Primary sleep disorder

Although we are focusing on the primary sleep disorders, sleep disturbance quite often occurs as a symptom of another illness. Depression, anxiety, and substance abuse can impair the quality of sleep, though in the setting of chronic insomnia, other psychiatric disorders account for less than 50% of cases. Nightmares are a frequent complication of post-traumatic stress disorder (PTSD), and pain, endocrine conditions, and a host of medical illnesses can produce sleep problems. Thus, when discussing insomnia or hypersomnia, we are well advised to remember that these can be either a symptom of a psychiatric syndrome, a medical illness, or a sleep disorder. 

Le Bon O, Hoffmann G, Murphy J, De Meirleir K, Cluydts R, Pelc I. How significant are primary sleep disorders and sleepiness in the chronic fatigue syndrome Sleep Res Online 2000 3 43-48. 

Moreover, there is evidence for increased rates of ADHD symptoms in clinical populations of children with sleep disorders, including children with the obstructive sleep apnea syndrome (OSAS), periodic limb movements of sleep (PLMS), narcolepsy, and sleep-wake schedule disorders. Studies indicate that treating the primary sleep disorder can produce significant improvement in ADHD symptoms (103). 

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. 

To ensure proper diagnosis and treatment of insomnia, and to rule out other primary sleep disorders, a physician should obtain a thorough sleep, medical and psychiatric... 

In addition to the sleep disturbances that result from normal aging or brain disease, sleep quality may be impaired by primary sleep disorders, some of which occur with increasing prevalence with age. Sleep disordered breathing (sleep apnea), restless legs syndrome (RLS) and REM sleep behavior disorder (RBD) are three such primary sleep disorders that are more prevalent in older adults. 

Although it might be expected that the incidence of the primary sleep disorders would increase in demented patients relative to age-matched controls because of the CNS dysfunction underlying these disorders, studies comparing the rates of sleep apnea in dementia patients and aged controls have not found consistent differences. Nevertheless, these conditions may interact with the dementia syndrome to further worsen sleep quality as well as cognitive and functional abilities. For example, some studies have shown that sleep apnea is associated with increased morning confusion in AD patients. 

Song C, Lin A, Bonaccorso S, Heide C, VerkerkR, Bienis G, Bosmans E, Scharpe S, Whelan A, Cosyns P, De Jongh R, Maes M (1998) The inflammatory response system and the availability of plasma tiyptophan in patients with primary sleep disorders and major depression. J Affect Disord 49 211—219. 

Sleep disorders may be divided into two main groups primary and secondary sleep disorders. Primary sleep disorders refer to those disorders of sleep not due to another medical or psychiatric condition. Secondary sleep disorders are those resulting from other conditions. Examples include the early morning awakening of depression and the insomnia of thyrotoxicosis. Our discussion here is limited to the primary sleep disorders, although secondary sleep disorders are referred to throughout the book. 

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