Chantix immediately eliminated the effects of nicotine on my brain. I smoked like crazy for the first couple of days, trying to get SOMETHING out of a cigarette, quit completely on day 8 and once I got past the crankiness and depression, the only side effects I'm having are gas and constipation. So I take milk of magnesia on a regular basis now (LOL), but I haven't had a cigarette in two weeks.
I never had any weird dreams, but the week of depression was tough. I really want to quit, so I'm willing to put up with the withdrawals. I just needed something that made me not want another cigarette. Chantix is it for me.
As an aside, I tried Zyban about two years ago and ended up with hives from the top of my head to my knees, coming in waves (Zyban is time released) and lasting an entire week. Different medications affect people in different ways.
I believe that all of the side effects I have had are the same as the side effects I would have if I had quit cold turkey after 32 years of smoking. Chantix just took away the desire to smoke and made cigarettes taste really awful!