We all know addiction is a disease. It has been so classified by all the authoritative sources. The American Medical Association labeled alcoholism an “illness” back in 1967.

The Centers for Disease Control, the Diagnostic and Statistical Manual of Mental Disorders and Alcoholics Anonymous urge us to think of alcohol and drug addiction as diseases.

Great minds such as Oprah Winfrey, Russell Brand and Joe Biden agree: the then-senator even introduced a bill in 2007 called the “Recognizing Addiction as a Disease Act.” (It never came up for a vote.)

The disease theory has powerful forces behind it, has money behind it. Perhaps most important, it has a comforting thought behind it. Hey, it could happen to anyone. You’re not a morally flawed individual if you catch the flu, are you? We don’t think of people with autism, “They could beat it if they tried.”

“To reject the disease label is not to demote addiction, nor is it to diminish sympathy for the addict’s plight.”

Addiction-as-disease is in some ways a thoroughly American idea. It ties together how we approach medicine (with a precisely defined target and a definitive program to fight it) and our proudly tolerant spirit in which being judgmental is seen as a kind of vice. Plus it opens up profit opportunities from sea to shining sea.

If addiction is a disease, though, why do most addictions end spontaneously, without treatment? Why did some 75% of heroin-addicted Vietnam vets kick the drug when they returned home?

It’s hard to picture a brain disease such as schizophrenia simply going away because someone decided not be schizophrenic anymore.

Addiction is not a disease. It’s simply a nasty habit, says neuroscientist Dr. Marc Lewis, himself a longtime addict and professor of developmental psychology, in his new book, “The Biology of Desire.”

‘Exercise of the will’

Framing addiction as a disease seems like a concept perfectly suited to our times, and yet it reaches back to Aristotle. In 1913, during an era of heavy use of opiates, a book on narcotics urged doctors not to use the word “habit” because “habit implies something that can be corrected by exercise of the will…This is not true of narcotic disease, therefore it is not a mere habit and should not be spoken of as such.

“The man who is addicted to a narcotic drug is as truly a diseased man as one who has typhoid fever or pneumonia.”

In the 1950s, Alcoholics Anonymous and Narcotics Anonymous helped advance this line of thinking by calling addiction a “malady” and physical sensitivity to alcohol an “allergy.” Twelve-step groups who are rigid about the disease theory require members to adhere equally rigidly to the prescribed treatment at the risk of expulsion from the group. At times this means intolerance for individual difference and turning a blind eye to epidemiological data.

For instance, AA teaches that any use of alcohol is likely to lead to a relapse into problem drinking, but in fact there are many recovered alcoholics who return to controlled, moderate social drinking. AA’s approach isn’t right for everyone, Lewis points out.

Even worse, AA is especially fervent about instilling in members the idea that they are powerless over alcohol. This is the opposite of teaching addicts to seize control of the future. “Most former addicts,” notes Lewis, “claim that empowerment, not powerlessness, was essential to them, especially in the latter stages of their recovery.”

He adds that people with excellent reasons to feel generally powerless in life, including minorities, women, the poor and those with especially dismal family histories, are the ones most in need of reconceiving themselves as empowered individuals.

“It’s an open question,” Lewis says, “whether the disease nomenclature, partially absorbed into the AA mainstream, has alienated more members than it’s helped.”

It may be that “exercise of the will” sounds unsatisfying simple, a too-easy solution to what can be a monstrous problem. It also causes friction with a culture that extols technical knowledge — the expert-ocracy.

Reliance on experts is supported by both supply and demand sides: As customers, we love to think that if we have a particularly nasty problem, there is someone out there who knows exactly what to do. And the $35 billion addiction-treatment industry is happy to take your money to help.

Very bad habits

Proponents of the disease theory have one talking point that they love to repeat before they hurry to change the subject: Addiction changes the structure of the brain.

This may be enough to convince non-specialists, but to experts in the field the claim that altered brain structure proves the presence of disease sounds ludicrous. The brain is a plastic organ. It changes when you age. It changes when you learn a new language or a musical instrument. It changes when you fall in love. It changes when you have children. It even changes the third time you hear your boss make a dismissive comment and you start to conclude, “This guy’s a jerk.”

The brain is continuously reshaping its neural networks. It’s like the Manhattan streetscape: Some are always under construction.

“To say that addiction changes the brain is really just saying that some powerful experience, probably occurring over and over, forges new synaptic configurations that settle into habits,” writes Lewis, who was a drug addict through most of his 20s. “Addiction may be a frightful, devastating and insidious process of change in our habits and our synaptic patterning. But that doesn’t make it a disease.”

Are we quibbling over mere word choice, though — synaptic semantics?

No, because how we see addiction is critical to how we treat it. Lewis isn’t suggesting telling addicts, “It’s all in your head. Get over it.” But he views the mushrooming of rehab centers with unease: If these businesses actually succeeded in “curing” everybody, they’d have to shut down. Calling addiction a disease is meant in part to emphasize the seriousness of being in thrall to drugs or alcohol, to elevate it to the level of a noble battle with cancer.

To reject the disease label is not to demote addiction, nor is it to diminish sympathy for the addict’s plight.

“The severe consequences of addiction,” writes Lewis, “don’t make it a disease, any more than the severe consequences of violence make violence a disease, or the severe consequences of racism make racism a disease, or the folly of loving thy neighbor’s wife makes infidelity a disease. What they make it is a very bad habit.”

Rewriting your brain

Lewis delves into case studies of addicts to illustrate different strategies people use to free themselves. “Natalie,” for instance, was a nice, middle-class student at a liberal-arts college who gradually sank into a swamp of heroin.

She started on typical college drugs — pot, magic mushrooms, ecstasy. But she found opiates like OxyContin to be a big step up in satisfaction: “They didn’t pitch you into a colorful fairyland, the way mushrooms and acid did. Instead they wrapped you in a stocking of inner peace, utter relaxation. Not the kind of sedation you’d get from a tranquilizer, but something subtler and yet more potent . . . Some misty layer of anxiety was always floating above the surface of things. Until opiates took it away.”

“Natalie” turned to heroin because it was cheaper than pills, first snorting and smoking the drug. But when she saw someone shoot up, she was transfixed. She wanted to join in that ritual herself — the heating of the brown powder in the spoon, the tourniquet, the needle.

Natalie was rerouting her brain with a feedback loop, creating more and more associations with the heroin craving. Soon it became difficult to focus on anything else — job, school, family. Her connections with people outside her drug circle frayed and disintegrated. After a mishap involving a borrowed car and a failed stint in rehab, she found herself spending nine months in a maximum-security prison.

So she taught herself to meditate. It was not as simple as “deciding to get clean.” Rewiring her thinking was work. She was building new neural paths for herself and breaking up the old ones.

“We could say that Natalie chose to stop using drugs, but it’s not that simple either,” Lewis writes. “Instead, desire was rerouted. It was now in league with other goals: self-preservation, self-control, a respite from her weariness.” Natalie was educating herself as surely as someone who learns Japanese is doing so.

Natalie had to learn to overcome what Lewis calls “now appeal” — putting short-term gratification ahead of long-term thriving. When we crave something, our brains are awash in dopamine, which brings pleasure in itself. Addiction is less about enjoyment than it is about anticipation, about desire. But resisting temptation requires a lot of brain energy. At some point fatigue sets in and it becomes too exhausting not to give in.

Addicts are told again and again to resist, by counselors, therapists, friends and relatives. Just say no!

“Yet the research tells us unambiguously,” writes Lewis, “that suppression is the wrong way to go, because it accelerates ego fatigue.’

Achieving mastery over yourself requires instead a shift of perspective and a reinterpretation of your emotional state. “Instead of tying yourself to the mast in order to resist the Sirens’ song, you must recognize the Sirens as harbingers of death and reframe their songs as background noise,” Lewis says.

The ability to resist “now appeal” is thought to be centered in the left dorsolateral prefrontal cortex, which is more developed in mature adults. That’s why addiction is so often associated with youth. There is some evidence that people who learn to beat addiction are developing that area of the brain, as you might work on building up your triceps.

Embracing a future

Drugs can help by suppressing cravings or easing withdrawal symptoms, but getting free of addiction is fundamentally a process of internal development, Lewis argues. In case studies he presents in the book, he explains how honest personal reflection, reconnecting how past behavior led to current predicaments and imagining a different and better future were instrumental to successful outcomes for addicts.

“[The brain]… is like the Manhattan streetscape: Some are always under construction.”

Addiction isn’t a direct result of a stress-filled childhood, but there is close correlation between the two, and a survey that explored high youth suicide rates in some Native American areas of Western Canada found that in such communities young people were “incapable of talking about their lives in any coherent, organized way,” Lewis says. “They had no clear sense of their past, their childhood, and the generations preceding them. And their attempts to outlines possible futures were empty of form and meaning. They simply could not consider their lives as narratives, or stories.”

To Lewis, there’s a clear lesson here.

“Humans need to be able to see their own lives progressing, moving from a meaningful past to a viable future. They need to see themselves as going somewhere, as characters in a narrative.”

Life’s a book; write the next chapter yourself.