It is an interesting finding that 3 SNPs in the intron 6 region of GRM8 were significantly associated with not only the theta band of EROs but also the ICD-10 diagnosis of alcohol dependence. There is a trend that these 3 SNPs may also be associated with the DSM-IV diagnostic criteria of alcohol dependence (p=0.058, 0.070, 0.073 with rs1361995, rs10487457, rs10487459 respectively) although it did not reach a statistically significant level (p<0.05) in the dataset we examined. The ICD-10 criteria for alcohol dependence suggest more biological and somewhat more restrictive set compared to those for DSM-IV, since the former are focused on a cluster of the consequences after repeated use of alcohol. For example, the ICD-10 criteria require “a cluster of behavioral, cognitive, and physiological phenomena that develop after repeated alcohol use and that typically include a strong desire to take the substance, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to drug use than to other activities and obligations, increased tolerance, and sometimes a physical withdrawal state”, while the DSM-IV requires only three or more of similar criteria to make such diagnosis.
