CHRNA3 and nicotine dependence: Another candidate gene association study investigating 348 of 359 candidate genes included in this study [50] evaluated association with a dichotomized nicotine dependence phenotype, and identified nicotinic receptor SNPs associated with FTND, including rs578776 and rs1051730 within CHRNA3, and rs16969968 within CHRNA5. Nicotinic receptors are also associated with CPD in the candidate gene group analysis as the most significantly associated gene group, and also with the phenotype SMKDU (Table 4).