Altered states int'l 1sh '80 William Hurt, Paddy Chayefsky, Ken Russell, sci-fi horror

Altered States, the classic 1980  bizarre science fiction (sci-fi) fantasy thriller ("In the basement of a university medical school Dr. Jessup floats naked in total darkness. The most terrifying experiment in the history of science is out of control... And the subject is himself."; about a guy who takes powerhouse drugs and mutates into early man)