It may start out as fun on the weekends. Then the weekends spill into weekdays, and suddenly the party is happening way too often. It may even begin to affect your relationships, your work, and more.

If you are wondering if you have a problem with alcohol or are worried that a family member, friend or co-worker might be abusing alcohol, you have already taken an important first step.

Why do some people become addicted, while others do not? Studies of identical twins indicate that as much as half of an individual's risk of becoming addicted to alcohol, or other drugs depends on his or her genes. Pinning down the biological basis for this risk is an important avenue of research for scientists trying to solve the problem of drug abuse.

Genes – functional units that make up our DNA – provide the information that directs our bodies' basic cellular activities. Research on the human genome has shown that the DNA sequences of any two individuals are 99.9% identical. However, that 0.1% variation is profoundly important, contributing to visible differences, like height and hair color, and to invisible differences, such as increased risk for heart disease, stroke, diabetes…and addiction.