Translation guide
Somnambulism, or sleepwalking, is a sleep disorder where a person walks or performs other complex behaviors while still asleep. This guide covers how to express this concept naturally in Japanese, from clinical terms to everyday descriptions.
To refer to the medical condition of sleepwalking in formal or technical contexts.
The formal medical term for somnambulism. Used in clinical settings, medical documents, and by healthcare professionals.
彼は睡眠時遊行症と診断された。
He was diagnosed with somnambulism.
A slightly older or less technical term for sleepwalking, still understood in medical contexts but less common than 睡眠時遊行症.
夢遊症の患者は睡眠中に歩き回ることがある。
Patients with somnambulism may walk around during sleep.
To describe sleepwalking in casual conversation or non-specialist writing.
The most common lay term for sleepwalking. It literally means 'dream-walking disease' and is widely understood.
子供の頃、夢遊病があった。
I used to sleepwalk as a child.
夢遊病の人は起こさないほうがいいと言われている。
They say you shouldn't wake a sleepwalker.
A descriptive phrase meaning 'to walk while half-asleep/dazed'. It can refer to sleepwalking or just stumbling around groggily.
昨夜、寝ぼけて歩いて階段から落ちそうになった。
Last night I was sleepwalking and almost fell down the stairs.
A more explicit way to say 'to walk around due to sleepwalking'. It combines the noun with a verb phrase.
彼は夢遊病で歩き回っているところを見つかった。
He was found wandering around while sleepwalking.
To express the action of sleepwalking.
The most straightforward way to say 'to sleepwalk' as a verb phrase. It literally means 'to walk due to sleepwalking disease'.
彼はよく夢遊病で歩く。
He often sleepwalks.
A casual verb phrase for sleepwalking, though it can also mean just walking while drowsy.
子供が寝ぼけて歩いて台所に来た。
My child sleepwalked into the kitchen.
A rare, literary verb meaning 'to walk in one's sleep'. Not commonly used in modern conversation.
彼は夢中遊行する癖がある。
He has a habit of sleepwalking.
To refer to a sleepwalker.
The standard term for a person who suffers from sleepwalking.
夢遊病者は危険な行動をとることがある。
Sleepwalkers may engage in dangerous behavior.
A descriptive phrase meaning 'a person who walks while half-asleep'. More casual than 夢遊病者.
うちの弟は寝ぼけて歩く人だから、夜中に注意してる。
My younger brother is a sleepwalker, so I'm careful at night.
夢遊病 is the lay term for sleepwalking, while 睡眠時遊行症 is the formal medical diagnosis. In everyday conversation, 夢遊病 is perfectly acceptable and widely understood. Use 睡眠時遊行症 in clinical or academic writing.
医者は彼に睡眠時遊行症の診断を下した。
The doctor diagnosed him with somnambulism.
子供の夢遊病は成長とともに治ることが多い。
Childhood sleepwalking often resolves with age.
Somnambulism specifically involves walking or complex behaviors. Do not use 夢遊病 for nightmares (悪夢) or sleep talking (寝言).
悪夢を見て叫んだが、歩き回ってはいなかった。
I had a nightmare and screamed, but I wasn't walking around.
夢遊病は大人より子供に多い。
Somnambulism is more common in children than adults.
睡眠検査の結果、彼は睡眠時遊行症と診断された。
He was diagnosed with somnambulism after a sleep study.