Insomnia Disorder

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Definition & Epidemiology - Counting Sheep No More

  • Insomnia: Difficulty initiating/maintaining sleep (DIS/DMS), early morning awakening (EMA), or non-restorative sleep, despite adequate opportunity.
    • Causes clinically significant distress/impairment.
  • Key Criteria:
    • Frequency: ≥3 nights/week.
    • Duration: ≥3 months (Chronic).
    • Episodic: ≥1 to <3 months.
  • Epidemiology:
    • Prevalence: Symptoms 10-30%; Disorder 6-10%.
    • ↑ women, older adults, comorbid conditions.

⭐ Insomnia is a significant risk factor for depression & anxiety disorders.

Etiology & Pathophysiology - Why So Awake?

  • Spielman's 3-P Model:
    • Predisposing factors: Hyperarousal (cognitive/physiological), genetic predisposition, anxious personality traits.
    • Precipitating factors: Acute stressors (medical/psychiatric illness, life events), substances (caffeine, alcohol), medications (e.g., steroids).
    • Perpetuating factors: Poor sleep hygiene, maladaptive behaviors (e.g., napping, ↑ time in bed), conditioned arousal to bedroom.
  • Neurobiological Factors:
    • ↑ Wake-promoting systems: Orexin/hypocretin, glutamate, cortisol (HPA axis dysregulation).
    • ↓ Sleep-promoting systems: GABAergic inhibition, altered melatonin secretion rhythm.
    • Brain: Hyperactivity in arousal circuits (e.g., Reticular Activating System, amygdala, prefrontal cortex). Factors in Insomnia Development

⭐ Insomnia is characterized by physiological and cognitive hyperarousal, not just at night but often persisting during the day, increasing comorbidity risks with mood and anxiety disorders.

Clinical Features & Diagnosis - Pinpointing the Problem

  • Core Features: Difficulty initiating/maintaining sleep, or early morning awakening with inability to return to sleep.

  • Occurs despite adequate opportunity for sleep.

  • Causes clinically significant distress/impairment (social, occupational).

  • Diagnostic Criteria (DSM-5 Summary):

    • Sleep difficulty ≥ 3 nights/week for ≥ 3 months.
    • Not better explained by another sleep-wake disorder.
    • Not attributable to substance effects (drug of abuse, medication).
    • Coexisting mental/medical conditions don't adequately explain predominant complaint of insomnia.

Key Diagnostic Tool: Sleep diary (at least 2 weeks) is crucial for assessing sleep patterns and variability before polysomnography consideration if diagnosis is uncertain or comorbid sleep disorders suspected (e.g., OSA, PLMD).

Non-Pharmacological Management - Mind Over Mattress

  • Cognitive Behavioral Therapy for Insomnia (CBT-I): First-line treatment.
    • Sleep Hygiene: Consistent sleep-wake schedule; avoid stimulants (caffeine, nicotine) & alcohol near bedtime; cool, dark, quiet room; limit naps (≤ 30 min).
    • Stimulus Control: Bed for sleep/sex only; leave bed if not asleep in 20 min, return when sleepy; fixed wake time.
    • Sleep Restriction: Limit time in bed to actual sleep time, then gradually increase as sleep efficiency improves (> 85%).
    • Relaxation Training: Progressive muscle relaxation, deep breathing, mindfulness.
    • Cognitive Therapy: Challenge dysfunctional beliefs about sleep. 10 Tips for Better Sleep

⭐ CBT-I is considered the gold standard and first-line treatment for chronic insomnia, often demonstrating superior long-term efficacy compared to pharmacotherapy alone.

Pharmacological Management - Pills for Peace

  • Indication: Short-term for moderate-severe insomnia; ideally alongside CBT-I.
  • Benzodiazepines (BZDs): e.g., Lorazepam. Rapid onset. Risks: tolerance, dependence, withdrawal. Use for <4 weeks.
  • Non-BZDs (Z-drugs): Zolpidem, Zaleplon, Eszopiclone. Better safety than BZDs but risk of complex sleep behaviors.
  • Melatonin Receptor Agonists: Ramelteon. Good for sleep-onset insomnia; no abuse potential.
  • Orexin Receptor Antagonists: Suvorexant, Lemborexant. Target wakefulness system.
  • Low-dose Sedating Antidepressants: Doxepin, Trazodone, Mirtazapine.

    ⭐ Z-drugs (Zolpidem, Zaleplon, Eszopiclone) selectively bind to α1 subunit of GABA-A receptor, leading to fewer anxiolytic/myorelaxant effects than BZDs.

High‑Yield Points - ⚡ Biggest Takeaways

  • Diagnosis: Sleep difficulty (initiation/maintenance/early awakening) ≥3 nights/week for ≥3 months, causing distress/impairment.
  • First-line Treatment: Cognitive Behavioral Therapy for Insomnia (CBT-I) is superior.
  • Pharmacotherapy: Short-term Z-drugs (Zolpidem) or short-acting BZDs; consider DORAs.
  • Sleep Hygiene: Key in CBT-I, but often insufficient alone.
  • Polysomnography (PSG): Not routine; for suspected comorbid sleep disorders.
  • Comorbidities: High with psychiatric (depression, anxiety) and medical conditions.
  • Risks: ↑ accidents, mood disorders, cardiovascular disease.

Practice Questions: Insomnia Disorder

Test your understanding with these related questions

A 56-year-old woman with diabetes, hypertension, and hyperlipidemia is found to have an A1C of 11 despite her best attempts at diet and faithfully taking her metformin and glyburide. She reports severe fatigue and sleepiness in the daytime, which has limited her ability to exercise. On examination, she is obese, has a full appearing posterior pharynx, clear lungs, a normal heart examination, and trace bilateral edema. Her TSH is 2.0 m/L (normal). Before adding another oral agent or switching to insulin, what is the best next step?

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Flashcards: Insomnia Disorder

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Somnambulism (sleepwalking) is seen in 4-8 year old children and usually _____ after adolescence

TAP TO REVEAL ANSWER

Somnambulism (sleepwalking) is seen in 4-8 year old children and usually _____ after adolescence

resolves::Resolves/Worsens

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