“The brain would be useless if it weren’t highly changeable,” Dr. Marc Lewis, author of the upcoming book The Biology of Desire: Why Addiction is Not a Disease, told me in an interview. A line that sounds so simple doesn’t seem to poke logical holes in the accepted notion that addiction is a “chronic, relapsing brain disease.”

But this is precisely the essence of the on-going argument between dozens of esteemed scientists, who cannot seem to agree on what addiction is, and how it ought to be classified.

On the one hand, there’s the medical establishment’s view, led by Dr. Nora Volkow of the National Institute on Drug Abuse (NIDA). Volkow argue s that addiction is “a brain disease because drugs change the brain…These brain changes can be long lasting and can lead to many harmful, often self-destructive, behaviors.”

Neuroscientists like Dr. Marc Lewis see things differently. He writes in a section on neuroplasticity that, “neuroscientists who study addiction seem to have missed the point. They put people through a number of brain scans, and when they notice changes after someone has taken a lot of cocaine or drunk a lot of booze they say, ‘Look! The brain has changed!’”

This is an unremarkable observation, Lewis says. Since it is true of intensive learning in general, it does not amount to evidence of a diseased brain. So how can neuroscientists who look at the same brains in the same imaging studies come to fundamentally different interpretations?

“The point at which we call something a disease, where we draw this line in the sand, is arbitrary,” Lewis said. “It depends a whole lot on societal values and morals, rather than on any kind of logical, scientific or other rational criteria.”

What gives Lewis an edge are his impeccable, Oliver Sacks-like case studies sprinkled throughout the book, which demonstrate his understanding of and fascination with the experience of drug users. Where many neuroscientists see subjective experience as messy and immeasurable, Lewis looks to fill the sizeable gap between neuroscientific inquiry—blood, membranes, and molecules—and one’s subjectivity.

And of course, Lewis affirms, like his neuro-contemporaries, that drug abuse does have major effects on the brain, especially in prefrontal areas used for judgment and decision-making, and in the dorsal striatum, a region implicated in learning habits. But those changes, he says, are not permanent and irreversible, as Volkow and NIDA suggest.

Lewis’ argument hinges on the concept of neuroplasticity, namely— the concept that the brain adapts to new behaviors by forming new neural pathways. “The idea that brain configurations are hardened and sealed is just ridiculou s,” says Lewis. “It makes no sense in the current scientific environment.”

In an early section of the book Lewis writes that classifying addiction as an incurable brain disease may be harmful to addicts themselves. Dr. Volkow of NIDA argues the exact opposite, that labeling addiction as a disease removes the shame, stigma, and blame from the drug user.

When I pressed Lewis on this very issue, he said, “The disease label often leads to a sense of fatalism: ‘I’ve got a disease, what can I do? I need to go get help and if I can’t get better it’s because I have a disease.’”

In contrast, he went on to say, many who work with drug users see empowerment, self-discipline, and intense self-reflection as the only way to beat an addiction.

This is a controversial stance. Notions such as empowerment run contrary to Alcoholics Anonymous’ first step of admitting powerlessness. Some 90 percent of addiction treatment facilities in America operate within the 12-Step paradigm.

In his book, Lewis suggests a drastic rethinking of how we frame the entirety of addiction—down to revising the word “recovery,” one he believes to be “ill-founded because of its medical connotations” and the implications that may have on addicts. “Why should we call it ‘recovery’ if it’s the beginning of something new?” he says.

Lewis is careful to note, however, that his intention is not to denigrate the term for those who find meaning in it. Still, he contends that the term means little in scientific discourse, because people don’t go back to normal. He believes in people, and that a person keeps growing and changing, eventually becoming someone beyond the person she or he used to be before ever having used substances.

To ground this notion, he cites a study where grey matter volume returned to a healthy baseline level within six months to a year of abstinence in cocaine, heroin, and alcohol users.

“Here comes the first surprise,” he writes, “grey matter volume in these regions continued to increase...It makes sense. Abstinence requires sustained and seasoned cognitive effort, and that effort grows synapses as surely as any other motivated activity.” "The second surprise is that...the regions of increased growth don't correspond exactly with the regions initially depleted."

He asks us to interpret this finding with caution, as future research is needed, but the results of this study “could mean that recovering addicts don’t just regain their lost self-control; they actually develop entirely novel strategies for self-control, based on newly acquired neural terrain.” Hence, “recovery” may be a misnomer.

It’s also asked of us to look at how addiction is currently treated. “The most effective tools target cognitive and motivational processes such as self-determination, insight, willpower, and self-forgiveness. There is no disease that can be arrested by tapping such processes.”

Diseases are often treated by medical interventions, with pills, implants, and surgeries. Addiction is just not treated that way— at least no such methods have proven to be successful yet. Until such approaches do work, addiction is still an all too human dilemma, and as Lewis says, it takes activities that are uniquely human to overcome it.

So if not a disease, then what is it? Lewis, simply put, says that it’s a habit—one that’s incredibly powerful, destructive, potentially life wrecking, and extra difficult to break. But with the right help and determination, Lewis believes people can overcome such habits and come out on the other side a stronger human being.

The last thing the two of us discussed was how both of us did exactly that, just two former drug abusers, sitting down for a chat.