Are there predictors for sleep deprivation response in depressed patients?

Antidepressant effects of acute sleep deprivation are reduced in highly controlled environments

BACKGROUND

Numerous studies summarized in a recent meta-analysis have shown sleep deprivation rapidly improves depressive symptoms in approximately 50 % of individuals with major depressive disorder (MDD), however those studies were typically conducted in clinical settings. Here we investigated the effects of sleep deprivation utilizing a highly controlled experimental approach.

METHODS

36 antidepressant-free individuals with MDD and 10 healthy controls (HC) completed a 5 day/4-night protocol consisting of adaptation, baseline, total sleep deprivation (TSD), and recovery phases. Light was kept consistently dim (≤50 lx), meals were regulated, and activity was restricted. In-the-moment mood was assessed using a modified Hamilton Rating Scale for Depression (HRSD) at screening and each morning following the experimental nights.

RESULTS

Day of study had a significant effect on mood in both groups. Post-hoc analyses revealed that significant effects were attributed to mood improvement in the MDD group following study initiation prior to beginning TSD, and in the HC group following recovery sleep, but were not due to mood improvement in the MDD group during TSD. No further improvement in mood occurred during 36 h of TSD.

LIMITATIONS

Strict eligibility requirements may limit generalizability. The requirement to be medication free may have biased toward a less severely depressed sample.

CONCLUSIONS

Results revealed that individuals with moderate MDD can experience a significant reduction in depressive symptoms upon entering a highly controlled laboratory environment. Environmental effects on mood can be substantial and need to be considered.

Self-perceived rhythmicity in affective and cognitive functions is related to psychiatric symptoms in adolescents

The objective of this study was to evaluate the relationship between self-perceived rhythms measured using the Mood Rhythm Instrument for adolescents (MRhI-Y) and depressive and psychiatric symptoms measured with the Children's Depressive Instrument (CDI) and the Strengths and Difficulties Questionnaire (SDQ). In this study, 186 adolescents were recruited in Rio Grande do Sul, Brazil. We performed a Spearman correlation analysis to evaluate the relationships between quantitative variables. All variables that had a statistically significant correlation were included in ANOVA multiple regression models. The dependent variables in the multiple regression analyses were CDI score and total and emotional scores on the SDQ. We found that only Cognitive self-perceived rhythmicity contributed significantly to the first multiple regression with CDI as the outcome variable. The second regression with SDQ Emotional score as the outcome variable showed that female sex, age, and self-perceived affective rhythmicity contributed significantly to the model. The third regression with SDQ total score as the outcome variable showed that chronotype, self-perceived cognitive symptoms, and affective rhythmicity contributed significantly to the model. In conclusion, we found that lower self-perceived rhythmicity in cognitive factors and higher self-perceived rhythmicity in affective factors were related to presence and intensity of psychiatric and depressive symptoms.

Sleep, insomnia, and depression

Since ancient times it is known that melancholia and sleep disturbances co-occur. The introduction of polysomnography into psychiatric research confirmed a disturbance of sleep continuity in patients with depression, revealing not only a decrease in Slow Wave Sleep, but also a disinhibition of REM (rapid eye movement) sleep, demonstrated as a shortening of REM latency, an increase of REM density, as well as total REM sleep time. Initial hopes that these abnormalities of REM sleep may serve as differential-diagnostic markers for subtypes of depression were not fulfilled. Almost all antidepressant agents suppress REM sleep and a time-and-dose-response relationship between total REM sleep suppression and therapeutic response to treatment seemed apparent. The so-called Cholinergic REM Induction Test revealed that REM sleep abnormalities can be mimicked by administration of cholinomimetic agents. Another important research avenue is the study of chrono-medical timing of sleep deprivation and light exposure for their positive effects on mood in depression. Present day research takes the view on insomnia, i.e., prolonged sleep latency, problems to maintain sleep, and early morning awakening, as a transdiagnostic symptom for many mental disorders, being most closely related to depression. Studying insomnia from different angles as a transdiagnostic phenotype has opened many new perspectives for research into mechanisms but also for clinical practice. Thus, the question is: can the early and adequate treatment of insomnia prevent depression? This article will link current understanding about sleep regulatory mechanisms with knowledge about changes in physiology due to depression. The review aims to draw the attention to current and future strategies in research and clinical practice to the benefits of sleep and depression therapeutics.

Genetic Advance in Depressive Disorder

Major depressive disorder (MDD) and bipolar disorder (BPD) are both chronic, severe mood disorder with high misdiagnosis rate, leading to substantial health and economic burdens to patients around the world. There is a high misdiagnosis rate of bipolar depression (BD) just based on symptomology in depressed patients whose previous manic or mixed episodes have not been well recognized. Therefore, it is important for psychiatrists to identify these two major psychiatric disorders. Recently, with the accumulation of clinical sample sizes and the advances of methodology and technology, certain progress in the genetics of major depression and bipolar disorder has been made. This article reviews the candidate genes for MDD and BD, genetic variation loci, chromosome structural variation, new technologies, and new methods.

Mechanisms of rapid antidepressant effects of sleep deprivation therapy: clock genes and circadian rhythms

A significant subset of both major depressive disorder and bipolar disorder patients rapidly (within 24 hours) and robustly improves with the chronotherapeutic intervention of sleep deprivation therapy (SDT). Major mood disorder patients are reported to have abnormal circadian rhythms including temperature, hormonal secretion, mood, and particularly sleep. These rhythms are modulated by the clock gene machinery and its products. It is hypothesized that SDT resets abnormal clock gene machinery, that relapse of depressive symptoms during recovery night sleep reactivates abnormal clock gene machinery, and that supplemental chronotherapies and medications can block relapse and help stabilize circadian-related improvement. The central circadian clock genes, BMAL1/CLOCK (NPAS2), bind to Enhancer Boxes to initiate the transcription of circadian genes, including the period genes (per1, per2, per3). It is suggested that a defect in BMAL1/CLOCK (NPAS2) or in the Enhancer Box binding contributes to altered circadian function associated, in part, with the period genes. The fact that chronotherapies, including SDT and sleep phase advance, are dramatically effective suggests that altered clock gene machinery may represent a core pathophysiological defect in a subset of mood disorder patients.

Polysomnography and criteria for the antidepressant response to sleep deprivation

BACKGROUND

One night of total or partial sleep deprivation (SD) produces a temporary remission in 40-60% of patients with major depression. Yet no attempts to determine the optimum response criterion(a) for the antidepressant response to SD have been published.

METHODS

Twenty-three unmedicated major depression patients received polysomnography (PSG) on an adaptation night; a baseline night; a partial SD (PSD) night (awake after 3 a.m.); and a "recovery" night. Subjects received the Hamilton Depression Rating Scale (HDRS17) at standard times during baseline and PSD days and at 8 a.m. after the "recovery" night. Response was defined as percent decrease in the modified HDRS17 (HDRS17Mod) (omitting sleep and weight loss items) from baseline to the minimum following PSD. Using cutoffs of 30%, 35%, 40%, and 50% to dichotomize responders and nonresponders, PSG variables were analyzed for between-group differences.

RESULTS

All cutoffs differentiated responders' and nonresponders' mood response to PSD despite similar baseline values. Sleep continuity measures most consistently differed between responders and nonresponders on baseline and recovery nights. None of the response cutoffs tested were clearly "best" in terms of detecting the most PSG differences between groups.

LIMITATIONS

More subjects may be needed.

CONCLUSIONS

Given the increasing interest in SD for clinical and research applications, as well as its proposed use for subtyping depression, further study to determine the optimal response criterion(a) for the antidepressant response to SD is warranted. Planned pooling of multisite data on standardized SD protocols could help determine the optimal cutpoint for response.

Etiology, pathogenesis, and treatment of seasonal and non-seasonal mood disorders: possible role of circadian rhythm abnormalities related to developmental alcohol exposure

Developmental alcohol exposure adversely influences the developing brain. Alcohol exposure during rapid brain growth causes cell loss, alters connections between brain regions, and lowers the production of biological substances responsible for the communication among neurons. It is reasonable to suggest that alcohol may adversely affect the development of suprachiasmatic nuclei (SCN), the master circadian pacemaker. Multiple research reports suggest that abnormalities in circadian rhythms are involved in the etiopathogenesis of seasonal affective disorder (SAD), a syndrome in which depression develops during autumn or winter and remits the following spring or summer. Several lines of evidence suggest that changes in the circadian system are also involved in the development of nonseasonal mood disorders, such as major depression and bipolar disorder. Thus, developmental alcohol exposure produces subtle abnormalities in circadian rhythms that may contribute to the development of seasonal and nonseasonal mood disorders. Pharmacological, psychological, and light treatments of mood disorders have multiple effects on circadian function. The state of the circadian system may affect a response to treatment. Circadian rhythms have been reported for neurotransmitters, receptors, enzymes, and the second messenger system in the brain that are involved in the effects of treatments. Some of these rhythms have amplitudes as large as several 100%. Effects of many psychotropic medications depend on the time of administration in relation to body rhythmicity. Therefore, subtle circadian rhythm abnormalities related to developmental alcohol exposure may affect treatment response in patients with mood disorders.

Sleep and manipulations of the sleep-wake rhythm in depression

OBJECTIVE

Disturbed sleep is typical for most depressed patients and complaints about disordered sleep are the hallmarks of the disorder. Polysomnographic sleep research has demonstrated that besides impaired sleep continuity, sleep in depression is characterized by a reduction of slow wave sleep and a disinhibition of random eye movement (REM) sleep, with a shortening of REM latency, a prolongation of the first REM period and increased REM density.

METHOD

Our own experimental work has focused on the reciprocal interaction hypothesis of non-REM and REM sleep regulation as a model to explain the characteristic features of depressed sleep.

RESULTS

In agreement with the major tenet of this model, administration of cholinomimetics provoked shortened REM latency in healthy subjects and led to an even stronger REM sleep disinhibition in depressed patients. Manipulations of the sleep-wake cycle, such as sleep deprivation or a phase advance of the sleep period, alleviate depressive symptoms.

CONCLUSION

These data indicate a strong bidirectional relationship between sleep, sleep alterations and depression.

Sleep and sleep-wake manipulations in bipolar depression

In the last 30 years, it has been convincingly demonstrated that sleep in major depression is characterized by disturbances of sleep continuity, a reduction of slow wave sleep, a disinhibition of REM sleep including a shortening of REM latency (i.e. the time between sleep onset and the occurrence of the first REM period) and an increase in REM density. Furthermore, manipulations of the sleep-wake cycle like total or partial sleep deprivation or phase advance of the sleep period have been proven to be effective therapeutic strategies for patients with unipolar depression. The database concerning sleep and sleep-wake manipulations in bipolar disorder in comparison is not yet as extensive. Studies investigating sleep in bipolar depression suggest that during the depressed phase sleep shows the same stigmata as in unipolar depression. During the hypomanic or manic phase, sleep is even more curtailed, though subjectively not experienced as disturbing by the patients. REM sleep disinhibition is present as well. An important issue is the question, whether sleep-wake manipulations can also be applied in patients with bipolar depression. Work by others and our own studies indicate that sleep deprivation and a phase advance of the sleep period can be used to treat bipolar patients during the depressed phase. The risk of a switch into hypomania or mania does not seem to be more pronounced than the risk with typical pharmacological antidepressant treatment. For patients with mania, sleep deprivation is not an adequate treatment--in contrast, treatment strategies aiming at stabilizing a regular sleep-wake schedule are indicated.

Potential mechanisms of the sleep therapies for depression

Sleep deprivation for one night has been investigated as a treatment for depression since the first publications describing its antidepressant properties almost 30 years ago [Pflug and Tolle, 1971: Int Pharmacopsychiatry 6:187-196]. It remains a field of active research. It is the only intervention consistently demonstrated to produce next-day antidepressant results. This makes sleep deprivation an exciting and unique tool to study the pathophysiology of depressive disorders and to formulate targets for novel antidepressant agents. Importantly, it is also an effective, but underused, clinical treatment for unipolar and bipolar depression.

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.

Delta sleep ratio as a predictor of sleep deprivation response in major depression

The fast but short-lasting improvement of depressive symptoms by sleep deprivation (SD) in about 60% of patients with a major depressive disorder is well established, but the mechanisms of action are still not clear. Recent studies suggest that changes in non rapid eye movement (NREM) sleep, especially in slow wave activity (SWA), could be associated with the therapeutic outcome of SD. In the current study, spectral analysis of NREM sleep EEG directly prior to SD was performed to determine if automatically derived sleep parameters predict SD response. Sixteen pair matched and drug free patients with a major depressive disorder, 8 SD responders and 8 non-responders (response criterion: 50% reduction on the 6-item HAMD score), were included. Average EEG spectral power was calculated for the whole night before SD and for single NREM episodes. While whole-night averages of spectral power did not differ significantly between subgroups, SD responders showed a steady decrease of SWA across successive NREM episodes, whereas in non-responders an increase from the first to the second episode was observed. The different distribution of SWA was significantly expressed in the delta sleep ratio (quotient of SWA in the first to the second NREM episode). In conclusion, a high delta sleep ratio is a positive predictor for SD response. Referred to psycho- and pharmacotherapeutic results it is hypothesized that low and high values of the delta sleep ratio characterize subgroups of depressed patients with different neurobiological alterations, which could be relevant for further scientific and therapeutic approaches.

Preliminary evidence of an association between increased REM density and poor antidepressant response to partial sleep deprivation

BACKGROUND

One night of total sleep deprivation or of late-night partial sleep deprivation (PSD) produces a temporary remission in approximately 40-60% of patients with major depressive disorder; however, little is known about polysomnography (PSG) characteristics of responders to these types of sleep deprivation (SD).

METHODS

Twenty-three unmedicated unipolar patients (17-item Hamilton Depression Rating Scale (HDRS17) >16) and 14 normal controls underwent 1 night of late-night PSD (awake after 3 a.m.) Subjects underwent baseline PSG and received the HDRS17 at standard times before and after PSD. Clinical response was defined as a reduction of >30% in the modified HDRS17 (omitting sleep and weight loss items) following PSD.

RESULTS

The 12 responders and 11 nonresponders did not differ from each other significantly on baseline HDRS17 or PSG variables. The only PSG variable correlating with percent decrease in modified HDRS17 was baseline REM density (Pearson's r=-0.52, n=23, P=0.01.) In other words, the lower the baseline REM density, the more robust the antidepressant response was.

LIMITATIONS

Subject numbers are relatively small.

CONCLUSIONS

Increased REM density, which reflects the number of rapid eye movements per epoch of REM sleep, may be a physiological marker for severity or poor prognosis in a variety of psychiatric disorders, including relapse in recovering alcoholics, suicidality in schizophrenia, and poor response to PSD or interpersonal psychotherapy in depression.

Sleep deprivation therapy in depressive illness and Parkinson's disease

1. Sleep deprivation is commonly associated with feelings of fatigue and cognitive impairment. 2. Patients with depressive illness, however, often experience mood improvements under these same conditions. 3. Other studies now show that tremor and rigidity, in patients with Parkinson's disease, are also improved by sleep depression therapy. 4. The neural substrates which underlie these effects are unclear. Some recent evidence, however, suggests that sleep deprivation may activate mechanisms which are otherwise typical of conditions of metabolic stress. 5. A common feature of these mechanisms is the suppression of cholinergic activity which is thought to be excessive, in relation to monoamine transmission, in both depression and Parkinson's disease.

Critical analysis of the theories advanced to explain short REM sleep latencies and other sleep anomalies in several psychiatric conditions

One of the most consistent and most studied sleep modifications in several psychiatric conditions is the shortening of the rapid eye movement (REM) sleep latency. While its clinical usefulness is still to be proven and its meaning relatively obscure, the appearance of a short REM latency continues to be a daily fact in sleep laboratories. Many theories compete to explain what is observed, the most important being the circadian rhythm hypotheses, the homeostatic model and the reciprocal interaction model. These three are summarised and their pros and cons are exposed in a systematic manner. Points of conflict, possible convergences and limitations are discussed in the light of recent developments on the general theories of sleep regulation.

Sleep in psychiatric disorders

Psychiatric disorders are some of the most common causes of sleep-related complaints, particularly insomnia. Sleep abnormalities may be caused by CNS abnormalities associated with psychiatric illnesses as well as by accompanying behavioral disturbances. Although sleep patterns are not necessarily diagnostic of particular psychiatric disorders, there are relationships between certain sleep abnormalities and categories of psychiatric disorders. Sleep disturbances associated with psychiatric disorders and general approaches to treatment are reviewed.

Advanced vs. normal sleep timing: effects on depressed mood after response to sleep deprivation in patients with a major depressive disorder

Total sleep deprivation (TSD) exerts beneficial but only transient effects on mood in patients with a major depressive disorder (MDD). Though approximately 50 to 70% of depressed patients improve after sleep deprivation, the majority relapse after recovery sleep, some even after a short nap. One theoretical model postulates a critical period in the early morning hours where sleep is likely to induce a relapse, and nap studies indicate that sleep may be particularly 'depressogenic' at this time of day. A second model attributes the relapse to the release of non-REM sleep. We therefore compared the impact of an advanced sleep period (17:00-24:00 h) to a normal sleep period (23:00-06:00 h) on mood in patients who had responded to sleep deprivation. Less relapses into depression occurred after advanced sleep. Polysomnographic data showed that, as expected, normal sleep was characterized by a more pronounced improvement of sleep continuity and increased slow-wave sleep. The normal sleep group showed a stronger decrease in REM sleep density than the advanced sleep group compared with baseline. These data add to a growing body of evidence that the timing of sleep following successful sleep deprivation may be crucial for a stabilization of its antidepressant effect. Thus, avoidance of sleep during a "critical period' for more than a single night is necessary to provide a longer-lasting treatment modality.

A longitudinal study of diurnal mood variation in depression; characteristics and significance

The course of 39 depressed in-patients' daily mood was recorded by means of frequent self-ratings during their entire stay (in total 3718 days). The frequency of diurnal variations largely varies between subjects without clear dichotomy in 'diurnal' and 'non-diurnal' subjects and the occurrence of diurnal variations is rather irregular. Mood variability measures rather than average daily mood improvement correlate with the response to sleep deprivation. These observations do not support theories of chronobiological rhythm disturbances in depression. It is argued that depressed subjects largely vary in susceptibility to stimuli. Signals generated by the biological clock or by processes related to the sleep-wake cycle are considered examples of such stimuli.

Symposium: Normal and abnormal REM sleep regulation: REM sleep in depression-an overview

Abnormalities of REM sleep, i.e. shortening of REM latency, lengthening of the duration of the first REM period and heightening of REM density, which are frequently observed in patients with a major depressive disorder (MDD), have attracted considerable interest. Initial hopes that these aberrant patterns of sleep constitute specific markers for the primary/endogenous sub-type of depression have not been fulfilled. The specificity of REM sleep disinhibition for depression in comparison with other psychopathological groups is challenged as well. Demographic variables like age and sex exert strong influences on sleep physiology and must be controlled when searching for specific markers of depressed sleep. It is still an open question whether abnormalities of sleep are state- or trait-markers of depression. Beyond baseline studies, the cholinergic REM induction test (CRIT) indicated a heightened responsitivity of the REM sleep system to cholinergic challenge in depression compared with healthy controls and other psychopathological groups, with the exception of schizophrenia. A special role for REM sleep in depression is supported by the well-known REM sleep suppressing effect of most antidepressants. The antidepressant effect of selective REM deprivation by awakenings stresses the importance of mechanisms involved in REM sleep regulation for the understanding of the pathophysiology of depressive disorders. The positive effect of total sleep deprivation on depressive mood which can be reversed by daytime naps, furthermore emphasizes relationships between sleep and depression. Experimental evidence as described above instigated several theories like the REM deprivation hypothesis, the 2-process model and the reciprocal interaction model of nonREM-REM sleep regulation to explain the deviant sleep pattern of depression. The different models will be discussed with reference to empirical data gathered in the field.

Naps after total sleep deprivation in depressed patients: are they depressiogenic?

Total sleep deprivation (TSD) exerts beneficial but transient effects on mood in approximately 60% of patients with a major depressive disorder. The positive effects of a night of total sleep deprivation are generally reversed after the next night of sleep. Several anecdotal reports and a pilot study by our group indicated that even short naps during the period of sleep deprivation are capable of re-inducing depressive mood in responders to TSD. The present study explored whether the structure of naps at 9 a.m. was crucial for the "depressiogenic" impact of naps on mood. A negative effect on mood was replicated, but this effect was not related to any of the nap sleep variables. The effect of naps on mood was attenuated in the early afternoon. The results support the assumption of a "depressiogenic" effect of naps in patients with major depression after successful TSD.

Effect of morning and afternoon naps on mood after total sleep deprivation in patients with major depression

In 30 depressed patients who had responded to total sleep deprivation therapy, morning naps led more frequently to relapses into depression than did afternoon naps. Longer naps were less detrimental than shorter ones, and there was no significant relationship between the effect of a nap on mood and its content of slow-wave-sleep. The amount of the rapid eye-movement sleep, too, was unrelated to clinical nap effects. Thus, some of the current theories on the relationship between sleep and depressive symptomatology are not supported by the data. Our results demonstrate the importance of nap timing, suggesting a circadian variation of propensity to relapse into depression.