The selected GABAergic genes were strong candidates for involvement in addiction and in addictive tendencies. Indeed, 14/25 of the human genes and 12/25 of the rat genes showed nominally significant differences in gene expression. The global p value, calculated using the truncated product method [29] for overall differences in expression of the 25 genes in humans with alcohol or cocaine addiction compared with controls was p = 9.1×10−14. The global p value for overall differences in expression of the 25 genes in P rats compared with NP rats was p = 7.0×10−11.
