Sleep Wake Disorders

 To understand sleep and its disorders, it helps to begin with sleep’s three essential characteristics: (1) Sleep is a process required for proper brain function. Failure to sleep impairs thought processes, mood regulation, and a host of normal physiologic functions. (2) Sleep is not a single process; there are several distinct types of sleep. These different types of sleep differ both qualitatively and quantitatively. Each type of sleep has unique characteristics, functional importance, and regulatory mechanisms. Selectively depriving one particular type of sleep produces compensatory rebound when an individual is allowed to sleep ad lib. (3) Sleep is not a passive process; during sleep, there is a high degree of brain activation and metabolism.

The science of sleep is a fascinating ever-growing topic, that is, perhaps unfortunately, beyond the repertoire of the average psychiatrist, and we refer the interested reader to the Comprehensive Textbook’s discussion of the basic science of sleep, discussed about the neural sciences.

Several basic mechanisms regulate sleep, and when these systems go awry, sleep disorders occur. Sleep disorders are both dangerous and expensive. Hypersomnolence is a serious, potentially life-threatening condition affecting not only the sleepy individual but also their family, coworkers, and society in general. Sleep-related motor vehicle accidents represent a significant public safety concern, with some states enacting criminal statutes to deter sleepy driving. Investigations link many major industrial catastrophes to sleepiness. Research shows that sleep-disordered breathing contributes to hypertension, heart failure, and stroke. Sleep disorders’ direct cost per annum in the United States is about $16 billion, with indirect costs ranging upward to more than$100 billion.


This chapter’s disorders all describe disturbances in healthy sleep. Among them, however, there is considerable variation.

It is helpful to understand the stages of sleep and electrophysiologic criteria. Table 15-1 and Figure 15-1 illustrate some of the features of normal sleep.

Insomnia Disorder

Persons with insomnia primarily have difficulty falling asleep, difficulty staying asleep, or trouble waking early with an inability to fall back to sleep, sufficient to impair their functioning. In children, this may manifest as resistance to caregiver designation of bedtime or difficulty sleeping without some sort of intervention from the caregiver.

Hypersomnolence Disorder

Hypersomnolence broadly refers to excessive sleepiness and time sleeping. During the day, people are drowsy and have reduced attention. Excessive sleepiness can be a serious, debilitating, potentially life-threatening condition. It affects not only the patient but their family, colleagues, and the public. Not due to disrupted sleep or circadian problems, hypersomnolence disorder likely results from some fundamental neurologic sleep regulation dysfunction.


People with narcolepsy have an overwhelming desire to sleep and may suddenly fall asleep, even if it is not appropriate to do so. Also, they may experience cataplexy, or the sudden loss of muscle tone, usually with continuing full or partial consciousness. Laughter, or other strong emotions, commonly precipitate the cataplexy. Cataplexy can range from transient weakness in the knees to total paralysis while the patient is fully conscious. Episodes may last from several seconds to minutes. Usually, the patient is unable to speak and may fall to the floor. Sleep paralysis and hypnagogic (or hypnopompic) hallucinations may occur. 

Sleep-Related Breathing Disorders

People who present with sleep-related breathing disorders experience an interruption of normal respiration that impacts their sleep, often resulting in CNS arousal and, consequently, daytime sleepiness. Sleep-related breathing disorders include conditions involving large airway obstruction during sleep, breathing cessation resulting from central respiratory mechanisms, and hypoventilation without breathing cessation. Those affected may experience sleep-related breathing cessation (sleep apnea), in which the patient stops breathing for 10 seconds or more during sleep. They may instead have reduced breathing or hypopnea. Airway obstruction is the usual case of these impairments, however central (brainstem) pathology can also be the cause. When asleep, breathing cessations or reductions typically provoke CNS arousal, significant oxyhemoglobin desaturation, or both. Sleep apnea can obstructive, central, or mixed, depending on the cause.

The clinical presentation of the sleep-related breathing disorders varies depending on the mechanism of the disorder. Table 15-2 lists some of these symptoms.

Circadian Rhythm Sleep–Wake Disorders

Circadian rhythm sleep disorders include a wide range of conditions involving a misalignment between desired and actual sleep periods. This collection of sleep disorders shares the same primary underlying etiology—a desynchrony between an individual’s internal circadian biologic clock and the desired or conventional sleep–wake cycle. The circadian pacemaker is in the suprachiasmatic nucleus (SCN). SCN firing oscillates with an almost sinusoidal pattern, the period of which is 24 hours, and the output correlates with the daily fluctuations in core body temperature. Mismatched circadian clock and desired schedules can arise from improper phase relationships between the two, travel across time zones, or dysfunctions in the basic biologic rhythm. Under normal circumstances, the internal circadian pacemaker is reset each day by bright light, social cues, stimulants, and activity. In cases in which these factors fail to reentrain the circadian rhythm, the circadian sleep disorders occur.

Parasomnias and Sleep-Related Movement Disorders

Parasomnias are disorders of partial arousal. In general, the parasomnias are a diverse collection of sleep disorders characterized by physiologic or behavioral phenomena that occur during or are potentiated by sleep. One conceptual framework views many parasomnias as overlaps or intrusions of one sleep–wake state into another. Usually, we divide sleep into three basic states: wakefulness, non–rapid eye movement (NREM) sleep, and REM. Each has a unique neurologic organization. During wakefulness, both the body and brain are active. In NREM sleep, both the body and brain are much less active. REM sleep, however, pairs an atonic body with an active brain (capable of creating elaborate dream fantasies). Regional cerebral blood flow, magnetic resonance imaging (MRI), and other imaging studies confirm increased brain activation during REM sleep. It certainly appears that in some parasomnias, there are state boundary violations. For example, arousal disorders (sleepwalking and sleep terrors) involve momentary or partial wakeful behaviors suddenly occurring in NREM sleep. Similarly, isolated sleep paralysis is the persistence of REM sleep atonia into the wakefulness.

transition, whereas REM sleep behavior disorder (RBD) is the failure of the mechanism creating paralytic atonia such that individuals act out their dreams.

There are many sleep-related movement disorders. These disorders typically involve relatively simple bodily movements that impact sleep. Table 15-3 lists examples of these disorders.


Three different nosologies provide classification systems for sleep disorders:(1) the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5), (2) the International Classification of Sleep Disorders, third edition (ICSD-3), and (3) the International Classification of Diseases, 10th edition (ICD-10). Most general psychiatrists use the DSM-5 approach. However, Sleep Medicine specialists often prefer the ICSD-3. We have included a listing of ICSD sleep–wake disorders for reference (Table 15-4).

asleep, staying asleep, or waking early with difficulty getting back to sleep. While there are no formal criteria for diagnostic subtypes of insomnia, the ICSD-3 does describe each subtype briefly. We describe the insomnia subtypes here to highlight possible insomnia nuances and complications. We present a comparison of the different approaches to diagnosing insomnia in Table 15-5.

Psychophysiologic Insomnia. Psychophysiologic insomnia (PPI) involves conditioned arousal with the thought of sleeping. Objects related to sleep (e.g., the bed, the bedroom) likewise have become conditioned stimuli that evoke insomnia. Daytime adaptation is usually good; however, there can be extreme tiredness, and the affected person can become desperate. PPI often occurs in combination with stress and anxiety disorders, delayed sleep phase syndrome, and hypnotic use and withdrawal. Table 15-6 lists some typical characteristics of PPI.


Ms. W is a 41-year-old, divorced white female presenting with a two- and one-half year complaint of sleeplessness. She has some difficulty falling asleep (30- to 45-minute sleep-onset latency) and awakens every hour or two after sleep onset. These awakenings may last 15 minutes to several hours, and she estimates approximately 4.5 hours of sleep on an average night. She rarely takes daytime naps notwithstanding feeling tired and edgy. The patient describes her sleep problem with the following words, “It seems like I never get into a deep sleep. I have never been a heavy sleeper, but now the slightest noise wakes me up. Sometimes I have a hard time getting my mind to shut down.” She views the bedroom as an unpleasant place of sleeplessness and states, “I tried staying at a friend’s house where it is quiet, but then I couldn’t sleep because of the silence.”

At times, Ms. W is unsure whether she is asleep or awake. She has a history of clock watching (to time her wakefulness) but stopped doing this when she realized it was contributing to the problem. Reportedly the insomnia is unrelated to seasonal changes, menstrual cycle, or time-zone translocation. Her basic sleep hygiene is good. Appetite and libido are unchanged. She denies mood disturbance, except that she is quite.

frustrated and concerned about sleeplessness and its effect on her work. Her work involves sitting at a microscope for 6 hours out of a 9-hour working day and meticulously documenting her findings. Her final output has not suffered, but she must now “double check” for accuracy.

She describes herself as a worrier and a Type-A personality. The patient does not know how to relax. For example, on vacation she continually worries about things that can go wrong. She will not even begin to unwind until she has arrived at the destination, checked in, and unpacked. Even then, she is unable to relax.

Medical history is unremarkable except for tonsillectomy (age 16 years), migraine headaches (current), and diet-controlled hypercholesterolemia. She takes naproxen as needed for headache. She does not currently drink caffeinated beverages, smoke tobacco, or drink alcoholic beverages. She does not use recreational drugs.

The problem with insomnia began after relocation to a new city and place of employment. She attributes her insomnia to the noisy neighborhood in which she now lives. She first sought treatment 18 months ago. Her family practice physician diagnosed depression, and she was started on fluoxetine that made her “climb the walls.” Antihistamines were tried next with similar results. She was then switched to low-dose trazodone (for sleep) and developed nausea. After these medical interventions, she sought medical care elsewhere. Zolpidem 5 mg was prescribed, but it made her feel drugged and upon discontinuation she had withdrawal effects. Another family practice physician diagnosed “nonspecific anxiety disorder” and began buspirone; an experience she describes as “having an alien try to climb out of my skin.” Buspirone was discontinued. Paroxetine was tried for 8 weeks with no effect. Finally, a psychiatrist was consulted, who diagnosed adult attention-deficit disorder (without hyperactivity) and suggested treatment with methylphenidate. At this point, the patient was convinced that a stimulant would not help her insomnia and demanded referral to a sleep disorders center.


Ms. W’s symptoms fall into the broad category of an insomnia, and the symptoms began after having moved from one city to another. Environmental sleep disorder (noise) and adjustment sleep disorder (new

job, city, and apartment) are likely initial diagnoses. However, a more chronic, endogenous problem has become operative. What is it? Ms. W is a “worrier” and meticulous, but she doesn’t reach diagnostic criteria for personality or anxiety disorders. Dyssomnia associated with mood disorder should be considered in any patient with sleep maintenance problems and early morning awakening insomnia. However, this patient does not have other significant signs of depression. Unfortunately, many patients are misdiagnosed with depression or “masked depression” on the sole basis of an insomnia complaint and unsuccessfully treated with antidepressant medication. Ms. W’s job demands long hours with focused concentration. Her job performance has been superior for many years notwithstanding insomnia. Thus, a diagnosis of attention-deficit disorder is unlikely. Idiopathic insomnia implies a childhood complaint, which Ms. W denies.

The likely working diagnosis is PPI. There may be some sleep state misperception (sometimes unclear of whether she is awake or asleep), but this cannot adequately account for the constellation of symptoms. An initial treatment plan should include further documentation of the sleep pattern using a sleep log. Behavioral treatments will likely benefit this patient. Medications with sedative effects are sometimes useful during initial treatment of PPI. However, thus far in this patient they have done more harm than good. She is likely to be a challenging patient to treat. 

Idiopathic Insomnia. Idiopathic insomnia characterizes patients with a lifelong inability to obtain adequate sleep. The insomnia predates any psychiatric condition, and other etiologies must be ruled out or treated, including PPI, environmental sleep disturbances, and poor sleep hygiene.

Paradoxical Insomnia. Paradoxical insomnia, at its core, involves a dissociation between sleep and its usual attendant unconsciousness. In paradoxical insomnia, a person thinks he or she is awake and having insomnia even though the brain electrophysiologic activity pattern is consistent with the correlates of healthy sleep. We should consider this disorder when a patient complains of difficulty initiating or maintaining sleep without any objective evidence of sleep disruption. Paradoxical insomnia can occur in individuals who are free from psychopathology; however, it may represent a somatic delusion or hypochondriasis. Some patients with paradoxical insomnia have obsessional features regarding bodily functions.

Inadequate Sleep Hygiene. Inadequate sleep hygiene refers to insomnia produced by behaviors that are not conducive to good sleep. Many behaviors can interfere with sleep. Some of these behaviors increase arousal, for example, consuming caffeine or nicotine at night or engaging in excessive emotional or physical stimulation within a few hours of bedtime. Other behaviors interfere with sleep architecture, including daytime naps and a significant variation of the daily sleep–wake schedule.

Behavioral Insomnia of Childhood. Children with this subtype of insomnia depend on specific stimulation, objects, or setting for initiating or returning to sleep. Without the presence of, for example, a stuffed animal or a parent, the child has trouble falling asleep. Alternatively, without adequate limit-setting by the caregiver, bedtime stalling (“Dad, I’m thirsty—can I get some water?”) or bedtime refusal (“I’m not tired! I don’t want to go to sleep!”) can ensue.

Insomnia Comorbid with Mental Disorder. This type of insomnia is the most common. Sleep disorder centers report that 35 percent of patients seen with insomnia have a mental disorder. Of these, major depressive disorder (MDD) is the most common disorder. Other common disorders include bipolar disorder, schizophrenia, and generalized anxiety disorder.

Insomnia Comorbid with Medical Condition. Insomnia accompanies many medical and neurologic conditions. Given pain’s potential for disturbing sleep, all medical conditions producing pain can (and usually do) disturb sleep. Unfortunately, a synergy exists between pain and sleep, such that poor sleep lowers the pain threshold. This vicious cycle can present a difficult treatment challenge. However, reducing pain can also improve sleep,

and improving sleep can reduce pain. In other medical conditions, sleep disturbance appears to be secondary. For example, patients with sleep-related gastroesophageal reflux disease (GERD) often have insomnia. Treating the reflux results in sleep improvement but insomnia treatments seldom, if ever, relieve nocturnal GERD. Patients with chronic obstructive pulmonary disease (COPD) commonly suffer from both sleep-onset and sleep-maintenance insomnia. Neurodegenerative disorders are also frequently associated with sleep disorders.

Insomnia due to Drug or Substance. Many prescription drugs, even when taken properly, can disturb sleep. We list some common examples in Table 15-7.

Alcohol and hypnotic use initially promote sleep onset because of their sedating properties. A problem occurs when sleep quality is adversely affected, tolerance develops after chronic use, or withdrawal begins. Alcohol may relax a tense person and thereby decrease latency to sleep; however, sleep later in the night will usually be fragmented by arousals. As tolerance develops to the alcohol, higher amounts or more frequent dosing are needed to sustain the effects. Furthermore, during withdrawal or after tolerance develops, insomnia may rebound to a level more severe than the initial disturbance.

Caffeine (the active ingredient in coffee) and theobromine (the active ingredient in chocolate) are methylxanthines and act as psychostimulants in the central nervous system (CNS). Psychostimulants increase sleep latency, reduce sleep efficiency, and decrease total sleep time. Caffeine’s half-life is 3 to 7 hours and may interfere with sleep when consumed in large quantities throughout the day or even in smaller portions closer to bedtime. Some individuals are hypersensitive to methylxanthines, and any coffee or chocolate can trigger difficulty falling asleep or awakening after a couple of hours of sleep with difficulty getting back to sleep.

Finally, abuse of illicit substances, particularly stimulants (such as cocaine and amphetamines), interfere with sleep onset and sleep maintenance. Unlike with alcohol, discontinuation of these substances will cause hypersomnolence.

Hypersomnolence Disorder

DSM-5 includes hypersomnolence disorder as a discreet diagnosis, whereas ICSD and ICD consider it more broadly. ICSD refers to it as “idiopathic hypersomnia” and questions whether it is a single disorder or rather a group of disorders with different underlying causes. Table 15-8 compares the different approaches to diagnosing hypersomnolence.

In general, we should consider this disorder when a patient complains of frequently feeling sleepy despite getting adequate sleep. They may nap during the day. Despite getting adequate sleep, they do not feel refreshed when waking.

Kleine–Levin Syndrome. Kleine–Levin syndrome is a relatively rare condition consisting of recurrent periods of prolonged sleep (from which they are arousable) with intervening periods of healthy sleep and alert waking. During the episodes of hypersomnia, wakeful periods are usually marked by withdrawal from social contacts and return to bed at the first opportunity. Kleine–Levin syndrome is the best-recognized recurrent hypersomnia though it is uncommon. It predominantly afflicts males in early adolescence; however, it can also affect females and older people. With few exceptions, the first attack occurs between the ages of 10 and 21 years. However, there are some reports of onset in the fourth and fifth decades of life. In its classic

form, the recurrent episodes include extreme sleepiness (18- to 20-hour sleep periods), voracious eating, hypersexuality, and disinhibition (e.g., aggression). Episodes typically last for a few days up to several weeks and appear once to 10 times per year. A monosymptomatic hypersomnolent form can occur. The disorder is usually sporadic but familial cases are reported.


Table 15-9 lists the criteria for narcolepsy. People with narcolepsy have irresistible sleep episodes, lapses into sleep, or nap frequently.

The discovery that narcolepsy is strongly associated with a hypocretin (orexin) deficit radically changed diagnostic practice. Cataplexy had been considered a core feature of the disorder, but we now know that there are variants that occur without cataplexy.

Sleep-Related Breathing Disorders

DSM-5 includes three disorders under the category of sleep-related breathing disorders: obstructive sleep apnea-hypopnea, central sleep apnea, and sleep-related hypoventilation. Table 15-10 compares the diagnostic approaches to sleep-related breathing disorders.

Sleep Wake Disorders Sleep Wake Disorders Reviewed by Web of Psychiatry on December 07, 2021 Rating: 5

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