The film was originally called Speed is of the Essence[1]: 73  and reunited the studio, director, producers and writer of The Strawberry Statement.

Irwin Winkler wrote in his memoirs that MGM's then head of production James Aubrey was the one who cast Michael Sarrazin and Jacqueline Bisset, although the director and producer liked both actors.

Winkler says Aubrey demanded reshoots be done by another director and the producers hired John Alviden to do another three weeks of filming; they would later work together on Rocky.

[1]: 814–851/3917 The magazine New York's Judith Crist disliked Hagmann's direction and Horovitz's screenwriting and wrote, "[It] is a sloppy story about an intern driven to drugs because he sees kids and old people get sick, and who apparently makes his girl an addict too—or simply makes her stop wearing eyeliner.

[2] Roger Greenspun of The New York Times wrote that Believe in Me avoided melodrama seen in other drug films but found that it had predictable surprises and failed to explain "crucial" questions.