What is the origin of the idiom "basket case" and when to use it?

The idiom "basket case" has its origins in the aftermath of World War I, particularly during World War II. It was originally a term used in medical contexts to describe soldiers who had lost all four limbs and required a basket or crate to carry them. Over time, the term evolved to refer to someone who is mentally or emotionally unstable and unable to cope with the stresses of life.