Altered States

Altered States is a 1980 American science fiction-horror film adaptation of a novel by the same name by playwright and screenwriter Paddy Chayefsky. Altered States was Chayefsky's only novel and his final screenplay. Both the novel and the film are based on John C. Lilly's sensory deprivation research conducted in isolation tanks under the influence of psychoactive drugs like mescaline, ketamine and LSD.