I Was a Teenage Werewolf (1957)

 Was a Teenage Werewolf is a 1957 horror film starring Michael Landon as a troubled teenager and Whit Bissell as the primary adult. It was co-written and produced by cult film producer Herman Cohen, and was one of the most successful films released by American International Pictures (AIP).

Landon's character is Tony Rivers, a disturbed, angry young man in the James Dean Rebel Without a Cause tradition, who seeks hypnotherapy for his problem. Unfortunately, the practitioner he seeks out, played by Bissell, is also a very disturbed man with definite mad scientist overtones who, with the help of scopolamine injections, successfully regresses his patient into a werewolf with tragic results. He is under the belief that man, instead of moving forward, must go back to their pre-evolution states (for some reason, a werewolf). Tony, meanwhile, knows nothing of this. Tony transforms in the high school gymnasium (after he is startled by the school bell suddenly ringing close to him) and kills a girl who is there practicing gymnastics. Realizing that something is wrong, Rivers goes back to the doctor for help. The doctor hypnotizes him again, making him turn back into a werewolf. As he and his assistant, Hugo, prepare to take pictures of this achievement, the telephone rings, which wakes up Rivers and causes him to kill both the doctor and Hugo. He is then shot by the police as he runs from the doctor's building.

Variety reported: "Another in the cycle of regression themes is a combo teenager and science-fiction yarn which should do okay in the exploitation market  Only thing new about this Herman Cohen production is a psychiatrist's use of a problem teenager  but it's handled well enough to meet the requirements of this type film.  good performances help overcome deficiencies. Final reels, where the lad turns into a hairy-headed monster with drooling fangs, are inclined to be played too heavily." Variety went on to say that Landon delivers "a first-class characterization as the high school boy constantly in trouble." The film was very profitable, as it was made on a very low budget but grossed as much as US $2,000,000, compared to its $82,000 budget. Released in July of 1957, it was followed four months later by I Was a Teenage Frankenstein as well as Blood of Dracula, and by the sequel How to Make a Monster in July of 1958.

From Wikipedia

I WAS A TEENAGE WEREWOLF
GENE FOWLER JR.  (1957)
AIP
76 MIN
USA