Final answer:
Ken Kesey, the former ward attendant at a mental hospital, is the author of 'One Flew Over the Cuckoo's Nest', a novel inspired by his experiences and the use of psychoactive drugs in the hospital where he worked.
Step-by-step explanation:
The former ward attendant in a mental hospital who wrote One Flew Over the Cuckoo's Nest was Ken Kesey. Prior to writing his famous novel, Kesey worked at the Veterans Administration Hospital in Menlo Park, California, where his experiences with patients and the use of psychoactive drugs as treatment formed the basis for the characters and settings in his book. This novel, with its critical view on the institutional process and the human mind, remains a significant piece of mid-20th-century American literature and has also been adapted into a successful stage play and an Academy Award-winning film.