mentally ill person; person with a mental disorder
Clinical or formal term; can sound blunt or stigmatizing in casual contexts. In modern sensitive usage, 精神障害者 is often preferred.
Mentally ill persons have the right to receive appropriate treatment.
He was hospitalized as a mentally ill person.
精神異常者 is a clinical, formal term for someone with a mental disorder, while 狂人 is a plainer literary word for a madman.
Compound of 精神 (mind, spirit), 異常 (abnormality), and 者 (person).