32 yo male, brain problems possible.

I'm a 32 y/o male 6'5" 260 lbs. I have used mj a few times, I think I'm allergic but that's beside the point, I huffed air duster for a few months and now avoid it for control issues. I'm a regular tobacco user, and semi-regular alcohol user. I have also had several serious concussions in my life. When I am drunk/ high/ buzzed on tobacco, or any combination thereof, my brain feels too small for my skull. I mean when I'm not under the influence of anything I can feel it moving around with vigorous movement but when I am under the influence it takes much less to notice. Should I have this checked or is it normal? Could it be genetics? I have also been diagnosed with ADHD and mild schizophrenia if that makes a difference. Sorry for the wall and if I broke any rules.

Edit: I have also been diagnosed with clinical PTSD from military service, if that makes a difference.