All addictive substances involve the pleasure/reward centers of the brain. The neurotransmitter dopamine seems to be involved in most addictive behaviors. Giving up everything all at once is probably not a good idea.
I actually found it easier to quit drinking for good, than I did smoking. Like SlimSlim above I started smoking at about the age of 12. Over the decades tho I quit smoking quite a few times, but always started again. I eventually switched from cigarettes to cigars but that's little consolation. Quit again on AUG. 1, (a few days ago), we'll see how that goes.