By Dr. Brian McDonough, Medical Editor

PHILADELPHIA (CBS) - There is no doubt that people prone to excess gambling, drinking or drug use can switch from one vice to another. Those who do this are said to have addictive personalities.

Addictions are not always associated with activities which have a stigma. People can have addiction to coffee, food or even work. But a growing amount of work is being focused on people who fit the profile of multiple addictions.

The work is in its infancy, but it seems to focus on the role of amino acids in the brain. And clearly, if there’s a way we can attack addictions, try to understand them and deal with them, so much the better.

There is no doubt there is much to learn.