Hey,
This is a good question. I have wondered this before and not remembered to post. I would also like to know. I know that when i would go drink with friends and we woke up with a hangover we would be like "not doing that again" Then someone would call and the BBQ was on again! But I wonder if its the same thing with drugs. I have thought before and told my sister. When a person drinks and is hungover, they know what they have done. But I think with my AH (meth) he just maintains so I really don't think he ever comes down long enough to realize. So he crashes eventually and when he can finally drag himself out of bed he just gets high and stays that way. I don't know for sure though. That's just my opinion. I have never had personal experience with drugs. Just to much beer....
Didn't mean to high jack your post but, you must have read my mind!