The effect of nicotine addiction on quitting smoking

What does nicotine addiction mean? Is it harder for nicotine addicts to quit smoking?

This study was funded with a grant from the Global Action to End Smoking, Inc. (“Global Action”), a US nonprofit 501(c)(3) private foundation.  Global Action had no role in the planning or execution of this survey/report/study, data analysis, or publication of results.  For more information about Global Action, please visit its website.