Project Summary/Abstract Areca nut, also known as betel nut, is the fourth most commonly consumed psychoactive substance in the world, following only alcohol, nicotine, and caffeine in prevalence of consumption. Although betel nut is chewed by approximately 600 million people globally, its use is concentrated in South Asia, Southeast Asia, and some Pacific islands. Betel nut has been classified as a Group 1 carcinogen by the International Agency for Research on Cancer. Betel nut chewing has been associated with oral and oropharyngeal cancer, oral lesions, oral leukoplakia, submucous fibrosis, gum disease, and cancer of the pharynx and esophagus. Despite the global significance and carcinogenicity of betel nut, there has been very little behavioral or psychological research about betel nut chewing, and there has been no systematic research on the topic of betel nut cessation interventions. The proposed research builds directly upon our prior research. Our survey data suggest that betel nut chewers, like smokers, generally want and intend to quit, but do not have specific plans of how or when they will quit. In addition, most betel nut chewers in our sample already have tried to quit on one or more occasions. These findings suggest that betel nut chewers could benefit from cessation programs modeled after smoking cessation programs. During 2014, we conducted a feasibility study of our betel nut cessation program. The program was well received and yielded surprisingly high rates of self- reported betel nut cessation. Our primary aim is to test the efficacy of an intensive group-based betel nut cessation program. Betel nut cessation will be bio-verified by employing biomarkers developed in our previous research. Participants (n=324) will be betel nut chewers from Guam and Saipan who are willing to attempt to quit chewing. Participants will be randomly assigned either to an intensive intervention condition or to a minimal intervention control condition. Participants in the intervention condition will receive a group-based cessation program consisting of five hour-long sessions over the span of 22 days, as well as a brochure with advice about quitting betel nut. Participants in the control condition will receive a brochure with advice about quitting betel nut. The proposed intervention trial will allow us to assess the 1-month and 6-month efficacy of the intervention compared to a minimal control intervention. We hypothesize that the intensive betel nut cessation intervention will produce a significantly greater cessation rate compared to the minimal control condition at the 6-month follow-up assessment.