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Psychiatry: Sleep-Wake Disorders (Pearls)

Quick Cram Summary Table — Sleep-Wake Disorders (click to open)
SLEEP-WAKE DISORDERS
Circadian rhythm sleep-wake disorders
Patient will present as → a 17-year-old high school junior brought in for falling asleep in first period. He lies awake until 3 AM every night and cannot get up for school at 6:30 AM. On weekends and school breaks he sleeps from 3 AM to noon and wakes refreshed. He does not snore, and his mood is good.
The body clock is out of step with the schedule life demands — sleep itself is normal when the patient picks the hours

  • Delayed sleep phase — the "night owl"; falls asleep late and wakes late; most common type, classic in adolescents and young adults
  • Advanced sleep phase — sleepy in the early evening and awake at 3 to 5 AM; classic in older adults
  • Shift work type — poor sleep during the day and sleepiness during the night shift
  • Non-24-hour type — sleep time drifts later each day; classic in totally blind patients (no light signal to reset the clock)
  • Tell it from insomnia: in insomnia the patient cannot sleep even with a free schedule

DX: Clinical — sleep diary, with actigraphy if available, for at least 1 to 2 weeks

  • A sleep study is not needed unless another sleep disorder (such as sleep apnea) is suspected

TX: Reset the clock with timed bright light and melatonin

  • Delayed phase: bright light in the morning + low-dose melatonin in the evening; avoid screens and bright light at night
  • Advanced phase: bright light in the evening
  • Shift work: planned naps and bright light during the shift; modafinil or armodafinil for sleepiness on shift
  • Non-24-hour in blind patients: a melatonin receptor agonist (tasimelteon)
Hypersomnolence
Patient will present as → a 24-year-old graduate student who sleeps 10 to 11 hours a night and still feels exhausted. She sleeps through several alarms and is confused and groggy for an hour after waking. She takes 2-hour naps that do not refresh her. She does not snore, has never gone weak with laughter, and takes no medications.
Excessive sleepiness despite a full night of sleep (at least 7 hours)

  • Shows up as repeated lapses into sleep, a long main sleep (more than 9 hours) that does not restore, or great difficulty waking fully ("sleep drunkenness")
  • Naps are long and unrefreshing — narcolepsy naps are short and refreshing
  • No cataplexy
  • First rule out the common causes of daytime sleepiness: too little sleep, obstructive sleep apnea, sedating drugs or alcohol, and depression
  • Kleine-Levin syndrome — rare; young men with episodes of days of sleep plus overeating and hypersexuality

DX: DSM-5-TR — sleepiness despite ≥ 7 hours of sleep, at least 3 times a week for at least 3 months, with distress or impairment

  • Overnight sleep study to exclude sleep apnea, then a multiple sleep latency test
  • Short sleep latency (≤ 8 minutes) with fewer than 2 sleep-onset REM periods — 2 or more points to narcolepsy

TX: Modafinil is first-line

  • Alternatives: stimulants (methylphenidate) or oxybate
  • Keep a regular sleep schedule; avoid alcohol and sedating medications
Insomnia
Patient will present as → a 39-year-old woman with 4 months of lying awake for over an hour most nights and waking several times before morning. She feels tired and irritable and is making mistakes at work. She spends 9 hours in bed, watches the clock, and drinks coffee until 4 PM. She does not snore, and her mood is otherwise good.
Trouble falling asleep, staying asleep, or waking too early — with daytime consequences

  • At least 3 nights a week for at least 3 months, despite enough opportunity to sleep
  • Must cause daytime impairment — fatigue, poor concentration, irritability
  • Often travels with depression and anxiety — early morning awakening suggests depression; treat both
  • Look for fixable causes: caffeine, alcohol, stimulants, pain, nocturia, sleep apnea, restless legs

DX: Clinical — history plus a sleep diary

  • A sleep study is not routine — order one only if sleep apnea or a parasomnia is suspected

TX: Cognitive behavioral therapy for insomnia (CBT-I) is first-line — works as well as medication, and the benefit lasts

  • CBT-I = stimulus control (bed only for sleep; get up if awake 20 minutes), sleep restriction, fixed wake time, relaxation, sleep hygiene
  • Medication is a short-term add-on: zolpidem, eszopiclone or zaleplon; low-dose doxepin for staying asleep; ramelteon for falling asleep (no abuse potential); orexin antagonists (suvorexant)
  • ⚠️ Avoid benzodiazepines and diphenhydramine in older adults — falls, confusion, dependence
Narcolepsy
Patient will present as → a 19-year-old college student with a year of irresistible sleep attacks in class; short naps leave her refreshed. Twice her knees buckled when she laughed hard, but she stayed awake. She sometimes wakes unable to move for a minute and sees figures in her room as she falls asleep.
Loss of orexin (hypocretin) neurons in the hypothalamus — REM sleep intrudes into wakefulness

  • Classic four: excessive daytime sleepiness, cataplexy, sleep paralysis, and hallucinations at sleep onset (hypnagogic) or on waking (hypnopompic)
  • Cataplexy = sudden loss of muscle tone triggered by emotion (laughter), with consciousness preserved — defines type 1
  • Onset is usually between ages 15 and 25; linked to HLA-DQB1*06:02
  • Naps are short and refreshing — in hypersomnolence disorder naps are long and unrefreshing

DX: Overnight sleep study followed by a multiple sleep latency test — mean sleep latency ≤ 8 minutes with 2 or more sleep-onset REM periods

  • The overnight study rules out sleep apnea; REM within 15 minutes of sleep onset counts as one sleep-onset REM period
  • Low CSF hypocretin-1 confirms type 1

TX: Scheduled daytime naps + a wake-promoting agent — modafinil or armodafinil first

  • Other options for sleepiness: solriamfetol, pitolisant, stimulants (methylphenidate, amphetamines)
  • Cataplexy: oxybate or pitolisant; antidepressants that suppress REM sleep (venlafaxine, tricyclics) are alternatives
Parasomnias
Patient will present as → a 6-year-old boy who sits up screaming about 90 minutes after falling asleep, sweating, with a racing heart. He does not respond to his parents, settles after 5 minutes, and remembers nothing in the morning.

Patient will present as → a 68-year-old man whose wife reports 6 months of punching and kicking in his sleep in the early morning hours. When woken, he is alert and describes a vivid dream of fighting off an attacker. Exam shows a mild resting tremor and reduced arm swing.
Abnormal behaviors during sleep — sort them by time of night and by whether the patient remembers

  • Sleepwalking and sleep terrors (NREM) — first third of the night, hard to wake, no memory of the event; common in children and usually outgrown
  • Sleep terror — sudden scream with sweating and tachycardia; the child cannot be comforted
  • Nightmare disorder (REM) — second half of the night; wakes fully alert and recalls the dream
  • REM sleep behavior disorder — acts out dreams because normal REM paralysis is lost; older men; injures self or bed partner
  • ⚠️ REM sleep behavior disorder often comes years before Parkinson disease or Lewy body dementia

DX: Clinical for sleepwalking, sleep terrors and nightmares

  • REM sleep behavior disorder needs a sleep study — shows REM sleep without atonia (muscle tone stays on during REM)
  • Sleep study with EEG if nocturnal seizures are possible

TX: Sleepwalking and sleep terrors: reassurance + a safe bedroom — do not try to wake the child; avoid sleep deprivation

  • REM sleep behavior disorder: make the bedroom safe first, then melatonin or clonazepam at bedtime
  • Nightmare disorder: image rehearsal therapy; prazosin may be used for PTSD-related nightmares
Psychiatry EOR: Voyeuristic disorder (Prev Lesson)
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