It makes reference in the form of a parabola to someone who has lost his mental health and has no cure.
It is said that people without cure to a mental disease used to be sent to a mental health care facility for life where they would manufacture baskets for the rest of their lives.
Peter smokes two packs a day, he is such a basket case
A basketcase is common word used to describe a social outcast in school. Some characteristics of a basketcase included emotional instability, weirdness, and constant isolation from mainstream society. A basketcase is often independent and isolationist, in other words, anti-social.
This word was widely used in the 80s. Like most slang prior to the 90s, it has fallen into disuse. Today, a basketcase can be categorized in three groups known as the goth, emo, and punk.
"I know, I don't follow the trend, you got a problem with that?" - Basketcase
2) A Green Day song sung by the one and only Billie Joe Armstrong. Arguably one of the great Green Day songs, if not one of the great songs of the 90's.
2) Be quiet, I am listening to Basket Case.
Modern day usage is to describe someone that is in need of extreme assistance(mental or physical).