Can a drug be addictive if it produces no withdrawal symptoms?
In theory, yes. With the natural addictions gambling, eating, etc. you don’t experience any physical withdrawal, but you do get cravings. Cocaine doesn’t produce strong physical withdrawal symptoms, but it is highly addictive. Conversely, there are a lot of medications, such as the heart medication Inderal, that cause a clear physical dependence but are nonaddicting. How much of addiction is genetic and how much of it is social? Epidemiological studies tell us that about half the risk for addiction is genetic. And the degree of genetic vulnerability seems to be roughly the same for the various types of drugs alcohol, heroin, cocaine. To put the numbers in perspective, a 50 percent genetic risk is higher than for type II diabetes or hypertension, which we often think of as genetic diseases. Why do we have this susceptibility? The dopamine pathway probably evolved to provide an emotional reinforcement for certain choices an animal makes about food, sex, and social interaction. Drugs of a
