This is a really good, quick-to-read short story speculating on how humanity would deal with the challenge of keeping their minds occupied during a decades-long interstellar voyage. After a series of failures all ending with the crews going mad, the government assigns each crew member a daily dose of an extremely powerful, experimental hallucinogen. Unfortunately, the hallucinogen has effects no one could have anticipated.
This story is an early example of Spinrad's talent and an example of one of my favorite science-fiction authors. It is available for free on Project Gutenberg.