How to say "insomnia" in Japanese

• 不眠ふみんCommon
  no-adjectiveCovers sleeplessness and wakefulness as a state — simply not getting sleep, whether a single bad night or ongoing. It points to the state itself rather than to insomnia as a named disorder.
  過労かろうやら不眠ふみんやらで、彼かれはとうとう病気びょうきになってしまった。↗

  What with fatigue and lack of sleep, he has fallen ill at last.
• 不眠症ふみんしょうCommon
  nounInsomnia as a medical condition: a disorder of being unable to sleep. This is the word used when speaking of suffering from insomnia or being treated for it.
  彼女かのじょは不眠症ふみんしょうから解放かいほうされた。↗

  She was relieved from insomnia.

Both words can translate 'insomnia': use 不眠 for sleeplessness or wakefulness as a state, and 不眠症 when insomnia is meant as a medical condition or disorder that a person suffers from.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 不眠ふみんsleeplessness
• 不眠症ふみんしょうsleeplessness
• インソムニアinsomnia