Chapter 14

Sleep Disorders

Sleep Disorders: DSM-5

• Sleep disorders are categorized into 10 disorders or disorder groups:(1) Insomnia disorder*(2) Hypersomnolence disorder*(3) Narcolepsy*(4) Breathing-related sleep disorders(5) Circadian rhythm sleep–wake disorders(6) Non-rapid eye movement (NREM) sleep arousal disorder*(7) Nightmare disorder*(8) Rapid eye movement (REM) sleep behavior disorder*(9) Restless legs syndrome(10) Substance-/medication-induced sleep disorder* Reviewed in this chapter

Neuroscience of Sleep

• Polysomnography• Electroencephalography (EEG)– Brainwaves as defined by amplitude, frequency,

and form• Electro-oculography (EOG)– Measures movement of the eye

• Electromyography (EMG)– Measure muscle tone and activity

Types of Sleep

• Rapid eye movement (REM)– Dreaming occurs – Brain waves very similar to wakefulness

• Non-rapid eye movement (non-REM)– Any sleep state that is not REM sleep– Four stages • Criteria for stages 3 and 4 sleep have been combined

into a single category

Sleep Stages

• Stage 1/N1 – The transition from wakefulness to sleep– Takes 15 to 20 minutes to move from this stage to the next

• Stage 2/N2 – Stage of sleep associated with a predominance of theta waves

with the appearance of highly characteristic sleep spindle and K-complex wave forms

– Takes 30 to 50 minutes to move from this stage to the next• Stages 3–4/N3

– Known as deep sleep, slow-wave sleep, or delta sleep– Reports of dreams are infrequent and the images are much

less vivid compared to dreams emerging from REM sleep

Sleep Stages cont.

• The proportion of time for an adult in each of these types and phases of sleep:– 25% REM and 75% non-REM sleep– Stage 1 (N1) (5%)– Stage 2 (N2) (45%)– Stage 3/4(N3) or slow-wave sleep (25%)

• Abnormalities in timing, distribution, and/or proportion of different types and phases are found in sleep disorders and psychiatric conditions (such as depression)

Multiple Sleep Latency Test (MSLT)

• Measure of daytime sleepiness• Consists of four to five distinct 20-minute

sessions, separated by 2-hour intervals• Done in sleep lab; individual asked to take a nap• First nap period begins within 3 hours after

waking• Purpose is to determine sleep latency and the

presence of REM sleep• Appearance of sleep within 20 minutes is

suggestive (but not diagnostic) of narcolepsy

Actigraphy

• Objective, noninvasive, and relatively cost-effective means of estimating sleep–wake patterns

• Movement data is used to determine sleep and wake periods

• Common variables include:– Total sleep time– Sleep-onset latency– Wake time after sleep onset– Sleep efficiency

Disorders of Inadequate/Excessive Sleep

• Insomnia disorder• Hypersomnolence• Narcolepsy– Much less prevalent in the general population– Commonly comorbid with affective and other

types of psychopathology

Sleep Disorder Criteria• For all sleep disorders:– Sleep disturbance (or associated daytime fatigue)

causes clinically significant distress or impairment in social, occupational, or other important areas of functioning

– Do not occur exclusively during the course of another mental disorder (e.g., depression, posttraumatic stress disorder) and are not due to the direct physiological effects of a substance (e.g., drug of abuse, medication) or a general medical condition

Insomnia Disorder• Predominant complaint of dissatisfaction with sleep

quantity or quality, associated with:– Difficulty initiating sleep– Difficulty maintaining sleep (frequent awakenings)– Early-morning awakening with inability to return to

sleep• At least 3 nights per week; for at least 3 months• Despite adequate opportunity for sleep• The sleep disturbance does not occur exclusively

during the course of narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia

Insomnia Disorder cont.

• Insomnia is the most prevalent of all sleep disorders in the general population and in those who are seeking treatment from primary care or mental health professionals

• 20% prevalence rate in general population• More prevalent in women and older patients• Commonly a comorbid condition with a medical

or psychiatric disorder• 50% meet criteria for mental health diagnosis,

usually anxiety or depression

Hypersomnolence• Self-reported excessive sleepiness despite a main

sleep period lasting at least 7 hours and at least one of the following:– Recurrent sleep periods within the same day– More than 9 hours of sleep that is nonrestorative– Difficulty being fully awake after abrupt awakening

• At least 3 nights per week; for at least 3 months• The somnolence does not occur exclusively

during the course of narcolepsy, breathing-related sleep disorder, circadian rhythm sleep disorder, or a parasomnia

Hypersomnolence cont.

• 5% to 10% of patients who seek treatment for excessive daytime sleepiness suffer from hypersomnolence disorder

• Estimated to affect 1% of U.S. and European populations

• Males and females are equally affected• Onset is often progressive with mean age of

onset between 15 and 25 years of age

Narcolepsy• Recurrent periods of irrepressible need to sleep, lapsing into

sleep, or napping occurring within the same day, occurring at least three times per week over the past 3 months

• The presence of one of the following:- Episodes of cataplexy, defined as either:

• In individuals with long-standing disease, episodes of sudden bilateral loss of muscle tone with maintained consciousness that are precipitated by laughter or joking

• In children or in individuals within 6 months of onset, spontaneous grimaces or jaw-opening episodes with tongue thrusting or a global hypotonia, without any obvious emotional triggers

- Hypocretin deficiency, as measured using cerebrospinal fluid (CSF) - Nocturnal sleep polysomnography showing REM sleep latency less than or equal to 15 minutes, or a MSLT showing a mean sleep latency less than or equal to 8 minutes and two or more sleep-onset REM periods

Narcolepsy cont.

• Prevalence of classic narcolepsy with emotion-triggered cataplexy is approximately .02% to .05%

• Equal incidence in men and women• Approximately 30% of narcoleptics suffer from

excessive daytime sleepiness and sleep-onset REM but have no history of cataplexy

• Approximately 20% report sleep paralysis upon falling asleep or awakening

• Associated with insomnia

Diagnostic Considerations

• DSM-5 criteria for insomnia and hypersomnolence disorders include co-occurring medical, psychiatric, and/or other sleep disorders as unique specifiers (rather than exclusions for diagnosis as in DSM-IV)

• Comorbidity: Up to 70% of patients with GAD have insomnia; hypersomnolence and depression are highly associated (bidirectional)

• Kleine-Levin syndrome• Narcolepsy commonly occurs with depressive symptoms• Other sleep problems (circadian rhythm sleep–wake

disorder; restless legs syndrome)

Psychological and Biological Assessment

• PSG not usually used for insomnia diagnosis• Typically, sleep logs and actigraphy are used to

assess total sleep time, sleep onset latency, and number of awakenings

• PSG used for hypersomnia: Usually shows decreased sleep latency, increased total sleep time, normal or increased efficiency

• MSLT used for narcolepsy; measuring for hypocretin deficiency in CSF is most useful

Etiological Considerations

• Up to 50% of insomnia patients meet criteria for comorbid mental health diagnosis, usually anxiety or depression

• Onset in childhood is prognostic for later mental illness and adult sleep problems

• Several neurotransmitter systems are involved in arousal• Some individuals with hypersomnolence have a family

history of the disorder• Somnolence may result from viral infection or TBI• Lesions in the frontal and occipital lobes, hippocampus,

and amygdala have been associated with hypersomnia

Etiological Considerations cont.

• More than 86% of obese patients with type 2 diabetes have breathing-related sleep disorders

• Shift work, time zone changes, certain medications and changes in routines may result in circadian rhythm sleep disorders

• Familial patter of restless legs syndrome has been shown; 83% concordance rate in monozygotic twins

Parasomnias• According to DSM-5, parasomnias are

characterized by abnormal behavioral, experiential, or physiological events that occur in association with sleep or emerge during a specific sleep stage or during sleep-wake transitions

• Most common are non–REM sleep arousal disorders and REM sleep behavior disorder, which represent admixtures of wake and sleep

• Often come to the attention of mental health providers due to the associated bizarre, wild, and sometimes dangerous behaviors

Nightmare Disorder

• Repeated occurrences of extended, extremely dysphoric, and well-remembered dreams that usually involve efforts to avoid threats to survival, security, or physical integrity

• Occurs almost exclusively during REM sleep and thus more likely to occur during the second half of the sleep period

• On awakening, individual rapidly becomes oriented and alert

Nightmare Disorder cont.

• Nightmares are fairly common in childhood • About 6% of adults have one nightmare per

week• Only 1% to 2% have more frequent nightmares• Peak ages are 10 to 29 for women; 30 to 49

for men• Highly associated with PTSD• May produce clinically significant insomnia

Non-REM Sleep Arousal Disorders• Repeated occurrence of incomplete arousals from non-REM

sleep; usually occurring during the first third of the nighttime sleep episode; typically brief (10 minutes – 1 hour), accompanied by one of the following:– Sleepwalking: Repeated episodes of rising from bed during sleep and

walking about; while sleepwalking, the person has a blank, staring face, is relatively unresponsive to the communication efforts of others to communicate, and can be awakened only with great difficulty

– Sleep terrors: Recurrent episodes of abrupt terror arousals from sleep, usually beginning with a panicky scream; intense fear and autonomic arousal is present (tachycardia, rapid breathing, sweating); relatively unresponsive to efforts of others to comfort

• Little or no dream image is recalled• Amnesia for the episode is present

Non-REM Sleep Arousal Disorders cont.

• 10% to 30% of children have at least one sleepwalking episode and 2% sleepwalk often

• Prevalence is lower in adults (1–7%)• Sleep terrors more common in children• 20% young children, with 4% to 5%

experiencing one or more episodes per week• 75% of patients with sleep terrors will report

sleepwalking

REM Sleep Behavior Disorder• Repeated episodes of arousal during sleep associated with

vocalization and/or complex motor behaviors• Behaviors arise during REM sleep and therefore usually

occur more than 90 minutes after sleep onset; more frequent during the later portions of the sleep period; uncommon during daytime naps

• Upon awakening from the episode, the individual is completely awake, alert, and not confused or disoriented

• Either of the following:– REM sleep without atonia on PSG recording– History suggestive of REM sleep behavior disorder and an

established synucleinopathy diagnosis (e.g., Parkinson’s disease)

REM Sleep Behavior Disorder cont.

• Usually appears in adulthood• Men over age 50 most likely to be affected• When diagnosis is made earlier, 1:1 gender• Best prevalence estimate is 0.5% in general

population• Often able to recall dream content• Usually noticed when it causes danger to the

patient• Comorbid narcolepsy occurs in approximately 30%

of cases

Psychological and Biological Assessment

• Patients with recurrent nightmares tend to have fewer nightmares when evaluated in sleep lab (safety cues); sleep parameters are not much different from controls

• EEG patterns are used to evaluate individuals with sleep terrors and sleepwalking

• REM sleep behavior disorder can be evaluated with a combination of PSG and video monitoring

• Sleep paralysis • Sleep panic attacks

Etiological Considerations• Genetic influence on nightmares has been found to account for

an estimated 45% of the phenotypic variance in childhood and 37% in adulthood

• Pedigree studies suggest a very high rate of heritability for sleep terrors (as well as sleep terror and sleepwalking comorbidity)

• No genetic test for REM sleep behavior disorder; observations support brainstem abnormalities in the underlying pathophysiology

• REM sleep behavior disorder may present years before medical disorders (Parkinson’s disease)

• Lesions or dysfunction in REM sleep and motor control circuitry in the pontomedullary structures is hypothesized to explain REM sleep behavior disorder years or decades before the onset of neurogenerative disease