Generally speaking, there are two approaches available to address this problem of identifying susceptibility loci for nicotine dependence and other complex disorders. The first approach is to repeat and extend these genome-wide linkage analyses in different populations; the second is to use higher marker densities for association genome scanning studies. Based on the availability of information on smoking phenotype in the Framingham Heart Study population, we adopted the first genome-wide scan approach to identify susceptibility loci for nicotine dependence in the present study.
