Translation guide
Describes the condition of being unable to sleep. Japanese has several terms, ranging from clinical to casual, and often uses descriptive phrases.
To refer to the condition of insomnia in a neutral or medical context.
To say you can't sleep in a casual conversation.
Literally 'can't sleep'. The most common and natural way to express insomnia in daily speech.
I couldn't sleep at all last night.
Lately, I've been having sleepless nights.
Specifically means 'unable to fall asleep'. Focuses on the initial difficulty of drifting off.
It's so hot I can't fall asleep.
Means 'lack of sleep' or 'sleep deprivation'. Often used to describe the state of being tired due to insufficient sleep, rather than the inability to sleep.
To describe particular patterns of sleeplessness.
Use 眠れない (can't sleep) for everyday situations. 不眠症 is a medical diagnosis and sounds more serious. If you just had a bad night, say 眠れなかった, not 不眠症だった.
Japanese often expresses the experience of insomnia with phrases like なかなか眠れない (just can't seem to sleep) or 夜中に目が覚める (wake up in the middle of the night).
Continuous sleeplessness is bad for your health.
寝不足で頭が痛い。
I have a headache from lack of sleep.
Early morning awakening is one of the symptoms of depression.