تعریف و معنای "[go] off the deep end"

What is the origin of the idiom "go off the deep end" and when to use it?

The exact origin of the idiom "go off the deep end" is uncertain, but it is believed to have originated in the early 20th century, possibly in the United States. This expression is often used to describe emotional breakdowns, sudden outbursts, or drastic decisions made without careful consideration. It can be applied to situations where individuals respond intensely to stress, frustration, or personal challenges, often crossing social or behavioral boundaries.