By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) – We have talked about this before…the link between brain chemicals and addiction.

Researchers have studied the relationship between alcohol consumption and variations in a gene involved in processing the brain chemical serotonin in people who had an alcohol dependency. They found that those with a particular variation in one gene involved in serotonin processing were more likely to drink more alcohol than those with a different variation. Researchers believe that the chronic alcoholics may drink, in part, to alleviate a deficit in serotonin. Those with particular variations may experience a greater or lesser degree of deficit.

Addiction – and alcoholism in general – are very complex issues but there is no doubt that there is more to the problem at the brain chemical level.