Despite extensive knowledge and education about the harmful effects of ultraviolet (UV) light, the incidence of melanoma and non-melanoma skin cancers is continuing to increase. For behavioral interventions to be effective, it is critical to understand the factors that underlie behaviors. Recent research suggests there may be physiological effects of UV exposure (e.g. release of endorphins) that motivate tanning behaviors, and that tanning addiction may be a physiological phenomenon, with possible genetic modifiers as has been shown for other addictive behaviors. As we are collecting extensive data on tanning behaviors and attitudes towards tanning within our large case-control study on early onset (aged under 40) basal cell carcinoma (BCC), and have DNA samples, we have a unique opportunity to cost-effectively evaluate this newer hypothesis. We propose to assess tanning dependence (defined by analogy with generally-recognized forms of substance dependence) and the relationship between tanning dependence and addiction risk genes within the setting of our BCC case-control study. More specifically, we propose to administer an additional survey to assess tanning dependence (addiction) to participants of our study of early onset skin cancer, which will allow us to address the following aims: (1) To assess the prevalence of tanning dependence in cases and controls, by sex; (2) To assess the association between tanning dependence (addiction) and actual tanning behaviors (e.g., indoor and outdoor tanning); that is, how much of tanning behavior in young people is explained by addiction?; (3) To assess the role of candidate genes that are thought to be related to multiple types of addiction (members of the opioid pathway, and circadian rhythm genes) in tanning addiction. These data will synergize with our case-control study data to provide a comprehensive picture of tanning motivation and behavior in relation to skin cancer risk. If we find involvement of genes in tanning addiction that are related to other types of addiction, this would warrant new approaches to reduce harmful exposures in dependent persons as has been done with other harmful addictive disorders. PUBLIC HEALTH RELEVANCE: The proposed study will investigate the epidemiology and genetics of tanning dependence (addiction) which will help us better understand motivation for tanning and open new avenues for development of innovative interventions to reduce ultraviolet light exposure and ultimately reduce melanoma and nonmelanoma skin cancers. Developing more effective interventions is essential as skin cancer is the most common cancer in the United States and the incidence of both melanoma and nonmelanoma skin cancer continues to increase.