the beta frequency of the EEG also is associated with a diagnosis of alcohol dependence, based on criteria from the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM–IV) (Edenberg et al. 2004). This suggests that variations in the GABAA receptor 2–subunit gene (GABRA2) (the gene encoding the alpha 2 subunit of the GABAA receptor) affect the level of neural excitability, which in turn affects the predisposition to develop alcohol dependence.
