Circadian rhythm sleep disorders

Melatonin secretion is synchronized to the light/dark (LD) cycle, with a nocturnal maximum (in young humans, about 200 pg/ml plasma) and low diurnal baseline levels (about 10 pg/ml plasma). Studies have supported the value of the exogenous administration of melatonin in circadian rhythm sleep disorders, insomnia, cancer, neurodegenerative diseases, disorders of the immune function, and oxidative damage (Karasek et al. 2002 Pandi-Perumal et al. 2005, 2006 Srinivasan et al. 2005a,b, 2006 Hardeland et al. 2006). 

Zisapel, N. (2001). Circadian rhythm sleep disorders pathophysiology and potential approaches to management. CNS Drugs 15, 311-28. 

Breathing-related sleep disorder Circadian rhythm sleep disorder Delayed sleep phase type Jet lag type Shift work type Unspecified type... 

G. S. Richardson and H. V. Malin, Circadian rhythm sleep disorders Pathophysiology and treatment. J. Clin. Neurophysiol. 13, 17-31 (1996). 

C. The sleep disturbance does not occur exclusively during the course of narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia. 

The diagnosis is not made if hypersomnia occurs only during the course of a circadian-rhythm sleep disorder. 

Circadian rhythm sleep disorders jet lag insomnia experienced by shift workers and delayed sleep phase syndrome (sometimes seen in students who are enjoying their first experiences outside the family environment and who go to bed too late). This is something that should be discussed with the present client. 

The sleep-wake cycle is under the circadian control of oscillators and can be disrupted by misalignment between an individual s biological clock and external demands on the sleep cycle. Circadian rhythm sleep disorders usually present with either insomnia or hypersomnia, depending on the individual s performance requirements. Two commonly occurring circadian rhythm sleep disorders are jet lag and shift work sleep problems. 

Causes of excessive daytime sleepiness are numerous and include Intrinsic sleep disorders, such as obstructive sleep apnea/hypopnea syndrome and narcolepsy circadian rhythm sleep disorders, such as jet lag and sleep disorders associated with neuropsychiatric conditions, such as anxiety and depression (42). In many Instances, excessive daytime sleepiness is treated by addressing the underlying cause however, the specific etiology of narcolepsy Is unknown. Narcolepsy also can be characterized by brief periods of muscle paralysis (cataplexy). 

Melatonin [73-31-4] C 2H N202 (31) has marked effects on circadian rhythm (11). Novel ligands for melatonin receptors such as (32) (12), C2yH2gN202, have affinities in the range of 10 Af, and have potential use as therapeutic agents in the treatment of the sleep disorders associated with jet lag. Such agents may also be usehil in the treatment of seasonal affective disorder (SAD), the depression associated with the winter months. Histamine (see Histamine and histamine antagonists), adenosine (see Nucleic acids), and neuropeptides such as corticotropin-like intermediate lobe peptide (CLIP) and vasoactive intestinal polypeptide (VIP) have also been reported to have sedative—hypnotic activities (7). 

The results obtained with the model for the mammalian circadian clock provide cues for circadian-rhythm-related sleep disorders in humans [117]. Thus permanent phase shifts in LD conditions could account for (a) the familial advanced sleep phase syndrome (FASPS) associated with PER hypopho-sphorylation [118, 119] and (b) the delayed sleep phase syndrome, which is also related to PER [120]. People affected by FASPS fall asleep around 7 30 p.m. and awake around 4 30 a.m. The duration of sleep is thus normal, but the phase is advanced by several hours. Moreover, the autonomous period measured for circadian rhythms in constant conditions is shorter [121]. The model shows that a decrease in the activity of the kinase responsible for PER phosphorylation is indeed accompanied by a reduction of the circadian period in continuous darkness and by a phase advance upon entrainment of the rhythm by the LD cycle [114]. 

Poor Timing of Neurotransmission. The activity of some brain circuits, like the secretion of certain hormones, varies at certain times of the day. Called circadian rhythms, the timing of these rhythms may be disrupted in some illnesses. Examples include sleep disorders such as insomnia and narcolepsy, as well as other conditions such as nighttime binge-eating disorder. 

Insomnia is a complaint, not a disease. The causes of insomnia are classified both in the DSM-IV for psychiatrists and in the International Classification of Sleep Disorders for sleep experts (Table 8—3). Insomnia can be a primary problem, or it can be secondary to medical or psychiatric disorders or to medications. Insomnia can also be due psychophysiological factors such as stress or to circadian rhythm distur-... 

Insomnia secondary to a general medical condition, especially with pain- or sleep-disordered breathing Circadian rhythm disturbance Periodic limb movement disorder Restless legs syndrome... 

These factors include sleep, continuous hours of wakefulness, circadian rhythms, and sleep disorders. 

The primary sleep disorders found in elderly that may lead to sleep disturbances are (1) circadian rhythm disturbances (CRD) (2) sleep disordered breathing (SDB) (3) insomnia and (4) restless legs syndrome and periodic limb movement disorder. 

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