To substance abuse? Withdrawal symptoms, addiction issues, my mental health has certainly taken a beating and I feel like my brain just gave up at some point and I'm no longer really even able to function in society. I can't focus on anything, I can't remember things even remotely as well as I should and I would say I used to have great memory, I go on multi-day binges of being awake on too high doses of stimulants (overamp nearly every time) and don't eat, drink water or take care of myself for days then crash and "recover" from the lack of self care only to either do it again or if I ran out I'll just start drinking heavily while taking benzos and whatever other chemicals that I might have to just have a moment of not being sober so I don't have to face my problems and can feel ok. Hope this makes any sense lol..
I also do hit myself sometimes when I just feel like It.
Tolerance is a bitch and the cause of much of any substance abuser's misery.