. >> reporter: for "nightline," i'm aditi roy in port townsend, >> our thanks to aditi for that adventure. we'll be right back. i'm billy, and i quit smoking with chantix. i don't know that i can put into words how happy i was when i quit. it's like losing some baggage, i don't have to carry it around with me anymore. chantix made it possible for me to quit smoking. along with support, chantix (varenicline) is proven to help people quit smoking. chantix definitely helped reduce my urge to smoke. some people had changes in behavior, thinking or mood, hostility, agitation, depressed mood and suicidal thoughts or actions while taking or after stopping chantix. some had seizures while taking chantix. if you have any of these, stop chantix and call your doctor right away. tell your doctor about any history of mental health problems, which could get worse or of seizures. don't take chantix if you've had a serious allergic or skin reaction to it. if you have these, stop chantix and call your doctor right away as some can be life-threatening. tell your doctor if you have heart or blood vessel pro