Only the weak become addicted. If that's what you think, Dr. Nora Volkow is determined to change your mind. The director of the National Institute of Drug Abuse (NIDA, part of the National Institutes of Health) and one of the country's leading addiction researchers, Volkow says brain science is proving that we all have the potential to become addicted to something: drugs, alcohol, tobacco, sex, gambling, even food. And while we may think that being addicted to food is not as bad as being addicted to heroin, researchers are learning that all addictions are more alike than was previously thought. Becoming an addict is more a matter of chance than we ever realized; mix the right combination of genetics and life experience, and anyone could find himself addicted to something.
Many people might consider that idea unsettling. Volkow finds it fascinating and encouraging, because it means everything we learn about one type of addiction has the potential to teach us something about the others. "Just imagine," she says, "if all the private money being spent to understand and treat obesity could help us understand and treat alcoholics and drug addicts." Millions of people could be pulled back from the abyss.
Volkow, the great-granddaughter of Leon Trotsky, grew up in Mexico, in the home where the Russian revolutionary was assassinated in 1940. As a young scientist, she became intrigued with the loss of free will that characterizes addictions, including the alcoholism that bedeviled her uncle. "We all think we can control our actions," she said. "But why does one person have such intense cravings that they experience a loss of control, while another person can overpower those desires? I wanted to understand the brain mechanism that makes people lose control."
Over the course of the past three decades, Volkow, 50, has published more than 420 papers, many of them on different aspects of addiction. She brings an intense, passionate advocacy for addicts to her role as head of NIDA. She is steering her agency to use breakthroughs in one area to advance research in others. In the next year, she predicts, we'll see progress in new treatments, such as drugs designed to disrupt and weaken an individual's memory of how good an addictive substance feels. "If we could interfere with that conditioned response, we might be able to weaken the addiction," she said. In effect, she says, this research is like trying to get Pavlov's dog to stop salivating when it hears the bell.
Using biofeedback as a way to control cravings is showing promise, she said, as are clinical trials now underway for a cocaine vaccine. (Antibodies would be created to protect against the effects of cocaine, similar to the way an antibiotic fights off bacteria.)
Much of the research into addiction revolves around dopamine, the neurotransmitter associated with pleasure. New research by Volkow and others indicates that high levels of dopamine receptors (which are like docking stations in the brain for dopamine) seem to protect against addiction, while low levels increase vulnerability. High levels of dopamine receptors also seem to protect against obesity and drug abuse.
"High levels of dopamine receptors seem to make us more sensitive to natural reinforcers," such as our codes of moral, social or personal behavior, says Volkow. That means it's easier for us to balance our desire for pleasure with our desire to achieve social closeness, career success or other positive life goals. Low levels throw off that balance. And some substances, including many illegal drugs, actually change the brain over time by strengthening some connections and weakening others, until taking drugs becomes the most imperative need in an addict's life. "Drugs are a more powerful reinforcer than anything else, even sex," says Volkow. "That's why people will even steal to get the money they need for drugs. That's one of the unfortunate consequences of a pathology in the brain that makes us lose our judgment, our values."
One of the main challenges going forward, she said, it to figure out how to increase dopamine receptors in those with low receptor levels. It appears that levels are affected by both genetics and experience; for example, animal research indicates that receptors decrease when the subject experiences high levels of stress, and go up when the stress is relieved. Whether that will hold true in humans, and whether some people are more sensitive to this reaction under stress, is as yet unknown.
But Volkow says that may explain why some can drink or use a drug for years and not get addicted, but "then something tragic happens, and they become vulnerable. Some people are born with a great vulnerability; for others, it takes years and years, until their environment and genetics collide in an adverse way," she says.
Volkow hopes that as we learn more about addiction, curing it will become a higher priority. "I've never met anyone who thought they would become addicted," she says. "They always say that this is the last thing they thought would happen to them, because they have such a strong will. But this disease robs you of free will. The challenge is to find a cure."