noun
Medical or literary term for a depressive state; in everyday conversation うつ病 or うつ is more common.
彼は長い間気鬱症に悩まされている。
He has been suffering from depression for a long time.
うつ病 is the standard modern medical term for clinical depression, while 気鬱症 is a more literary or older term for a melancholic state.
Compound of 気 (spirit, mood), 鬱 (gloom, depression), and 症 (symptom, condition). The exact historical derivation is uncertain, but the term follows a common pattern for naming medical conditions.