Hi Stryped.
It's possible you have a sleep disorder. does this ever happen if you've not been drinking or using drugs/medicines? If not, I would be inclined to believe its the alcohol. Many people get violent or do things they never would do while sober once under the influence.
If you can't quit drinking, you might want to get some help to do so. Stick around, read the stickies at the top of the forums. Lots of good advice and support here!
Love from Lenina