what you can expect from a psychiatric hospital is that they will heavily medicate you to keep you from killing yourself and then theyll adjust the meds until you are somewhat functional and then theyll let you go home.
If you are crafty youll find a way to sneak cigarettes in the bathroom with other smokers who have organized a plan to do this. you wont like being under other peoples control. but if it keeps you alive until you get better then the hospital is a good idea and a necessary evil.
do it and live. bite the bullet.
g'luck
-pi