In addition to the enzyme genes, neurotransmitter genes have been associated with increased risk for alcohol dependence. Psychotropic substances (including alcohol) modify the neurophysiological chemical changes that take place in the brain. The indications for a genetically defined predisposition responsible for alcohol dependence are examined in the field of different candidates for neurotransmitter genes [21,22]. These genes influence the vulnerability of developing dependency syndromes, such as alcoholism. One of the genes studied is the D2 dopamine receptor protein (genetic locus DRD2). Dopamine is generally known to play a significant role in the substance dependence development, and one of its receptors is the DRD2 receptor. Alcohol acts in the mesolimbic striatum, altering the synaptic function thus causing increased dopaminergic activity [22,23].
