Normally we only dream during the twilight hours of sleep. If these are occurring throughout the night then you are not getting enough deep sleep. Chocolate is well known for causing nightmares see:
I suffer from stress and eat chocolate and cheese even before going to bed and I don't suffer from violent nightmares - most likely to be an old wives tale - but then again that maybe proves I'm not susceptible to it.
This might sound daft - but try and control your dreams - the best way to describe it is if you don't like the way your dream is going become conscious of it ( while you are still asleep) and turn it in to what you want it.
On the odd time I would get a " bad dream " this is what I do and it does work - for me.
well its not violent like that. its more liek getting murdered and stuff along that line, but i see everything in great detail.
and they all seem to be in the same setting.
when i was at schoool in the english department.
The Chinese seem to use MSG with everything. If I ate a late-night Chinese it would guarantee nightmares. I've given up on them, Indian curries instead !