I don’t know for sure if this is a slang expression or not. Since I cannot find it in my dictionary (The Random House Collega Dictionary; 1975), I just put it here.

Etymology

This phrase was originally used in the first World War to refer to quadruple amputees, who apparently could not walk by themselves so that they had to be transported around in baskets.

Unlike the above cartoon, this etymology sounds like a grisly legend, but it actually happened that way.

Some say, the term connotes mental illness. Someone who is a “basket case” is usually not just hopeless but hopelessly crazy or traumatized. He remains psychologically beyond remedy.

However, as far as I checked around, others use this term casually—rather sarcastically without rolling their eyes as shown in the following example:

Ever since he lost his job, Jimmy has been living like a basket case.

In the above case, Jimmy lives like a bum, not a hopelessly crazy or traumatized man. Maybe, he is. Who knows?

Noun phrase

1. a demented man, a psycho, a crazy man, a person who is hopelessly broken down
2. a weak man, a weakling
3. a disadvantaged person, a disabled person
4. a bum

Synonyms

• psycho
• psychotic person
• mad person
• deranged person
• disturbed person
• gutless person
• weakling
• vagrant
• vagabond
• loon

Usage

Tony has been an emotional basket case since he lost his job.

Mary turned into a basket case when she lost her sweetheart.

Africa was once the basket case of the planet.

USSR was an economic basket case before it disintegrated.

Since Jimmy failed the entrance exam to the university, he’s been a basket case.

After his wife left him, Norman became a real basket case.

That firm was such a basket case that the owners had to shut it down.