Functional Consequences of Insomnia Disorder
Interpersonal, social, and occupational problems may develop as a result of insomnia or excessive concern with sleep, increased daytime irritability, and poor concentration. De- creased attention and concentration are common and may be related to higher rates of ac- cidents observed in insomnia. Persistent insomnia is also associated with long-term consequences, including increased risks of major depressive disorder, hypertension, and quality of life; and increased economic burden.
Normal sleep variations. Normal sleep duration varies considerably across individuals.
sleep duration. Short sleepers differ from individuals with insomnia disorder by the lack of difficulty falling or staying asleep and by the absence of characteristic daytime symptoms (e.g., fatigue, concentration problems, irritability). However, some short sleepers may desire or attempt to sleep for a longer period of time and, by prolonging time in bed, may create an insomnia-like sleep pattern. Clinical insomnia also should be distinguished from normal, age—related sleep changes. Insomnia must also be distinguished from sleep deprivation due to inadequate opportunity or circumstance for sleep resulting, for example, from an emer- gency or from professional or family obligations forcing the individual to stay awake.
Situational/acute insomnia. Situational/acute insomnia is a condition lasting a few days to a few weeks, often associated with life events or with changes in sleep schedules. These fere with social, personal, and occupational functioning. When such symptoms are fre- quent enough and meet all other criteria except for the 3-month duration, a diagnosis of other specified insomnia disorder or unspecified insomnia disorder is made.
Delayed sleep phase and shift work types of circadian rhythm sleep-wake disorder.
Individuals with the delayed sleep phase type of circadian rhythm sleep-wake disorder re- port sleep-onset insomnia only when they try to sleep at socially normal times, but they do delayed and coincide with their endogenous circadian rhythm. Shift work type differs from insomnia disorder by the history of recent shift work.
Restless legs syndrome. Restless legs syndrome often produces difficulties initiating and maintaining sleep. However, an urge to move the legs and any accompanying unpleas- ant leg sensations are features that differentiate this disorder from insomnia disorder.
Breathing-related sleep disorders. Most individuals with a breathing—related sleep dis- order have a history of loud snoring, breathing pauses during sleep, and excessive daytime sleepiness. Nonetheless, as many as 50% of individuals with sleep apnea may also report insomnia symptoms, a feature that is more common among females and older adults.
Narcolepsy. Narcolepsy may cause insomnia complaints but is distinguished from in- somnia disorder by the predominance of symptoms of excessive daytime sleepiness, cat- aplexy, sleep paralysis, and sleep—related hallucinations.
Parasomnias. Parasomnias are characterized by a complaint of unusual behavior or events during sleep that may lead to intermittent awakenings and difficulty resuming sleep.
However, it is these behavioral events, rather than the insomnia per se, that dominate the clinical picture.
Substance/medication-induced sleep disorder, insomnia type. Substance/medication— induced sleep disorder, insomnia type, is distinguished from insomnia disorder by the fact that a substance (i.e., a drug of abuse, a medication, or exposure to a toxin) is judged to be etiologically related to the insomnia (see ”Substance/Medication-Induced Sleep Disor- der” later in this chapter). For example, insomnia occurring only in the context of heavy coffee consumption would be diagnosed as caffeine-induced sleep disorder, insomnia type, with onset during intoxication.