These genes are clustered on chromosomes 4, 5 and 15. From Table 2 and Figure 2A it can be seen that alcoholics showed down-regulation of GABRA2 (p = 0.028) with a similar trend (p = 0.056) for the closely adjacent GABRG1. GABRG2 was down-regulated in both alcoholics and cocaine addicts compared with controls (p = 0.021) (Figures 2A, S2). GABRB1 was more highly expressed in cocaine addicts than in alcoholics (p = 0.044).
