The CYP2A6 gene is located on the long arm of chromosome 19 [31]. CYP2A6 belongs to the family of genes known as cytochrome P450, which has a mixed-function oxidase system and is involved in the metabolism of xenobiotics in the body. CYP2A6 variants have properties that induce or inhibit nicotine according to their structural function [32]; thus, they are hypothesized to enhance or alter nicotine dependence treatment [3]. This evidence concerns the gene CYP2A6 and nicotine dependence.