Dr. Volkow is the Director of the National Institute on Drug Abuse (NIDA). She is an expert on addiction and its effects on the brain over time. She pioneered the use of brain imaging to discover dopamine, a chemical released by the brain allowing us to feel pain or pleasure, is at the root of addiction. The recipient of many prestigious awards, Dr. Volkow is an accomplished author of over 500 peer-reviewed articles and 80 book chapters.
Nearly 21 million Americans, or 8 percent of the population, have a drug or alcohol problem that adversely affects their lives. People often think that those who can’t get the better of an addiction are just not exercising enough willpower. But decades of research have shown us quite clearly that once a person becomes addicted, the parts of the brain controlling willpower become impaired, making saying no to drugs difficult or sometimes impossible.
I have always been interested in the processes in the brain that allow human beings to exert free will, and how drugs ultimately undermine those processes. I was exposed to addiction growing up—my favorite uncle was an alcoholic, and I saw the shame and stigma that he faced, and his unsuccessful struggle to get appropriate medical treatment.
I went on to medical school with the plan to learn as much as I could about the brain and how it is influenced by drugs. I saw the incredible potential that neuroimaging techniques offered, so I started to use these techniques to characterize the changes that occur in the brains of addicted individuals. Over the course of my research career, including my time as Director of The National Institute on Drug Abuse, my colleagues and I have begun to map the neuronal circuits that are disrupted by the use of drugs and that result in compulsive drug consumption at the expense of everyday activities. Our research paints a complex picture about free choice and responsibility–how it is disrupted by repeated drug exposure as well as being influenced by genetics factors and cultural determinants.
Choice is based in the brain. Willfully choosing a course of action involves chemical signals in neural circuits that control what stimuli we perceive as important or desirable, that govern our anticipation of rewards, and that control our learning and higher self-control processes. Different drugs have different specific effects, but all of them cause a flood of the neurotransmitter dopamine in these brain circuits, and over time, this can significantly impair the way these circuits function. When areas of the brain like the frontal cortex and striatum are compromised (or if they are not fully mature, as in young people), a person has difficulty resisting urges, saying no to temptations, and taking the soundest, healthiest, or safest course of action.
When we scan the brains of people with addictions, we actually see long-term changes in areas of the brain that govern choice and decision making. Such people are caught in a trap: part of their brain may not like being dependent on the drug, may wish that the drug was no longer a part of their life, but the brain circuits that would, in a healthy person, step in and override the urge to take the drug have been weakened. Thus the addicted person becomes increasingly powerless in the face of the great distress caused by being without the drug. It becomes a vicious cycle: the person compulsively takes the drug, and the drug erodes their self-control circuits even further.
Addiction doesn’t happen the first time a person takes a drug, and not necessarily the second or third time—it is a cumulative process. But even when it comes to initiating drug taking, some people may not be capable as others to resist the pressures to take drugs. For example, we know that adolescents and young adults, who are faced with the most social influence from peers and other sources, have brains that are least able to resist those pressures. Those areas that govern judgment and decision making are the ones that mature last in humans—not until most people are in their mid-twenties. Also, individual differences—from genetics and other factors—mean some people have weaker self-control circuits than others, which may put them at greater risk of trying drugs and becoming addicted. There is no single predictor of addiction, but rather a combination of genetic, environmental, and developmental factors all contribute to a person’s vulnerability.
Drugs don’t absolve anyone of responsibility for their actions while under the influence. But drug addiction isn’t as simple as a person making bad choices. Rather, it reflects a disease of the very system that makes good choices possible. The good news is that behavioral therapies and medications can help addicted individuals repair their damaged self-control capacities, as long as they actively participate in treatment. But this is only the starting point. Helping those addicted to substances starts with changing our perceptions about addiction. We need to drop the stigma and recognize that people with addictions have a brain disease—they don’t just lack willpower.
To see more of Dr. Volkow, watch our interview here.