I've done a post before about whether zombies were feasible, but are werewolves?
Physically, the closest thing we have is hypertrichosis. This is a condition of overgrowth of hair on the body (above). This is an inherited condition. In the past, people with this condition were relegated to being circus attractions, as they were often outcast from their communities. With knowledge and technology now, it's possible to perform laser hair removal, but there is a good deal of regrowth. This is a very resistant disease. Although a person might look like a wolfman, there are no personality traits associated with it. It's simply a person who produces a lot of hair.
There is a condition called lycanthropy where one believes himself capable of turning into a wolf.(Here's an interesting and entertaining man showing Josh Gates of "Destination Truth" how he turns into the local wolf/man).
Disclose.tv - Destination Truth Lobizon Transformation Video
There are many variations of this condition including a true mental illness, the belief in magic as trans-formative, the believe in curses and "infection."
So, what is more scary? The concept of someone actually become a wolf or someone believing he is one and acting out?
Some good werewolf movies to consider:
The Wolf Man
An American Werewolf in London
What's up on Netflix Instant Watch in the genre right now?
Werewolf Hunter: Murders in the woods and a soap salesman takes the blame, but says he's a werewolf.
Werewolf of London: Beautifully crafted and terribly atmospheric old classic about a man studying a nightblooming flower who is bitten.
Wolf Moon: Drifter in town that a woman falls for and finds out he has a family curse.
An American Werewolf in London: Classic, best transformation, chilling and witty.