Extreme agression

Question
We have a 1 and a half year old female cat who is very aggressive for what seems like no reason at all. I have researched how to help her many many times and implemented things like trying to keep her more busy/amused. Catching her before the behavior starts and making unpleasant noises/distracting her. Ignoring her all together when she gets in a bad mood, ect. But she still attacks sometimes without any warning at all.
It seems like she has always attacked myself or other females and never to the same degree my husband.
Here are some scenarios where she has forcefully attacked me. She will be sitting/sleeping on the couch and I have sat down semi close to her and she gets upset and will bite me as hard as she can, leaving punctures and grip with her claws so I cannot pull away.
She doesn't usually really like to be touched but sometimes will jump up on my lap and purr and rub against me but the minute i touch her will freak out.
I'm getting to my last straw, this morning around 4am she jumped up into the bed, all seemingly happy and curled up right beside me, I reached over to scratch her ears (the one thing she does usually like) and she attacked to to the worst degree ever. I have 14 claw marks and two large punctures from her teeth. And there was absolutely no warning. No swinging of the tail, no hiss, nothing to tell me she wasn't enjoying it.
I am at my last straw, I am wondering what to do with a cat who acts this way, is there anyone who can help her. because at this point I cant handle her anymore, I am going to have scars all up my arm, I honestly look like my arm went through a window.
Please let me know what you think, is this something we have caused in her?

Answer
Amanda,

This does seem rather extreme.  Have you had her thyroid levels checked?  Sometimes this is the problem. I am assuming she is spayed, if not, this could also cause some of the behaviors. I would work with my vet to see if there is a medical problem.  It does also sound as if she was never socialized to humans.

See what your vet says, and then we can go from there.

Concerned regards... Norm.