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Sleep Disorders
Sleep Disorders
Julie S. Young MD, MS
Kimberly A. Hardin MD, MS, FAASM
A 48-year-old man who has been sober for 6 weeks comes to the ambulatory care clinic saying he hasn’t “slept a wink” since entering a residential treatment program 4 weeks ago. He stopped drinking alcohol “cold turkey” after his wife of 20 years and two daughters left him due to the patient’s refusal to quit drinking. For the past 20 years, he has drank up to one 12 pack of beer nightly and could not fall asleep unless he drank at least two beers before bedtime.
CLINICAL HIGHLIGHTS
Insomnia affects more than 30% of the general population.
Insomnia may present as a symptom of an underlying psychiatric, medical, or substance- or medication-related condition.
Evaluation of a sleep complaint should include a complete assessment of general medical, psychiatric, and substance misuse-related symptoms. Inquires about sleep hygiene as well as current prescribed and over-the-counter medications should also be initiated.
The treatment of primary insomnia is multifactorial and should include a stepwise approach that addresses sleep hygiene and environmental factors before considering prescription sleep medications.
Women may have more pronounced sleep disturbance and require additional treatment related to hormonal status.
Benzodiazepines and anticholinergic agents should be used cautiously in elderly patients.
Clinical Significance
Many sleep disorders can adversely affect patient health. Insomnia is widely prevalent and the most commonly encountered sleep disorder in the primary care setting. Although the focus of this chapter is on insomnia, other sleep disorders such as obstructive sleep apnea-hypoapnea (OSAH) and restless leg syndrome (RLS) will be discussed within the context of exploring a differential diagnosis for insomnia.
Insomnia affects greater than 30% of adults in the United States (1, 2). Patient surveys have found that primary care patients with insomnia have 60% higher overall health care costs than those without insomnia. The annual indirect and direct economic burden of insomnia in the U.S. has been estimated to be about $100 billion (3).
Prolonged periods of disrupted sleep can lead to sleep deprivation, or a chronic lack of restorative sleep, which has numerous physical and psychological consequences. Chronic sleep deprivation is associated with hypertension, increased sympathetic cardiovascular activation, blunted hypothalamic-pituitary-adrenal axis function, impaired host defenses, and altered cognitive functioning (4). Inadequate sleep also increases the risk of developing anxiety and mood disorders. Patients with alcohol dependence in remission and comorbid chronic insomnia have a heightened risk of relapse. In sum, insomnia is independently associated with poor health-related quality of life (5).
Diagnosis
Insomnia can lead to cognitive, emotional, and motor dysfunction. The severity of insomnia is determined by the extent to which the sleep problem affects daytime function and is classified as mild, moderate, or severe. Mild insomnia does not cause daytime dysfunction; moderate insomnia usually causes some daytime dysfunction; and severe insomnia results in obvious global impairment in daytime functioning. Insomnia is also described by length of symptoms (acute insomnia lasts <3 months, subacute insomnia is present for 3-6 months, and chronic insomnia persists for 6 or more months).
Consequences of impaired cognition include inattentiveness, distractibility, and carelessness. Healthy individuals become prone to mood lability, irritability, decreased frustration tolerance, depressed mood, and anxiety. Motor dysfunction can range from a clinically insignificant decline in fine motor control to an inability to safely operate a motor vehicle.
Despite its impact on overall health and well-being, sleep is often not addressed during routine health visits. Primary care providers do not usually screen for sleep-related problems and patients do not normally bring up the topic unless symptoms are severe. Sleep should be a routine part of the review of systems for all patients who complain of nonspecific symptoms such as fatigue, lethargy, worsening cognitive status, anxiety, or changes in mood. Before pursuing less common paths of diagnostic inquiry, ask about sleep early in the interview. Not realizing the significance of sleep to their overall health, patients with even extremely poor sleep may complain about everything but sleep, leading you to unnecessary questioning about multiple somatic disorders before you get to the real culprit, disrupted sleep.
A sleep disorder may be diagnosed by using one of four classification systems, each of which includes varying levels of diagnostic precision. The most detailed classifications are the International Classification of Sleep Disorders (ICSD-2) and the Diagnostic Classification of Sleep and Arousal Disorders (DCSAD), both of which are primarily used by sleep specialists (6, 7). The World Health Organization’s International Classification of Diseases (ICD-10) (8) includes a more restricted list of specific sleep disorders, but is commonly used in clinical medicine for billing purposes. Although commonly used by psychiatrists, the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, text revision (DSM-IV-TR) are rarely used by sleep specialists and sleep researchers due to the broad acceptance of existing nosology in the field of sleep medicine, and more importantly, due to its relatively limited scope. ICSD-2 criteria will be used in this chapter (Table 13.1).
Differential Diagnosis
The ICSD-2 lists 10 types of insomnias. These insomnias vary by etiology and require the persistence of difficulty initiating or maintaining sleep and at least one of nine symptoms of daytime impairment such as fatigue, impaired concentration, or mood irritability. The insomnias can be divided into extrinsic and intrinsic insomnias (Table 13.2). Extrinsic insomnias are due to factors that are external to the patient, while intrinsic insomnias are due to factors that are inherent to the patient.
Table 13.1 General Criteria for the Diagnosis of Insomnia
1. Difficulty initiating or maintaining sleep, awakening too early, nonrestorative or poor quality of sleep
2. Sleep difficulty occurs despite adequate opportunity and circumstances for sleep
3. At least one of the following forms of daytime impairment related to the nighttime sleep difficulty occurs:
Fatigue or malaise
Attention, concentration, or memory impairment
Social or vocational dysfunction or poor school performance
Mood disturbance or irritability
Daytime somnolence
Motivation, energy, or initiative reduction
Prone to errors or accidents at work or while operating a car or other machinery
Muscle tension, headaches, or gastrointestinal symptoms
Preoccupation with sleep or lack of sleep
Adapted from American Sleep Disorders Association, Diagnostic Classification Steering Committee. International Classification of Sleep Disorders: Diagnostic and Coding Manual. Westchester, IL: American Academy of Sleep Medicine; 2005.
EXTRINSIC INSOMNIAS
Adjustment Insomnia
In a 1-year period, approximately 15% to 20% of the adult population experience adjustment insomnia, or acute insomnia, which lasts less than 3 months. The diagnosis of adjustment insomnia requires the presence of an identifiable stressor, which may be psychological (e.g., death of a loved one), interpersonal (e.g., divorce), or environmental (e.g., moving to a new home). Adjustment insomnia usually resolves after the resolution of or adjustment to a stressor. A brief course of a sedative-hypnotic medication coupled with a referral for supportive psychotherapy may be an effective treatment approach.
Inadequate Sleep Hygiene
Sleep hygiene refers to behaviors and activities that promote sleep and discourage wakefulness. The diagnostic criteria for inadequate sleep hygiene, a type of insomnia, includes meeting the criteria for insomnia as listed in Table 13.1 for at least 1 month and the presence of at least one of the following: (1) sleep schedule that consists of frequent daytime naps, highly variable bedtimes or rising times, or excess time spent in bed; (2) routine use of alcohol, nicotine, or caffeine, especially preceding bedtime; (3) engaging in mentally stimulating, physically activating, or emotionally upsetting activities close to bedtime; (4) frequent use of bed for activities other than sleep (e.g., watching television); and (5) lack of a comfortable sleeping environment (e.g., too noisy).
From American Sleep Disorders Association, Diagnostic Classification Steering Committee. International Classification of Sleep Disorders: Diagnostic and Coding Manual. Westchester, IL: American Academy of Sleep Medicine; 2005.
Insomnia Due to a Medical Condition
Medical illnesses associated with insomnia are numerous and include common chronic medical disorders (e.g., diabetes or heart failure) to other more reversible systemic conditions (e.g., anemia or a thyroid disorder). Neurologic conditions like dementia, seizures, or stroke make up another major category. Poststroke patients have an increased risk of developing OSAH during the first several months after the stroke. In addition to insomnia, poststroke patients have an increased risk of developing hypersomnia, which is associated with prolonged sleep episodes or daytime sleepiness. Parkinson disease and Alzheimer disease are associated with sleep disturbances such as rapid eye movement (REM) sleep behavior disorder (RBD), which is characterized by intermittent episodes of elaborate motor activity where dreams may be acted out during REM sleep.
Insomnia Due to Medications and Substances
Multiple drugs can alter sleep quantity and quality. Sedatives and opioids may initially help with sleep onset, but impair sleep architecture and ultimately lead to insomnia. Sedative-hypnotics themselves can disrupt sleep by causing rebound insomnia during withdrawal. Withdrawal from or intoxication with alcohol, marijuana, or other illicit drugs can also cause abnormal sleep patterns. Sleep disturbances may persist for up to 1 to 2 years after ceasing substance use. Table 13.3 lists common medications associated with insomnia.
INTRINSIC INSOMNIAS
Insomnia Due to a Mental Disorder
Insomnia due to a mental disorder is the most common type of insomnia encountered in sleep centers. Several mood, anxiety, psychotic, and neurodevelopmental disorders are associated with sleep problems, and include insomnia as a feature of the disorder. While the many symptoms of psychiatric disorders often vary, sleep disturbance is a common complaint that is more likely to be reported to providers. Table 13.4 lists sleep characteristics among patients with various psychiatric conditions.
Psychophysiologic Insomnia
Psychophysiologic insomnia is characterized by psychological and physiologic hyperarousal at bedtime and occurs in 1% to 2% of the population. Individuals with psychophysiologic insomnia, also known as learned or conditioned insomnia, are preoccupied with sleep, and often require a combination of behavioral and pharmacologic therapies. The diagnostic criteria for psychophysiologic insomnia include meeting the criteria for insomnia in Table 13.1 for at least 1 month. The patient must also have evidence of conditioned sleep difficulties or hyperarousal at bedtime such as (1) preoccupation and anxiety about sleep; (2) difficulty falling asleep in bed at the desired time, but no difficulty falling asleep during monotonous activities when not intended; (3) sleeping better when away from home; (4) mental arousal characterized by intrusive thoughts; and (5) heightened somatic tension in bed reflected by a perceived inability to relax the body sufficiently to allow the onset of sleep.
Psychophysiologic insomnia differs from adjustment insomnia in its longer duration and lack of a current identifiable stressor. While attempting to fall asleep, those with psychophysiologic insomnia worry excessively about sleep, in contrast to those with generalized anxiety disorder, who tend to ruminate about multiple life stressors. Patients with psychophysiologic insomnia often report improved sleep when varying their bedtime routine or when sleeping in an unfamiliar environment. Those with psychophysiologic insomnia may complain of an inability to “stop thinking” or of “racing thoughts.” This is in contrast to thought patterns seen in a manic episode, when thoughts are sped up and difficult to track (flight of ideas), are extremely rapid (racing thoughts), and may include grandiose themes. A patient with mania will not likely complain of daytime fatigue due to sleeplessness.
Table 13.4 Characteristics of Sleep in Various Psychiatric Diagnoses
