Disruption Of Sleep-wake Cycle Research Articles

Lifetime Characteristics of Evening-Preference and Irregular Bed-Rise Time Are Associated With Lifetime Seasonal Variation of Mood and Behavior: Comparison Between Individuals With Bipolar Disorder and Healthy Controls

Sleep–wake cycle disruption and seasonal variation in mood and behavior have been associated with mood disorders. This study aimed to investigate the lifetime characteristics of the sleep–wake cycle and its association with the lifetime characteristics of seasonality in individuals with bipolar disorder. Circadian preference, regularity of bed–rise time, and seasonality were evaluated on a lifetime basis using the Composite Scale of Morningness, the Sleep Timing Questionnaire, and the Seasonal Pattern Assessment Questionnaire in clinically stable individuals with bipolar I/II disorders (n = 103/97) and healthy controls (n = 270). Bipolar groups were more likely to have evening preference and irregular bed–rise time. These characteristics were interrelated and, particularly, more prevalent in bipolar II disorder. Seasonality, which was also more prevalent in the bipolar groups, was associated with evening preference and irregularity of the weekday bed–rise time.

▼Melatonin for primary insomnia?

Melatonin, a hormone produced by the pineal gland, has a key role in regulating circadian rhythms, most importantly, the sleep-wake cycle.1 Melatonin's action has led to its being tried as...

Hypocretin and Human African Trypanosomiasis

To detail clinical and polysomnographic characteristics in patients affected with Trypanosoma brucei gambiense (Tb.g.) human African trypanosomiasis (HAT) at different stages of evolution and to measure and compare cerebrospinal fluid (CSF) levels of hypocretin-1 with narcoleptic patients and neurologic controls. Twenty-five untreated patients affected with T.b.g. HAT were included. The patients were evaluated using a standardized clinical evaluation and a specific interview on sleep complaints. Diagnosis of stages I and II and intermediate stage was performed by CSF cell count and/or presence of trypanosomes: 4 patients were classified as stage II, 13 stage I, and 8 "intermediate" stage. Seventeen untreated patients completed continuous 24-hour polysomnography. We measured CSF levels of hypocretin-1 in all patients at different stages and evolutions, and we compared the results with 26 patients with narcolepsy-cataplexy and 53 neurologic controls. CSF hypocretin-1 levels were significantly higher in T.b.g. HAT (423.2 +/- 119.7 pg/mL) than in narcoleptic patients (40.16 +/- 60.18 pg/ mL) but lower than in neurologic controls (517.32 +/- 194.5 pg/mL). One stage I patient had undetectable hypocretin levels and 1 stage II patient showed intermediate levels, both patients (out of three patients) reporting excessive daytime sleepiness but without evidence for an association with narcolepsy. No differences were found in CSF hypocretin levels between patients with HAT stages; however, the presence of major sleep-wake cycle disruptions was significantly associated with lower CSF hypocretin-1 level with a same tendency for the number of sleep-onset rapid eye movement periods. The present investigation is not in favor of a unique implication of the hypocretin system in T.b.g. HAT. However, we propose that dysfunction of the hypothalamic hypocretin region may participate in sleep disturbances observed in African trypanosomiasis.

Ozone-induced paradoxical sleep decrease is related to diminished acetylcholine levels in the medial preoptic area in rats

Ozone (O 3) produces significant effects on sleep, characterized specially by a decrease in paradoxical sleep (PS) and increase in slow-wave sleep (SWS), which in turn represent a sleep-wake cycle disruption. On the other hand, neuronal activity recorded in the cholinoceptive hypothalamic medial preoptic area (MPO) has been involved in the regulation of sleep. However, there is no direct evidence on the role that acetylcholine (Ach) release in the MPO plays in the sleep-wake cycle. In order to study this relation, we measured the Ach concentration in dialysates collected from MPO in rats exposed to coal-filtered air (clean air) for 48 h and in rats exposed to clean air for 24 h followed by 24-h of O 3 exposure to 0.5 ppm. Polygraphic sleep records were taken simultaneously to neurochemical sampling. O 3 was employed to disrupt the sleep-wake cycle and relate these changes with concomitant disruptions in Ach concentration dialyzed from MPO. A clear circadian pattern of Ach concentration was observed in dialysates from MPO and also in PS, SWS and wakefulness of rats exposed to filtered air. However, O 3 exposure decreased the PS by 65% (Mann–Whitney's U-test, p ≤ 0.0003) and a concomitant decrease of extracellular Ach of 58% ( p ≤ 0.0239) was observed during the light phase. These changes were maintained during the dark phase, although it was also observed that slow-wave sleep increased by 75% ( p ≤ 0.0013) while wakefulness was decreased in 35% ( p ≤ 0.0007). We conclude that Ach release in MPO follows a circadian rhythm that is disrupted by O 3 exposure, and these changes are strongly associated with the O 3-induced PS disruptions.

Melatonin for Treatment and Prevention of Postoperative Delirium

Melatonin for Treatment and Prevention of Postoperative Delirium

Delirium (acute confusional states)

Delirium (acute confusional states), a common and often overlooked psychiatric disorder, can occur at any age, but elderly persons are especially prone to develop it. In later life, it is often a conspicuous feature of systemic or cerebral disease and drug (notably anticholinergic) toxicity, and it may constitute a grave prognostic sign. Its development in a hospitalized patient may interfere with his or her management, disrupt ward routine, and cause medicolegal complications as a result of patient injury. Acute onset of a fluctuating level of awareness, accompanied by sleep-wake cycle disruption, lethargy or agitation, and nocturnal worsening of symptoms, are diagnostic. Early recognition of delirium and treatment of its underlying cause are essential. (<i>JAMA</i>1987;258:1789-1792)