Sleep-Wake Disorders are a group of conditions that affect the quality, timing, and duration of sleep, leading to distress or impaired functioning. These disorders are classified in the *Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5)* and the *International Classification of Sleep Disorders (ICSD-3)*.

Major Categories of Sleep-Wake Disorders

1. Insomnia Disorder

  • Symptoms: Difficulty falling asleep, staying asleep, or waking too early, despite adequate opportunity for sleep.
  • Effects: Daytime fatigue, mood disturbances, cognitive impairment.
  • Types:
    • Short-term (Acute) Insomnia – Lasts <3 months, often due to stress.
    • Chronic Insomnia – Occurs ≥3 nights/week for ≥3 months.

2. Hypersomnolence Disorders

  • Excessive daytime sleepiness despite sufficient nighttime sleep.
  • Examples:
    • Narcolepsy (Type 1 with cataplexy, Type 2 without cataplexy).
    • Idiopathic Hypersomnia (chronic excessive sleep without a clear cause).

3. Circadian Rhythm Sleep-Wake Disorders

  • Misalignment between sleep-wake cycles and environmental demands.
  • Subtypes:
    • Delayed Sleep Phase Type (night owls, difficulty waking early).
    • Advanced Sleep Phase Type (early sleepers, waking too early).
    • Shift Work Disorder (disruption due to work schedules).
    • Irregular Sleep-Wake Type (fragmented sleep, common in dementia).

4. Parasomnias

  • Abnormal behaviors or experiences during sleep.
  • Examples:
    • REM Sleep Behavior Disorder (acting out dreams, linked to Parkinson’s).
    • Sleepwalking (Somnambulism).
    • Nightmare Disorder (disturbing dreams causing awakenings).
    • Sleep Terrors (intense fear, screaming during non-REM sleep).

5. Sleep-Related Breathing Disorders

  • Obstructive Sleep Apnea (OSA) – Blocked airway causing pauses in breathing.
  • Central Sleep Apnea – Brain fails to signal breathing muscles.

6. Restless Legs Syndrome (RLS) & Periodic Limb Movement Disorder (PLMD)

  • RLS: Urge to move legs due to discomfort, worse at night.
  • PLMD: Repetitive limb movements during sleep.

Causes & Risk Factors

  • Medical: Chronic pain, asthma, neurological conditions.
  • Psychiatric: Depression, anxiety, PTSD.
  • Lifestyle: Shift work, caffeine, poor sleep hygiene.
  • Genetic Factors (e.g., narcolepsy with cataplexy linked to HLA-DQB1*06:02).

Treatment Approaches

  • Cognitive Behavioral Therapy for Insomnia (CBT-I) – Gold standard for chronic insomnia.
  • Medications:
    • Insomnia: Z-drugs (zolpidem), melatonin agonists (ramelteon).
    • Narcolepsy: Stimulants (modafinil), sodium oxybate.
  • Light Therapy (for circadian rhythm disorders).
  • CPAP/BiPAP (for sleep apnea).
  • Lifestyle Modifications: Sleep hygiene, regular sleep schedule, avoiding caffeine/alcohol before bed.

When to See a Doctor

  • Persistent sleep problems affecting daily life.
  • Excessive daytime sleepiness, snoring with breathing pauses (possible apnea).
  • Unusual behaviors during sleep (e.g., acting out dreams).