Insomnia and Hypersomnolence
What you must know
Insomnia disorder requires difficulty initiating/maintaining sleep or early awakening with daytime consequences, ≥3 nights/week for ≥3 months despite adequate opportunity. First-line treatment is CBT-I (stimulus control, sleep restriction, cognitive restructuring, relaxation, sleep hygiene). Pharmacotherapy is adjunctive; avoid long-term benzodiazepines in older adults.
Hypersomnolence disorders include narcolepsy type 1 (cataplexy, low CSF hypocretin-1 ≤110 pg/mL), narcolepsy type 2 (no cataplexy, normal hypocretin), idiopathic hypersomnia, and Kleine-Levin syndrome. The MSLT requires ≥2 sleep-onset REM periods (SOREMPs) and mean sleep latency ≤8 minutes; a preceding nocturnal PSG with REM latency ≤15 minutes can substitute for one SOREMP.
Traps
- Diagnosing insomnia without daytime impairment.
- Using MSLT after inadequate sleep or without a preceding PSG-both invalidate results.
- Confusing cataplexy (emotion-triggered, bilateral, brief) with sleep paralysis or hypnagogic hallucinations.
- Missing that narcolepsy type 1 requires low hypocretin OR cataplexy plus MSLT findings.
Rule of thumb
"CBT-I first, always" for chronic insomnia. For MSLT: "≤8 min latency and ≥2 SOREMPs."
Worked example
A 19-year-old with emotion-triggered knee buckling, sleep paralysis, and daytime sleepiness has MSLT mean latency 4 minutes with 3 SOREMPs. Diagnosis: narcolepsy type 1. Treat with modafinil or pitolisant for sleepiness; sodium oxybate for cataplexy.