Sleep and circadian rhythms in mood disorders

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65629/1/j.1600-0447.2007.00968.x.pd

Sleep deprivation in Depression:What do we know, where do we go?

Manipulations of the sleep-wake cycle, whether of duration (total or partial sleep deprivation [SD]) or timing (partial SD, phase advance), have profound and rapid effects on depressed mood in 60% of all diagnostic subgroups of affective disorders. Relapse after recovery sleep is less when patients are receiving medication; it may be prevented by co-administration of lithium, pindolol, serotonergic antidepressants, bright light, or a subsequent phase advance procedure. Diurnal and day-to-day mood variability predict both short-term response to SD and long-term response to antidepressant drug treatment. These mood patterns can be understood in terms of a "two-process model of mood regulation" based on the model well established for sleep regulation: the interaction of circadian and homeostatic processes. The therapeutic effect of SD is postulated to be linked to changes in disturbed circadian- and sleep-wake-dependent phase relationships and concomitant increase of slow-wave-sleep pressure; additionally SD-induced sleepiness may counteract the hyperarousal state in depression. This model has the advantage of providing a comprehensive theoretical framework and stringent protocols ("constant routine, " "forced desynchrony") to dissect out specific disturbances. Many aspects tie in with current serotonergic receptor hypotheses of SD action. A treatment inducing euthymia in severely depressed patients within hours is an important therapeutic option that has come of age for clinical use. Biol Psychiatry 1999;46:445-453 (C) 1999 Society of Biological Psychiatry

The significance of sleep physiological disturbances in depression.

Since the discovery of the antidepressant effects of interventions in the sleep-wake cycle, a number of hypotheses have emerged according to which disturbances in sleep physiology are not merely expressions but essential components of the pathophysiology of depression. Three hypotheses are presented, the "Phase-advance", the "S-deficiency" and the "ACh-hypersensitivity" hypotheses. They explain the therapeutic effects of total, partial and selective sleep deprivation as consequences of the normalization of disturbed sleep regulation. The question is dealt with whether there are indications that the hypothesized sleep regulatory disturbances exist and whether there is a relationship between the effects of sleep deprivation on sleep regulation and clinical state. None of the hypotheses is totally supported, none can be fully rejected

The significance of sleep physiological disturbances in depression.

Since the discovery of the antidepressant effects of interventions in the sleep-wake cycle, a number of hypotheses have emerged according to which disturbances in sleep physiology are not merely expressions but essential components of the pathophysiology of depression. Three hypotheses are presented, the "Phase-advance", the "S-deficiency" and the "ACh-hypersensitivity" hypotheses. They explain the therapeutic effects of total, partial and selective sleep deprivation as consequences of the normalization of disturbed sleep regulation. The question is dealt with whether there are indications that the hypothesized sleep regulatory disturbances exist and whether there is a relationship between the effects of sleep deprivation on sleep regulation and clinical state. None of the hypotheses is totally supported, none can be fully rejected

The judgment of facial expressions by depressed patients, their partners and controls

Background: Research has shown that cognitive and interpersonal processes play significant roles in depression development and maintenance. Depressed patients judgments of emotions displayed in facial expressions, as well as those of their partners, allow for better understanding of these processes. Methods: In this study, twenty major depression outpatients, their partners and control persons (matched on the sex and age of the partner) judged facial expressions as to the emotions they felt were portrayed, at the patients outpatient admission. It was expected that the patients would judge the facial expression more negatively and less positively than their partners and that the partners would judge more negatively and less positively than the controls. Results: It was found that while both the patients and partners judged less positive emotions than the controls, the patients and partners did not judge the expressions differently. A trend in the same direction was found between the three groups as to judgment of negative emotions. Conclusion: These findings are related back to interpersonal and cognitive theories of depression. Limitation: A limitation of this study was the somewhat small patient population available for study. Clinical Relevance: This study helps to shed light on the similarity between interpersonal and cognitive processes of depressed patients and their partners. (C) 1998 Elsevier Science B.V

Seasonal affective disorder and latitude: a review of the literature

Background: The aim of the study is to investigate the relationship between the prevalence of SAD and latitude. Methods: An overview of the epidemiological literature on the prevalence of SAD is given and studies relevant for the latitudinal dependency of prevalence will be analyzed and discussed. Results: The mean prevalence of SAD is two times higher in North America compared to Europe. Over all prevalence studies, the correlation between prevalence and latitude was not significant. A significant positive correlation was found between prevalence and latitude in North America. For Europe there was a trend in the same direction. Conclusions: The influence of latitude on prevalence seems to be small and other factors like climate, genetic vulnerability and social–cultural context can be expected to play a more important role. Additional controlled studies taking these factors into account are necessary to identify their influence.