Candidate gene based investigations into the biology of alcohol-related disease have focused in a few key areas. The most common focus is well-established neurotransmitter systems commonly studied in psychiatric disorders such as dopamine, serotonin, and glutamate, their receptors, transporters, and enzymes of degradation. The second most common area of investigation is that of more specialized neurotransmitters such as vasopressin, and orexin. A third common theme is genes related to one carbon metabolism. Fourth and fifth common areas of investigation are genes related to craving addiction, particularly with respect to the endogenous opioid system, or those related to neuronal growth and homeostasis.
