Although the studies reviewed in detail here have focused on the association between the GABA system and alcohol and nicotine dependence, other genes associated with these disorders also have been identified. These candidate genes fall into two broad classes: one group of genes has been identified in studies of nicotine or alcohol dependence but plays important roles throughout the central nervous system and is therefore likely associated with other addictions or psychiatric disorders as well. The second group of genes is specifically related to the actions of alcohol or nicotine and therefore may be specific to a given disorder.
