I would strongly caution anyone using Chantix to be aware of the side effects and stop taking it if they become an issue.
My DH used it for several weeks. The dreams were bad if he took it in the evening. When he took it in the morning he would vomit at work-- not a great idea working in an operating room. It was effective for the smoking which is why he kept taking it.
He said he had no desire to smoke, but the real issue was that he had no desire to do
anything. This was a man who enjoyed working a full time job plus call, going to school full time, and doing large renovations on our home at the same time. When taking the Chantix he could come home from work, sit down on the couch, and not care if he didn't do anything else.
When he said he had "lost the will to live" he stopped taking it.
I know several other people who had the same effects (and worse) and had to stop taking it.