Tobacco Addiction, also known as nicotine dependence, is related to major depressive disorder and depressive disorder. An important gene associated with Tobacco Addiction is SLC6A3 (Solute Carrier Family 6 Member 3), and among its related pathways/superpathways are Metabolism and Metapathway biotransformation Phase I and II. The drugs Ethanol and Naltrexone have been mentioned in the context of this disorder. Affiliated tissues include lung and brain, and related phenotypes are homeostasis/metabolism and nervous system