白天精神病晚上抑郁症
[bái tiān jīng shén bìng wăn shàng yì yù zhèng]
'Mental illness by day, depression by night.' A humorous or exaggerated expression implying fluctuations in mental health or energy levels. Could also suggest someone feels like they're overly excitable or hyper during the day and then depressed at night, highlighting extreme changes in moods.