Phase advance of the circadian sleep-wake cycle as an antidepressant

A case of mild school refusal: rest-activity cycle and filial violence

In Japan, adolescent school refusers often commit violence against their parents, particularly against their mothers. The authors investigated the relationship between the test-activity (sleep and wakefulness) cycle and the filial violence of one adolescent school refuser. His mother voluntarily recorded his daily life over a period of about 11 mo. This record included the rest-activity cycle, filial violence, school attendance, and other kinds of behavior. This school refuser was more likely to commit violence during the epoch of disturbed test-activity cycle. We believe that the direct manipulation of the circadian system is worth investigating as a new approach to developing a treatment of school refusal.

Effects of acute and chronic treatment with an atypical antidepressant drug, nomifensine, on the sleep-wake activity in rats

After the chronic administration of saline, rats were treated with nomifensine (0.1 or 1.0 mg/kg, twice a day, at light and dark onset) for 11 days. The sleep-wake activity was recorded for 24 h on the baseline day (saline), on nomifensine days 1, 5 and 11, and also on day 12, when saline was injected again (withdrawal day). Another group of rats was treated with saline throughout the experiment, without significant effect on the sleep-wake activity. The smaller dose of nomifensine increased non-REM sleep (NREMS) at the expense of wakefulness (W) in the light period. The effect persisted throughout the chronic treatment. A late increase in REM sleep (REMS) was noted on nomifensine days 5 and 11. Nomifensine failed to affect the sleep-wake activity in the dark period. On withdrawal, the baseline percentages of the vigilance states were recovered. As evaluated through spectral analysis of the EEG, the increase in NREMS was accompanied by an increase in slow wave activity. The higher dose of nomifensine elicited an increase in W and a reduction in both sleep states, followed by changes in W and NREMS in the opposite directions. These effects were evident in both the light and the dark periods of the day. Chronic treatment resulted in circadian variations in the effects. Withdrawal of the drug abolished the arousal reaction, but the late increase in NREMS persisted. The dose-dependent biphasic effects of nomifensine on sleep-wake activity can be explained by considering the proposed indirect dopamine and possibly noradrenaline agonist activity of the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Antidepressant and circadian phase-shifting effects of light

Bright light can suppress nighttime melatonin production in humans, but ordinary indoor light does not have this effect. This finding suggested that bright light may have other chronobiologic effects in humans as well. Eight patients who regularly became depressed in the winter (as day length shortens) significantly improved after 1 week of exposure to bright light in the morning (but not after 1 week of bright light in the evening). The antidepressant response to morning light was accompanied by an advance (shift to an earlier time) in the onset of nighttime melatonin production. These results suggest that timing may be critical for the antidepressant effects of bright light.

Antidepressant effects of the sleep/wake cycle phase advance. Preliminary report

Five patients with endogenous depression were asked to participate in a phase-advance procedure consisting in advancing by 5 h the time schedule of the major external synchronizers such as light/dark, sleep/wake, meal time and social activity cycles. Clinical and biological parameters were observed throughout this 2-week process which followed one night of partial sleep deprivation. All patients improved with partial sleep deprivation and four of the five showed continuing remission during the phase-advance process. The antidepressant effects of the phase-advance process are discussed in light of different chronobiological models for depression.

Circadian and ultradian rhythms of proliferation in human ovarian cancer

Synchronous waves of proliferation in tumor cells taken from patients with ovarian cancer were observed using flow cytometry to measure the fraction of cells undergoing DNA replication and displaying tumor-cell-specific immunofluorescence. When saline washings of the abdominal cavity were analyzed at 2-4 hr intervals round-the-clock, the percentage of cells in the chromosome replication cycle (S + G2 percentage) showed 12-hr and often higher frequency rhythms in proliferation. These higher frequency rhythms in DNA replication show a relatively constant phase relationship to the patient's circadian clock with peak proliferation occurring most commonly at 10 a.m. to 12 noon and again at 10 p.m. This proliferation rhythm is therefore partially out of phase with the 24-hr rhythms in proliferation seen in normal cells. The findings on human cancer reveal a fundamental difference in the temporal organization of normal and tumor cell growth that should be exploited for therapeutic benefit.

Circadian rhythm of REM sleep of chronic alcoholics during alcohol withdrawal

Sleep structures were polygraphically investigated during the alcohol withdrawal periods of six male alcoholics. Polygraphic recordings were taken 10 days, 1 month and 3 months after hospitalization. Total sleep time was almost equal among the three recording nights for each patient. Stages 3 and 4 sleep were remarkably reduced on all the recording nights. REM sleep time was normal throughout the study. REM latency decreased in many patients on the 10th day, and gradually increased on the following nights. A very important change was observed in the distribution of REM sleep. Maximal duration was noted in the first REM episode on the 10th day in four of the six. On the second recording night the second REM episode was the longest in five of the six subjects. On the last recording night many patients exhibited a normal distribution of REM sleep. These findings which suggest that the acrophase of REM sleep is advanced by several hours for a few months after alcohol withdrawal have also been observed in patients with endogenous depression. Although our patients did not show any depressive symptoms during the study, one of them developed a severely depressive state after he began to drink alcohol thereafter.

REM sleep and depression: further use of computer simulation to test the phase-advance hypothesis

A phase advance of the circadian rhythm of rapid eye movement (REM) sleep propensity relative to the sleep-wake cycle has been proposed to account for the abnormalities of REM sleep commonly found in depressed patients. One implication of this hypothesis is that a phase delay of sleep in normal subjects should produce the same abnormalities of REM sleep. The hypothesis was tested by computer simulation using equations based on data derived from normal subjects who had experienced phase shifts of their bedtime. At phase delays of between 4 and 6 hours (an estimate of the putative phase advance in depressed patients), the mean REM latency and the mean duration of the first REM period predicted by the equations did not differ significantly from those observed in depressed patients. The findings with respect to the distribution of REM latency were more equivocal.

Mood alterations and sleep

We have reviewed literatures about neurobiological aspect of mood disorders in the light of abnormalities of REM sleep. A shortened REM latency is a consistent finding in depressed patients and may be considered a biological marker for depression. Most depressed patients with shortened REM latency also show non-suppression on dexamethasone-suppression test (DST). The commonly used antidepressant drugs cause a significant reduction in REM sleep. Patients with abnormal DST show a better response to sleep deprivation than those with normal DST. Recent studies indicated that borderline patients, primary dysthymic patients and obsessive-compulsive patients (OCD) have shortened REM latency. Farthermore, patients with OCD have a fairly good response to antidepressant clomipramine. Diagnostic and therapeutic strategies can conceivably be related on the examination of sleep patterns of psychiatric patients.

Affective disorders and circadian rhythms

Abnormal circadian rhythms have been associated with affective disorders. A review of this rapidly expanding area of investigation shows that while a clear causal relationship has not yet been proven, a knowledge of the circadian system and its dysfunction can help in understanding unipolar and bipolar depression. Evidence suggests that existing therapies such as lithium and antidepressants act upon the circadian system. Better identification of individuals at risk for affective disorders and the development of new preventive and therapeutic interventions may result from further study of circadian dysfunction.

Comparison of automated REM and slow-wave sleep analysis in young and middle-aged depressed subjects

A comparison of electroencephalographic sleep measures between young and middle-aged groups of depressed inpatients was conducted with specific interest in the application of automated measures of REM and delta wave sleep. Aside from the expected differences in sleep continuity, increased Stage 1 percent, decreased Stage 2 percent, and decreased REM latency in the middle-aged depressives as compared to the younger depressives, distinct findings from automated analyses were noted in the distribution of REM and delta sleep throughout the night. Although the younger depressed patients showed increased numbers of delta waves, the middle-aged depressives showed greater average REM count. Such changes were more pronounced in the first third of the night. Finally, in the middle-aged depressives, little statistical relationship between manual measures of slow-wave sleep and automated measures of delta sleep was found.

Effect of imipramine on the circadian rhythm of plasma melatonin in unipolar depression

The authors took a series of 20 serum samples over a 24-hr period for measurement of melatonin in four men and six women with Major Depressive Disorder (DSM-III), at baseline (depressed) and after 4 weeks on imipramine (150-200 mg/day) after achieving clinical remission. After successful treatment with imipramine, 24-hr secretion and peak levels of melatonin were significantly higher than at baseline, with no difference in time of peak level. Testing after 2 weeks of treatment (four subjects), with only a partial or no clinical response, revealed no differences compared with baseline. The therapeutic efficacy of imipramine may be associated with an enhancement of noradrenergic activity.

The timing of sleep in depression: theoretical considerations

Endogenously depressed subjects frequently show severe sleep problems. In this article sleep time in depression is discussed in relation to a recently developed model for sleep timing in healthy subjects. In terms of the model, two parameter sets survive a qualitative comparison with the empirical data. These are a deficient increase of sleep need (process S) and, alternatively, an increased amplitude of random fluctuations in the wake threshold (process C). Distinct predictions based on these alternatives are discussed.

Sleep and circadian rhythms in affective patients isolated from external time cues

Sleep electroencephalographic activity, circadian rhythms in motor activity and rectal temperature, and clinical state were monitored longitudinally in four affectively ill patients (two depressed, one manic, and one rapidly cycling between depression and mania) who lived in isolation from external time cues (zeitgebers) for 3 to 4 weeks. In these conditions it was possible to observe the intrinsic or free-running behavior of circadian pacemakers and thereby to test several hypotheses about the role of sleep and circadian rhythms in the pathogenesis of depression. No hypothesis was consistently supported by the results. We found that the intrinsic rhythm of a circadian pacemaker appeared to free-run with an abnormally fast frequency in one patient. No patient remained stably depressed during temporal isolation. Our experience suggests that this type of study can be carried out safely with appropriate precautions. Temporal isolation is a means to test decisively predictions of several chronobiological hypotheses about affective illness and should be applied to additional patients.

Antidepressant effects of sleep deprivation in bright and dim light

In order to test whether exposure to bright artificial light at night is a necessary condition for the antidepressant response to sleep deprivation therapy, five patients were totally sleep-deprived on two separate nights, once in very bright light and once in nearly total darkness. During the day after the sleep-deprivation night patients were found to have responded equally well to sleep deprivation in both conditions. During the sleep-deprivation night, however, antidepressant responses may have been greater in the bright light condition. Thus, light at night is not necessary for the antidepressant response to sleep deprivation, but we cannot rule out the possibility that the effects of light exposure and sleep deprivation are additive or that exposure to light at some time after sleep deprivation begins (including during the following day) is necessary for the response.

Auditory laterality in depression: relation to circadian patterns and EEG sleep

Unmedicated endogenous (ED) and nonendogenous depressed (ND) patients were tested in the morning and evening on a dichotic click detection task and a dichotic consonant-vowel (CV) discrimination task. The ED and ND groups showed a morning to evening shift in lateral asymmetry for detecting dichotic clicks, which was opposite in direction to that previously seen for normal subjects. In contrast, there was no morning to evening shift in asymmetry for dichotic CV discrimination. Lateral asymmetry for dichotic click detection was significantly correlated with EEG sleep characteristics (sleep latency, REM period latency, REM time) and ratings of diurnal variation on the Hamilton Depression Scale. A reversal of the normal lateral asymmetry in the morning was associated with lengthened sleep latencies and with clinical ratings of diurnal variation.

Effects of acute and chronic treatment with amitryptyline on the sleep-wake activity of rats

Amitriptyline (1, 5 or 15 mg/kg intraperitoneally, twice a day) was administered to rats and the sleep-wake activity was recorded for either 24 hr (1 mg/kg) or 12 hr (5 or 15 mg/kg) on the day before treatment with amitriptyline, on days 1 and 5 of the treatment and on day 6, when the drug was withdrawn. In the first 3 hr amitriptyline increased non-REM sleep (NREMS), and decreased REM sleep (REMS) and wakefulness; the effects were dose-dependent. The changes in non-REM sleep and wakefulness (W) were followed by a compensatory reaction 6-12 hr after the treatment. The effects of chronic injection of amitriptyline on non-REM sleep revealed a definite decrease only in the case of the 15 mg/kg dose. Rebound of REM sleep appeared after withdrawal of the 5 and 15 mg/kg doses. Amitriptyline at 1 mg/kg had no effect on the sleep-wake activity during the dark period. The results show that the increase in non-REM sleep is as characteristic of amitriptyline as the reduction of REM sleep, and that these effects are resistant to chronic treatment when the dose is small.

Inter-individual differences in the human circadian system: a review

Measurements of physiological, biochemical and psychological variables at two or more different times of day reveal substantial inter-individual differences. This paper reviews studies which have dealt with these differences in terms of the morningness-eveningness, personality (introversion-extraversion), age or sex of their subjects. Studies of individual differences in the response of the circadian system to disturbance (e.g. shift work) are also discussed. The most reliable differences were observed in association with the morningness-eveningness factor. From the studies reviewed here it appeared that several rhythm parameters covaried consistently as a function of morningness-eveningness, suggesting underlying differences in the intrinsic period of the circadian system. It is argued that the differences in rhythm parameters associated with the personality dimension of introversion-extraversion are the result of exogenous influences. The results with regard to age-related and sex-related differences were not sufficient to allow conclusions to be made.

Self-reported diurnal mood changes, early morning awakening and the dexamethasone suppression test in endogenous depression

Several authors have suggested that Dexamethasone Suppression Test (DST) non-suppression is related to circadian alternations of hypothalamic-pituitary-adrenal function. Two clinical manifestations of altered circadian rhythms in depressed patients are early morning awakening and diurnal variation in mood. To observe whether these clinical symptom patterns were associated with an increased frequency of abnormal DSTs, we examined post-DST plasma cortisol concentrations and matched clinical ratings of early morning awakening and diurnal variation in mood in 49 patients with major depressive disorder, endogenous subtype. We found no significant association between these clinical and laboratory variables.

Approaches to the evaluation and treatment of rapid-cycling affective illness

The definition and clinical aspects of rapid cycling affective illness are reviewed and various factors associated with the onset and maintenance of rapid cycling enumerated. On the basis of this information and of reports of the response of rapid cycling patients to various treatment interventions, an approach is suggested to the evaluation and treatment of rapid cycling affective illness.