Narcolepsy

Disease Description (Causes and Symptoms)

• Definition: Narcolepsy is a chronic sleep disorder characterized by excessive daytime sleepiness (sleep attacks) during the day, REM sleep-related symptoms (hypnagogic hallucinations, sleep paralysis), and cataplexy triggered by emotional stimuli.
• Causes·pathophysiology: Hypocretin deficiency caused by the loss of hypocretin (orexin)-producing neurons in the lateral hypothalamus is considered the primary pathophysiological mechanism. Autoimmune, genetic (associated with HLA‑DQB1*06:02), and environmental factors are involved in combination.
• Main symptoms: Excessive daytime sleepiness (recovery after a short sleep), cataplexy (loss of muscle tone in response to emotional stimuli), hypnagogic hallucinations (vivid hallucinations resembling dreams), sleep paralysis (temporary paralysis when falling asleep or awakening), and fragmented nighttime sleep. Symptoms often begin during adolescence or early adulthood.

Treatment Methods

• Pharmacological treatment (standard and recently recommended)
  • Improving daytime sleepiness: Wake-promoting agents/histamine agents such as modafinil, armodafinil, and pitolisant. Methylphenidate and amphetamine-based stimulants are used as alternatives or adjuncts.
  • Cataplexy: Sodium oxybate (effective, regulated substance), antidepressants (tricyclic or SSRI/SNRI classes — REM-suppressing effects), etc.
  • Control of combined symptoms: Combination drug therapy when necessary (e.g., daytime medication + nighttime sodium oxybate).
• Nonpharmacological treatment
  • Regular nighttime sleep (ensuring sufficient sleep time) and regular planned daytime naps (e.g., 15–20 minutes).
  • Sleep hygiene education and safety measures when driving or operating machinery (risk is present when excessive sleepiness occurs before or during treatment).
• Procedures/surgery: Not applicable (mainly medication and behavioral therapy).
• Precautions (points of caution·risk of complications)
  • Wake-promoting agents and stimulants carry risks of insomnia, headache, decreased appetite, and cardiovascular side effects (increased heart rate and blood pressure) — caution is needed in people with a history of cardiovascular disease.
  • Sodium oxybate carries risks of sedation and respiratory depression, and has potential for abuse and misuse; caution is needed with prescribing and taking it.
  • The risk of suicidal ideation with antidepressants, especially in young people, requires monitoring.
  • If left untreated, the risk of accidents while driving or working increases, and depression and impaired occupational or academic functioning may occur.
• Prognosis
  • Because the condition is chronic, a complete cure is difficult. Appropriate medication and lifestyle management can control symptoms and improve quality of life.

Checklist Before an Outpatient Visit (Including Example Questions)

• Items to prepare
  • List of medications and supplements currently being taken (including doses and times of administration)
  • Past medical history and family history (including cardiovascular and psychiatric conditions)
  • Sleep diary (recommended for at least one week): sleep onset and end times, frequency and duration of naps, and situations in which sleepiness occurs
  • Previous test results (copies of polysomnography (PSG) and multiple sleep latency test (MSLT) results, if available)
  • Epworth Sleepiness Scale (ESS) score (if available)
  • Records of the effects of symptoms on daily life, such as accidents, falls, or driving problems
• Items that may be checked during the outpatient visit (to prepare for what the doctor may ask)
  • Frequency and duration of sleepiness, cataplexy (situations in which it occurs and frequency), and the presence of hallucinations or sleep paralysis
  • Quality of nighttime sleep (awakenings during the night, insomnia, or excessive sleep)
  • Medication history (effects and side effects)
• Example questions (questions for the patient to ask the doctor)
  • "What are the side effects of this medication?"
  • "What sleep tests should I have, and when should I have them?"
  • "What restrictions are needed regarding driving or work duties?"
  • "What will happen to my symptoms if I stop treatment?"

Examples of General Questions to Ask the Doctor

• What are the expected effects and side effects of this medication (e.g., modafinil or sodium oxybate)?
• What level of prognosis can be expected with treatment (such as recovery of the ability to perform daily activities or drive)?
• What lifestyle measures must I follow (such as sleep duration and nap schedules)?
• What are the recommendations regarding medication use during pregnancy or breastfeeding?

Examples of Condition-Specific Questions

• How should the mean sleep latency and number of REM-onset periods in my MSLT results be interpreted? (Based on polysomnography/MSLT results)
• Is a CSF hypocretin-1 test (or HLA test) necessary, and would the treatment or diagnostic classification (type 1 vs. type 2 narcolepsy) change depending on the test results?
• Could you explain whether sodium oxybate can be prescribed (indications, safety, and prescribing procedures)?

(Note: The standard for diagnosis is daytime MSLT after nighttime polysomnography (PSG), and a low CSF hypocretin-1 level (generally <110 pg/mL) is a confirmatory finding for type 1 narcolepsy (with cataplexy).)