The emerging research on biomarkers in alcohol dependence has lead to a deeper understanding of the neurobiological mechanisms in alcoholism. The molecular networks and the pathophysiological circuits are complex and not completely unrevealed up to now. One of the most interesting biomarkers described to play an important role in alcohol dependence is the amino-acid homocysteine, which has particularly been linked with brain atrophy and withdrawal seizures. However, the molecular networks of homocysteine are complex and include an important impact on epigenetic regulation via homocysteine's action as a methyl-group donator in human metabolism. So, alterations in human homocysteine levels can influence DNA-methylation of specific gene areas which may change expression and synthesis of proteins possibly important for the genesis and maintenance of alcohol dependence.