Can't turn 360 degrees

I cannot turn around all the way using my mouse. 

What I expected to happen was...:
I would turn around fully at will

What actually happened was...:
When I turn either direction, at a certain point it acts like I hit a wall and I can no longer turn in that direction.

Steps to Reproduce:
1. Stand still
2. Turn your character around using the mouse
3. Try it the other way as well