精神病是由于大腦功能紊亂而發生的感覺、記憶、思維、感情、行為等方面表現異常的病。

　　雙語例句：

　　醫生說她有一種精神病,她不能像正常人一樣照顧自己。

　　The doctor said she had a kind of mental disease, she couldn't look after herself like a normal person.

　　“精神病”這個詞很難下定義。

　　The term 'mental illness' is difficult to define.

　　精神病并不可羞愧。

　　Mental illness is nothing to be ashamed of.

　　許多人在人生的某個階段都會得精神病。

　　Many people suffer from mental illness at some point in their lives.

　　他有精神病，不能對自己的行為負責。

　　He is mentally ill and cannot be held responsible for his actions.