintaining the disease process of depression.

Emotional information processing in first and recurrent major depressive episodes

Depressive states are classically associated to increased sensitivity to negative events. However this hypersensitivity may not be stable in time, being absent in remission periods or further reinforced with recurrent depressive episodes, or may concern positive stimuli instead, e.g. in young depressive patients. To study the evolution of the processing of emotional information in depression we recorded late components of evoked potentials in first-episode and recurrent depressed patients before and after recovery. We used a visual attentional paradigm manipulating the processing of emotional information. Subjects first counted words with positive valence, and then words with negative valence from lists of usual words. The results showed that recurrent patients had increased P300 amplitudes for negative words selection only in negative words counting situation, while first-episode patients had decreased P300 amplitudes for positive words selection. After clinical improvement, the negative biases in recurrent patients group disappeared but P300 amplitudes of first-episode patients remained significantly low for positive words. First-episode depressed patients show a selective impairment for positive stimuli, with decreased response to pleasant stimuli, while recurrent depressive subjects show signs of hyperesthesia for negative stimuli. These results suggest that responses to emotional stimuli in word processing are related to the duration of the mood disorders.

Electroencephalographic sleep profiles in single-episode and recurrent unipolar forms of major depression: II. Comparison during remission

BACKGROUND

Previous studies indicate that recurrent forms of depression are associated with greater biological disturbances as compared to single-episode cases. This study examines whether the observed differences in the sleep patterns during recurrent and single-episode depression persist into remission following nonpharmacologic treatment.

METHODS

Two groups of patients (27 single episode [SE] and 53 recurrent unipolar [RU]) with major depression underwent sleep studies before and after nonpharmacologic treatment. Groups were equated for age, severity, and proportion of men and women. Groups were compared using multivariate analyses of covariance and/or analyses of covariance to examine six sets of sleep measures.

RESULTS

The differences observed between the SE and RU groups during the index episode persisted into early remission. The findings of greater disturbances of sleep continuity, rapid eye movement sleep and diminished slow wave sleep in the RU group supports the hypothesis that recurrent depression is associated with a more severe neurophysiological substrate than clinically comparable SE cases.

CONCLUSIONS

Although these observations are consistent with an illness progression model, the possibility that recurrent affective illness is associated with a more virulent, stable phenotype cannot be ruled out. Resolution of this issue requires longitudinal and family studies.

Treatment of insomnia in patients with mood disorders

Mood disorders and chronic insomnia share complex theoretical and clinical relationships. This article reviews the subjective symptoms and polysomnographic findings of subjects with mood and insomnia syndromes. The polysomnographic findings reviewed include macro-architectural and micro-architectural data. Various treatments of patients with insomnia and mood disorders will be presented, including both behavioral and pharmacological interventions.

Cognitive disturbance in outpatient depressed younger adults: evidence of modest impairment

BACKGROUND

Investigations of cognitive disturbances among patients with mood disorders have yielded inconsistent results. Although marked neuropsychologic deficits have been reported in elderly patients and in midlife patients with severe depression, the severity of cognitive impairments in medically healthy younger ambulatory adults with depression has not been well characterized.

METHODS

A comprehensive battery of standard neuropsychologic tests and experimental computerized measures of cognitive functioning were administered to unmedicated ambulatory younger adults with mild to moderate nonbipolar depression and to a group of age- and gender-equated healthy subjects.

RESULTS

Patients demonstrated a notable absence of widespread cognitive impairment. Deficits in executive functions were observed on the Wisconsin Card Sort Test but not on several other tests. Despite the absence of significant impairment on tests of attention, memory, and motor performance in the total sample, symptom severity and age of illness onset were correlated with poorer performance on some tests of cognitive functioning even after correction for age.

CONCLUSIONS

These findings, derived from a large sample of unmedicated depressed outpatients, indicate that major depressive disorder in healthy younger ambulatory adults does not cause appreciable impairments in cognitive functioning in the absence of clinical and course-of-illness features.

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

Disturbances of sleep are typical for most depressed patients and belong to the core symptoms of the disorder. Polysomnographic sleep research has demonstrated that besides disturbances of sleep continuity, in depression sleep is characterized by a reduction of slow wave sleep and a disinhibition of REM sleep, with a shortening of REM latency, a prolongation of the first REM period and increased REM density. These findings have stimulated many sleep studies in depressive patients and patients with other psychiatric disorders. In the meantime, several theoretical models, originating from basic research, have been developed to explain sleep abnormalities of depression, like the two-process-model of sleep and sleep regulation, the GRF/CRF imbalance model and the reciprocal interaction model of non-REM and REM sleep regulation. Interestingly, most of the effective antidepressant agents suppress REM sleep. Furthermore, manipulations of the sleep-wake cycle, like sleep deprivation or a phase advance of the sleep period, alleviate depressive symptoms. These data indicate a strong bi-directional relationship between sleep, sleep alterations and depression.

Are child-, adolescent-, and adult-onset depression one and the same disorder?

This paper reviews prior research studies examining neurobiological correlates and treatment response of depression in children, adolescents, and adults. Although there are some similarities in research findings observed across the life cycle, both children and adolescents have been found to differ from depressed adults on measures of basal cortisol secretion, corticotropin stimulation post-corticotropin releasing hormone (CRH) infusion, response to several serotonergic probes, immunity indices, and efficacy of tricyclic medications. These differences are proposed to be due to 1) developmental factors, 2) stage of illness factors (e.g., number of episodes, total duration of illness), or 3) heterogeneity in clinical outcome (e.g., recurrent unipolar course vs. new-onset bipolar disorder). Relevant clinical and preclinical studies that provide support for these alternate explanations of the discrepant findings are reviewed, and directions for future research are discussed. To determine whether child-, adolescent-, and adult-onset depression represent the same condition, it is recommended that researchers 1) use the same neuroimaging paradigms in child, adolescent, and adult depressed cohorts; 2) carefully characterize subjects' stage of illness; and 3) conduct longitudinal clinical and repeat neurobiological assessments of patients of different ages at various stages of illness. In addition, careful attention to familial subtypes (e.g., depressive spectrum disorders vs. familial pure depressive disorders) and environmental factors (e.g., trauma history) are suggested for future investigations.

Physiological effects of electroconvulsive therapy and transcranial magnetic stimulation in major depression

Major depressive episodes are associated with dysregulation of various physiologic systems. Antidepressant medications alter regulation of the hormonal and sleep systems. A thorough understanding of these changes may elucidate the pathophysiologic basis of the disorder [Amsterdam et al., 1989: Psychoneuroendocrinology 14:43-62], and interventions targeted directly at these systems are being increasingly recognized as possible treatments for depression [Wong et al., 2000: Proc Natl Acad Sci USA 97:325-330; Szuba et al., 1996: Proc Am Coll Neuropsychopharmacol Ann Meet]. These physiologic systems are regulated by the major neurotransmitters implicated in the etiology of mood disorders--norepinephrine, serotonin, and dopamine. Many of the hormones of import for this article also act as neurotransmitters and thus alter cerebral activity themselves [Owens and Nemeroff, 1993: Ciba Found Symp 172:296-308; Weitzner, 1998: Psychother Psychosom 67:125-132]. Parenteral infusion of hydrocortisone [DeBattista, 2000: Am J Psychiatry 157:1334-1337] and thyrotropin-releasing hormone (TRH) [Prange et al., 1972: Lancet 2:999-1002; Marangell et al., 1997: Arch Gen Psychiatry 54:214-222; Szuba, 1996: Proc Am Coll Neuropsychopharmacol Ann Meet.] produce acute antidepressant effects. Antagonists to corticotropin-releasing hormone and repeated parenteral infusion of TRH may have antidepressant activity when given during several weeks [Wong, 2000: Proc Natl Acad Sci USA 97:325-330; Arborelius et al., 1999: J Endocrinol 160:1-12; Callahan et al., 1997: Biol Psychiatry 41:264-272]. Manipulations of the sleep system through sleep deprivation can ameliorate depression [Szuba et al., 1994: Psychiatry Res 51:283-295; see Wirz-Justice et al., 1999: Biol Psychiatry 46:445-453 for review]. Sleep deprivation has been shown in more than three dozen studies published in the last three decades to produce marked, acute antidepressant effects in the majority of depressed individuals [Wirz-Justice, et al., 1999: Biol Psychiatry 46:445-453]. Thus, examination of the effects the two nonpharmacologic treatments, electroconvulsive therapy (ECT) and transcranial magnetic stimulation (TMS), produce in these physiologic systems may help elucidate their mechanisms of action, while enhancing understanding of the neurobiology of depressive illness. We will review these physiologic changes associated with depression, the effects that manipulations of these systems can have on depressive disorders, and then describe the effects the two techniques that can stimulate the human brain in vivo, ECT and TMS, exert on these systems.

Latent structure of EEG sleep variables in depressed and control subjects: descriptions and clinical correlates

In this study, we aimed to determine the latent structure of multiple EEG sleep variables in patients with major depressive disorder (MDD) and in healthy control subjects and to examine associations between sleep factors and clinical variables. Subjects included 109 women with MDD and 54 healthy control women. EEG sleep data were collected prior to any treatment. Principal components analysis (PCA) was conducted on a set of 24 sleep variables. Separate PCAs were run for patients with MDD, control subjects, and a matched group of patients and controls. Other analyses included correlations, t-tests and MANOVA. Each PCA identified four sleep factors that explained 70% of the total variance in individual sleep variables: slow wave sleep, REM sleep, sleep continuity and REM latency/delta sleep ratio (RL/DSR). Patients with MDD and healthy controls differed on the mean value of the sleep continuity factor, and a multivariate analysis of variance based on the PCA identified MDD-control differences in REM sleep and sleep continuity. In the MDD group, slow wave sleep correlated inversely with age and personality disorder symptoms; sleep continuity correlated with subjective sleep quality and anxiety; and RL/DSR correlated inversely with age. The mean value of the REM factor was higher among treatment non-responders than responders. EEG sleep variables have a similar latent structure in women with MDD and in healthy controls. These sleep factors are supported conceptually and empirically, and correlate with clinical measures in women with MDD. Multivariate statistical techniques decrease the risk of Type I and Type II errors when using a large number of collinear sleep measures, and can clarify conceptual issues related to sleep and depression.

Randomized, controlled trial of amitriptyline versus placebo for adolescents with "treatment-resistant" major depression

OBJECTIVE

To assess the response to a serotonergic/noradrenergic tricyclic antidepressant, amitriptyline (AMI), in a group of adolescents with treatment-resistant major depressive disorder (MDD).

METHOD

Twenty-seven depressed adolescents admitted to a state hospital underwent a 10-week randomized, controlled trial with a flexible dose of AMI or placebo.

RESULTS

There were no differences between patients taking AMI (n = 13) and placebo (n = 14). Both treatment groups showed approximately 70% to 80% improvement on the clinical outcome measurements, and 65% to 70% showed functional improvement. At the end of the protocol, 30% of patients still fulfilled criteria for MDD and had impaired functioning. Patients taking AMI experienced significantly more dry mouth and tachycardia. The final AMI dose was 173.1 mg/day +/- 56.3 mg/day; blood levels were 226.2 ng/mL +/- 80.8 ng/mL.

CONCLUSIONS

No significant differences were found between AMI and placebo, in part because of the high placebo response rate. Although both treatment groups showed substantial response, at the end of treatment a substantial proportion of patients still had MDD of subsyndromal symptoms of depression. This and other studies of tricyclic antidepressants question the use of this medication as first-line treatment for youths with MDD.