I first met Marc Lewis, PhD, on a Skype call. He spoke to me from Arnhem, a small city in the Netherlands, where he lives. He looks the part of a college professor, with a neat silver beard and black-rimmed glasses. Dr. Lewis is instantly likeable, perhaps not exactly the person I’d expect to espouse hotly debated ideas about addiction. In specific, those who staunchly support the disease model of addiction take exception to Lewis’ beliefs that addiction is in fact not a chronic disease of the brain, the widely held view among those who treat addiction today.
Lewis, who is a neuroscientist and professor of developmental psychology at Radboud University in the Netherlands, is not, he says, a lone wolf. He says that while changes do occur in the brain when someone is using a substance — there’s no question about that — these changes are not the result of a chronic brain disease but result from the brain learning to abuse drugs. This topic is the focus of a thorough investigation in his new book, The Biology of Desire: Why Addiction Is Not A Disease, out today.
Like many other specialists in addiction, during our interview Lewis concedes that treatment for addiction is still very much in its infancy. We’re just beginning to scratch the surface of understanding what addiction is and what causes it, let alone how to treat it in the most effective and safest ways possible. But without consensus (or something close to it) about what causes addiction, it is hard to agree on a cure, if one is even possible. So the debate about the cause(s) of addiction is tremendously relevant.
In his new book, Lewis outlines three major models of addiction, including the disease model, which currently leads the pack. This model holds that addiction is a chronic disease, much like diabetes or heart disease. The two other predominant explanations for why addiction happens are choice (people choose to misuse drugs) and self-medication (that addicts are numbing the pain of trauma and unmanageable emotions and/or escaping them through the high offered by their drug of choice). Lewis puts his support staunchly behind a fourth possibility: learning, meaning the brain changes that occur are due to a learning process. “In addiction, what you are learning is that a certain substance or activity can make you feel better,” he explains in a recent email. “You learn an orientation, an attraction, a promise of relief.
The Disease Model Explained
An outspoken and highly visible proponent of the disease model theory in the U.S. is Nora Volkow, MD, head of the National Institute on Drug Abuse (NIDA). The NIDA website, in fact, makes this point of view clear in its definition of addiction: “Addiction is defined as a chronic, relapsing brain disease that is characterized by compulsive drug seeking and use, despite harmful consequences.”
Addicts develop the disease by taking illegal drugs that release dopamine, the neurochemical that elicits a high or feeling of euphoria, and also over time the way the brain processes dopamine changes as well. Lewis notes that the U.S. medical community — the National Institutes of Health, American Medical Association and the American Society of Addictive Medicine — pretty much universally supports the disease model. In attending a 2014 event with the Dalai Lama, Dr. Volkow and Lewis debated their respective theories, which he details in The Biology of Desire. Lewis sums up the encounter by saying, “we agreed to disagree.”
The Learning Model
Lewis explains his view of how we can learn to be addicted this way: “The brain is designed to change. The brain changes massively in [childhood and adolescent] development, it changes when you fall in love, it changes when you learn to play the violin,” he says. So, he says, of course it also changes when you take drugs over time. (Lewis’ book is also critical of the fact that the medical community sees addiction as being caused by mainly substances when porn, sex Internet games, food and gambling activate the brain in a way that’s almost identical to the way drugs do — what he calls an overreaction of the striatum.)
What’s more, he says, the transformations within the brain that occur from using a substance are not pathological. “Actually, they’re not that different in the quality or kind or location than brain changes that occur when people fall in love,” he says. “The brain change [that happens in addiction] should be considered a developmental process, a developmental phenomenon, a learning phenomenon — not a disease.”
According to Lewis, addiction develops like pretty much any habit. “Bad habits like addiction grow more deeply and often more quickly than other bad habits because they result from feedback fueled by intense desire and because they crowd out the availability or appeal of alternative pursuits,” he explains. “But they are still, fundamentally, habits — habits of thinking, feeling and acting.”
So how, exactly, is learning involved in brain changes when someone takes drugs or becomes addicted to a behavior like watching porn or gambling? Lewis claims our brains are designed for learning and also designed to change with our environment. He writes that “desire is evolution’s agent for getting us to pursue goals repeatedly.” Desiring a drug leads us to repeat drug-taking behavior, which modifies “synaptic networks,” the web of connections among neurons in the brain. So when we intensely want or crave something and we repeat the behavior of acquiring it, that accelerates the rate of learning and habit formation. So taking drugs, drinking, gambling and/or playing video games becomes a habit because it’s something we learned to do through repetition driven by desire.
The Origins of the Disease Model
The author spends considerable space in The Biology of Desire detailing where and how addiction as a disease originated. The idea dates back to Aristotle as well as other scholars in the ancient world. The theory took hold in the West in the early 1900s, he writes, quoting a 1913 document: “The man who is addicted to a narcotic drug is as truly a diseased man as one who has typhoid fever or pneumonia.” By the 1930s, Alcoholics Anonymous (AA) was calling addiction a mental and spiritual “malady.” And in 1967, the American Medical Association classified alcohol abuse as an illness. As recently as 2007, vice president Joe Biden called for the Recognizing Addiction as a Disease Act (the bill was not enacted). Today, the disease model is widely accepted in the U.S. and around the world, and it does have the most scientific research to back it up.
Lewis comes to the field of addiction science not only as a neuroscientist and professor; he was himself addicted to drugs in his 20s. (He shared this in a previous book, Memoirs of an Addicted Brain: A Neuroscientist Examines His Former Life on Drugs.) “I’m convinced that calling addiction a disease is not only inaccurate, it’s often harmful,” Lewis writes in The Biology of Desire. “Harmful, first of all, to addicts themselves. While shame and guilt may be softened by the disease definition, many addicts simply don’t see themselves as ill and being coerced into an admission that they have a disease can undermine other — sometimes highly valuable — elements of self-image and self-esteem. Many recovering addicts find it better not to see themselves as helpless victims of a disease, and objective accounts of recovery and relapse suggest they might be right.”
He says there’s also another, more insidious reason why the disease model isn’t going anywhere anytime soon, at least in the U.S.: It enables drug and alcohol treatment centers to bill for treatment as a medical disorder, which means it can be reimbursed by insurance companies. “The disease concept is also a useful tool for the insurance industry because it defines and delimits the kind of treatment that will and won’t be covered, for how long, and at what cost,” he says on our Skype call. And, he readily admits, messing with the current payment system could be harmful to those who need treatment. “The problem if people take this [learning] argument seriously — and I’m not the only one — is that it’ll pull the rug out of insured addiction treatment,” he says. “Of course, I don’t want that. I want addiction treatment to be more advanced, more sensitive, more valid, more useful.”
Profile photo courtesy of Marc Lewis, PhD; book cover photo courtesy of PublicAffairs