If anything deserves to be called “the establishment view,” it is what Johann Hari — in his new book on addiction and the war on drugs, Chasing the Scream: The First and Last Days of the War on Drugs — calls the pharmaceutical model of addiction.

The pharmaceutical model says that addiction is about chemicals. Addiction is a chronic incurable disease of the brain. The brain’s pleasure centers are hijacked.

The pharmaceutical model may be the conventional wisdom, but it is certainly not without controversy. Researchers such as Gene Heyman and Bruce K. Alexander have long questioned whether the data support this picture.

As Hari reminds us, heroin use was rampant among U.S. soldiers stationed in Vietnam during that conflict. According to one study he cites, 20 percent of these American servicemen were heroin users. Over 85 percent of these users gave up heroin when they got home, the book says; they simply stopped taking the drug.

How do we reconcile this fact with the idea that the drug hijacks the brain and takes over? If that’s true, you wouldn’t expect a change of scenery (coming home from Vietnam) all by itself to break the neuro-chemical stranglehold. Alternatively, you might speculate that perhaps these heroin users were not really addicted. That the fact that they stopped proves this. But then we face a new problem: If the addiction is a chemical effect of the drug, then why weren’t they addicted?

Indeed, as Heyman claims in his book, there is good evidence that most addicts in the general population, as a matter of fact, eventually stop using drugs. They stop because they get to a point where they want or need or find that they are able to stop. They decide to stop. Now, this doesn’t fit very well with the conventional wisdom. You can’t simply decide to give up other diseases like diabetes or heart disease!

Or consider the fact that, as Hari explains, actual chemical dependence seems to be only a small part of drug addiction. If addiction were just about chemicals, then you would expect that the availability of nicotine patches — which can deliver smokers every bit of the nicotine they would get from a cigarette — would, in one fell swoop, eliminate the feeling that one needs to smoke. But not so. Only 17.7 percent of smokers using nicotine patches, according to Hari, break their addiction to smoking.

Hari also describes a fascinating reverse case. At some point in the 70s, heroin interdiction in Vancouver was so effective that there was virtually no heroin on the streets. This didn’t stop dealers from selling white powder and calling it heroin, and it didn’t stop addicts from hustling to get their hands on this powder so that they could shoot up. If it is the chemical itself that drives addiction and controls the addict, then you would have expected that Vancouver’s junkies, deprived of real heroin, would have been weened of their dependence.

That this didn’t happen is striking evidence — assuming the anecdote, originally reported by Alexander, is true — that not only is the chemical itself not sufficient to explain addiction, it isn’t even necessary.

Data like these suggest that addictions, although they no doubt interact with neural chemistry, can’t adequately be understood alone in neuro-chemical terms. And this is because it is people, not brains, that get hooked. To understand the actions of addicts, you need to look at their lives as a whole. When doctors claim, as they do, that addiction is a disease of the brain, they are saying something that is either trivially true (that the brain plays a role in addiction) or something entirely false (that the brain is the whole story).

It is true, as the old commercial made vivid, that a rat in a cage will forego water to self-administer morphine every time — and will continue to do so until it is dead. But, maybe, it’s not the morphine that best explains this but, rather, the fact that the sorry rat is locked up exposed, in complete isolation from its fellows, in an otherwise empty cage.

This observation led Alexander to wonder: Would a rat in a richer environment — one including not only water and morphine, but also other rats and good food and interesting landscapes — take the same self-destructive course of action? Or, rather, would this other rat find itself so totally dominated by the rewards that the drug alone provides? To investigate this, Alexander designed “rat parks” that were much larger, interesting and hospitable environments in which communities of rats were placed. He found that happy rats in happy rat parks behaved more like casual human drinkers than liked crazed addicts, in that they limited themselves to small amounts of morphine.

This result is striking — and it certainly corresponds to my own personal experience of addiction. I have known addicts, but I have known many more drug users who were not addicted.

Now, Hari is convinced that Alexander has unlocked the true essence of addiction. Addiction is caused by isolation. And the cure for addiction, it follows, is love. We need to give the addict back his or her feeling of connection to others.

This is a beautiful idea — and I like beautiful ideas. I also think that it gets something right. Addicts are disconnected and isolated. But we need to be careful in drawing a too-speedy conclusion. The fact that being isolated is a cause of addiction doesn’t yet clarify how sociality, love, friendship, isolation, etc., function in the lives of addicts. In particular, it doesn’t mean that you can fix addiction with love.

One reason love might not be all you need is that it could be that the wounds that lead us to turn to drugs, to really give ourselves over to drugs, might have their roots in our early lives. It’s hard to simply “get over” early childhood trauma. (Hari also celebrates the work of Mate Gabor, a clinician who argues, in ways that some thinkers worry might be a bit reductive, that the sources of addiction lie in trauma.)

But there is a deeper reason to worry that love couldn’t suffice. Whatever its causes, addiction would seem to be — something like this is Heyman’s view — a disorder of one’s ability to connect to others and value the things that human beings tend usually to value (such as food, exercise, sex, family, work). The remarkable and striking thing about many addicts is that they opt for self-medication over encounter — they turn inward and shut out the world.

It might be right, as Hari claims, that we would fix addiction if we could restore in the addict a sense of connection with the world around him or her, and with other people. But that’s not a prescription as much as it is a statement of the problem. Addicts are shut off.