They have discovered that alcoholism isn't just a human weakness it can be induced in monkeys, rats and mice by changing the chemical levels in their brains or by adding stress to their lives. And scientists now can prove that the disease is genetic. They can breed rats that crave alcohol, are indifferent to it, or hate it. When U.S. Department of Health and Human Services researchers set up a system in which rats were required to press a lever to get a drink, alcohol-craving rats were 10 times more likely to do so. The reason appears to be significantly different levels of two key chemicals dopamine and serotonin in the rats' brains.
Dopamine is a chemical produced in the brain that enhances pleasure.
In some rats, alcohol doesn't seem to affect normal dopamine levels. But alcohol-craving rats seem to start with a dopamine deficit, then use alcohol to stimulate the chemical. Ultimately, the brain depends on alcohol for production of dopamine, making withdrawal doubly difficult. Serotonin is another chemical produced in the brain in reaction to a food, drink or activity. In some animals, alcohol doesn't appear to trigger serotonin's effect.