A friend of mine took Chantix over a year ago, they quit smoking, once off Chantix they started again, they ended up quiting again just by chewing gum. My question is, how long should the side effects last? It has been over and year and they are super sensitive about stuff and can get very angry for no reason. They don't talk about wanting to kill themselfs, just mainly agree about everything and thinking that everyone is againist them. Should they be getting on some pills?