, 2008), although Enzalutamide cost these relationships are not well established among consumers of ST. Fifth, our study assessed only lifetime diagnoses of anxiety and depression, rather than dimensional symptom measures. Other studies have found significant associations between ST use and symptoms of negative affectivity, such as depression (Rouse, 1989) and anger (Kerby et al., 2003). Finally, these results cannot be generalized to all American Indians as considerable diversity exists in geography, culture, urbanization, and availability of tobacco cessation programs. The association between ST use and psychiatric disorders does not appear to be nearly as robust as the relationship between cigarette use with anxiety and depressive disorders. It is possible that ST does not carry the same reinforcement value (e.

g., tension reduction, enjoyment) that cigarette smoking may confer among those who struggle with anxiety and depression. Anxiety and depressive disorders are common among American Indian communities, and use of all tobacco products can be frequent. Shared biological, environmental, and behavioral mechanisms may underlie tobacco use, anxiety, and depression, and illuminating these mechanisms may help inform successful tobacco quit programs. It remains questionable as to whether the presence of an anxiety or depressive disorder among ST users has any bearing on the ability to successfully quit. Only a single study to date found that ST users with a history of depression were more likely those without depression to continue using 1 year after participating in a pharmacologic trial (Ebbert et al.

, 2008). Replication of these findings is clearly warranted. The public health impact of tobacco use remains a serious issue, especially in the American Indian community where rates of usage are disproportionately high (Steele, Cardinez, Richardson, Tom-Orme, & Shaw, 2008). Further efforts are needed to develop and disseminate effective cessation programs to these historically underserved tribal communities. Funding This work was supported by the National Institutes of Health/National Institute on Aging (P30 AG15297 to S.M.M.), Agency for Healthcare Research and Quality (P01 HS10854 to S.M.M.), the National Institutes of Health/National Center for Minority Health and Health Disparities (P60 MD000507 to S.M.M.), the National Institutes of Health/National Institute of Mental Health (P01 MH42473 and R01 MH48174 to S.

M.M.), and the National Cancer Institute (SR01 CA126620 to D.B.). Declaration of Interests C.N.S., P. R.- B., C.N. , A.B. , J.G. , S.M.M. , D.B. , and the members of the AI-SUPERPFP Team declare that they have no competing interests. Acknowledgments The AI-SUPERPFP team includes Janette Beals, Cecelia K. Big Crow, Buck Chambers, Michelle L. Christensen, Denise Dacomitinib A. Dillard, Karen DuBray, Paula A.