How to say "amnesia" in Japanese

• 健忘症けんぼうしょう
  nounThe clinical name for amnesia as a medical condition; use it when naming the disorder itself, as in a diagnosis or medical explanation, rather than for describing someone simply losing their memories.
• 記憶喪失症きおくそうしつしょう
  nounNames amnesia as an explicit disorder, but it is seldom the word you want for this sense: 健忘症 is the term for the condition, and 記憶喪失 covers the state of memory loss.
• 記憶喪失きおくそうしつ
  no-adjectiveCovers 'loss of memory' directly: the state of having lost one's memory, as after an accident or in fiction. It describes the phenomenon rather than naming a diagnosis.
  彼かれは記憶きおく喪失そうしつで悩なやんでいる。↗

  He is suffering from loss of memory.
• 健忘けんぼう
  nounGlossed simply 'amnesia', but seldom the word you want on its own: it is really the base of 健忘症, so use that fuller term when naming the condition.

For amnesia as a named condition use 健忘症; for the state of losing one's memory use 記憶喪失; 記憶喪失症 and the bare form 健忘 are uncommon variants you will seldom need.

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

• 健忘症けんぼうしょうamnesia
• 記憶喪失症きおくそうしつしょうamnesia
• 記憶喪失きおくそうしつloss of memory
• 健忘けんぼうamnesia