I Was A Teenage Werewolf (1957)

Starring Michael Landon, Yvonne Lime, Whit Bissell, Tony Marshall, Dawn Richard
Directed by Gene Fowler, Jr.
(actor & director credits courtesy IMDB.com)

A teenager with a volatile temper reluctantly goes to a psychiatrist for help, not realizing the doctor has plans to regress him into a savage beast.

Better known today as an early starring vehicle for Michael Landon, before his many hit series on television, this was the first in a series of horror films with teenage monsters by producer Herman Cohen, which Wikipedia indicates were very successful.  Each of those films featured young people used as the subject of horrible experiments by twisted adults, and were built on themes of conflict between teenagers and grownups similar to those that permeated films like The Blob and Invasion Of The Saucer Men.  As for this movie, Landon's violent tantrums are a bit over the top, but it's an entertaining feature with a very good creature makeup, dominated by Landon's fearsome fangs.  Bissell is good as the villainous scientist, and would virtually repeat the same role in Cohen's I Was A Teenage Frankenstein.  I also enjoyed the casting of Vladimir Sokoloff as a janitor (from the Carpathian mountains!) who warns werewolves are real in his colorful accent.