Wednesday, November 30, 2011

Alva Noë - Addiction Is Not A Disease Of The Brain

This article by Alva Noë was posted a couple of months ago at NPR's 13.7 Cosmos and Culture blog, but I had not got around to sharing it yet. Noë is making an argument, with which I agree, that addiction is not simply about brain chemicals but, rather, it is a whole person issue. He followed this article with another one in which he looked at Gene M. Heyman's 2009 book on addiction - I've included that one as well.
circa 1870:  Anatomical drawing of a man's brain and cerebral nerves.

Addiction has been moralized, medicalized, politicized, and criminalized. And, of course, many of us are addicts, have been addicts or have been close to addicts. Addiction runs very hot as a theme.

Part of what makes addiction so compelling is that it forms a kind of conceptual/political crossroads for thinking about human nature. After all, to make sense of addiction we need to make sense of what it is to be an agent who acts, with values, in the face of consequences, under pressure, with compulsion, out of need and desire. One needs a whole philosophy to understand addiction.

Today I want to respond to readers who were outraged by my willingness even to question whether addiction is a disease of the brain.

Let us first ask: what makes something — a substance or an activity — addictive? Is there a property shared by all the things to which we can get addicted?

Unlikely. Addictive substances such as alcohol, heroin and nicotine are chemically distinct. Moreover, activities such as gambling, eating, sex — activities that are widely believed to be addictive — have no ingredients.

And yet it is remarkable — as Gene Heyman notes in his excellent book on addiction — that there are only 20 or so distinct activities and substances that produce addiction. There must be something in virtue of which these things, and these things alone, give rise to the distinctive pattern of use and abuse in the face of the medical, personal and legal perils that we know can stem from addiction.

What do gambling, sex, heroin and cocaine — and the other things that can addict us — have in common?

One strategy is to look not to the substances and activities themselves, but to the effects that they produce in addicts. And here neuroscience has delivered important insights.

If you feed an electrical wire through a rat's skull and onto to a short dopamine release circuit that connects the VTA (ventral tegmental area) and the nucleus accumbens, and if you attach that wire to a lever-press, the rat will self-stimulate — press the lever to produce the increase in dopamine — and it will do so basically foreover, forgoing food, sex, water and exercise. Addiction, it would seem, is produced by direct action on the brain!

(See here for a useful Wikipedia review of this literature.)

And indeed, there is now a substantial body of evidence supporting the claim that all drugs or activities of abuse (as we can call them), have precisely this kind of effect on this dopamine neurochemical circuit.

When the American Society of Addiction Medicine recently declared addiction to be a brain disease their conclusion was based on findings like this. Addiction is an effect brought about in a neurochemical circuit in the brain. If true, this is important, for it means that if you want to treat addiction, you need to find ways to act on this neural substrate.

All the rest — the actual gambling or drug taking, the highs and lows, the stealing, lying and covering up, the indifference to work and incompetence in the workplace, the self-loathing and anxiety about getting high, or getting discovered, or about trying to stop, and the loss of friends and family, the life stories and personal and social pressures — all these are merely symptoms of the underlying neurological disease.

But not so fast. Consider:

All addictive drugs and activities elevate the dopamine release system. Such activation, we may say, is a necessary condition of addiction. But it is very doubtful that it is sufficient. Neuroscientists refer to the system in question as the "reward-reinforcement pathway" precisely because all rewarding activities, including nonaddictive ones like reading the comics on sunday morning or fixing the leaky pipe in the basement, modulate its activity. Elevated activity in the reward-reinforcement pathway is a normal concomitant of healthy, nonaddictive, engaged life.

Neuroscientists like to say that addictive drugs and activities, but not the nonaddictive ones, "highjack" the reward-reinforcement pathway, they don't merely activate it. This is the real upshot of the rat example. The rat preferred lever-pressing to everything; it dis-valued everything in comparison with lever-pressing. And not because of the intrinsic value of lever-pressing, but because of the link artificially established between the lever-pressing and the dopamine release.

If this is right, then we haven't discovered, in the reward reinforcement system, a neurochemical signature of addiction. We haven't discovered the place where addiction happens in the brain. After all, the so-called highjacking of the reward system is not itself a neurochemical process; it is a process whereby neurochemical events get entrained within in a larger pattern of action and decision making.

Is addiction a disease of the brain? That's a bit like saying that eating is a phenomenon of the stomach. The stomach is an important part of the story. But don't forget the mouth, the intestines, the blood, and don't forget the hunger, and also the whole socially-sustained practice of producing, shopping for and cooking food.

And so with addiction. The neural events in VTA clearly belong to the underlying mechanisms of addiction. They are necessary, but not sufficient; they are only part of the story.

Remember: normally there is a dynamic quality to our actions and preferences, just as there is with those of rats. We enjoy exercising, but we soon get tired or bored. But rest, too, soon loses its appeal. We eat, and then we are sated. And then we are ready for the tread mill again. And so on. Things have gradually changing and complementary values. In addiction, this dynamic goes rigid. The addicts goal assumes a fixed value, and the value of everything shrinks to zero, and with terrible costs.

Our strategy was to look for systematic effects that all and only the addictive drugs and activities have on addicts. And we've found what we were looking for. The effects are behavioral and experiential. The things that addict us all produce a very distinctive breakdown in the organization of our preferences, actions and choices.

Is addiction a disease of the brain? This strikes me as a dubious falsification of what is, really, a phenomenon that can only be understood in terms of the life, choices, needs and understanding of the whole person.

Here is the second article:

A Chinese chef demonstrates his cooking skills to visitors during the 12th Asian International Exhibition of Food and Drink, Hotel, Restaurant & Foodservice Equipment Supplies & Services (HOFEX) at the Hong Kong Exhibition Center in 2007.

"Shall I have Chinese food tonight, or Italian?

I like Chinese more, but I had it last night, and I find that I enjoy it less if I have it two nights in a row. And anyway, I guess I'm kind of in the mood for Italian."

This imagined interior dialog brings out an interesting fact about values, preferences and choices. I may prefer one thing to another (Chinese food to Italian), but the current value of my preferences fluctuates dynamically as a response to my actions and past choices. If I eat Chinese food every night, the value to me of those meals will gradually reduce to zero.

This is a general truth about life and choice. Exercise is wonderful, until you get tired; rest is wonderful, until you get bored, and then restless. In a good life — if I can be permitted such a phrase — there is a kind of interplay and balance in the dynamic of shifting values, preferences and choices. What we like and want affects what we do; what we do in turn affects what we like and want.

The Chinese food example comes from Gene M. Heyman's 2009 book on addiction; Heyman makes an interesting observation in this connection. It isn't only the case that our choices and actions bring about dynamic fluctuation in the values we place on things; it is further the case that there are always different ways of framing the choice problems that we face.

So consider the dining example again and notice that there are two different ways I might reason about the question what should I eat? According to the first way, I say to myself: what do I want to eat now? Chinese, or Italian? If I take this local approach, I am likely to tend, over time, to alternate nightly between Chinese and Italian cuisine (perhaps, given my antecedent preference for Chinese food, with a slight tendency to eat Chinese more often).

But there is also a global approach available to me. Instead of thinking of the choice I face on a meal-by-meal basis as a choice about what to eat right now given what I want right now, I might ask myself: how can I get the most out of my meals by planning a series of meals? And if take up this global perspective, I am likely to be led to a very different conclusion about what to do. After all, from this perspective it may become immediately clear that the way to get the most out of my meals is by eating fewer Chinese than Italian meals, not because I like Chinese less, but because I like it more, and because I realize that I can enhance my pleasure in the Chinese food I do eat by eating it less often. The local perspective leads me to eat approximately equal amounts of Chinese and Italian food; the global perspective leads me to eat more Italian than Chinese. And even though I like Chinese food more, by eating it less, I maximize my overall eating pleasure.

There's a lot to be said for the global perspective. It's smart. It's rational. And, as Heyman lays out convincingly, it may lead to an outcome which is better over all (that is, I get more pleasure from what I eat). Of course, the local perspective is much easier to take up. On the local perspective, we simply respond perceptually to the options before us here and now. What do I want to eat, now? Taking up the global perspective requires discipline; we need step back and think about the best course of action. We need to abstract away from present impulse.

Whatever we say about the relative merits of local versus global perspectives, the critical thing is this: values are dynamic and the choices we make affect not only what we do but the pleasure we take in what we do.

When Heyman says that addiction is a disorder of choice — this is the title of his book, Addiction: A Disorder of Choice — he does not mean that addicts are weak willed or that they make dumb choices. This is not a blame-the-victim book. He means something different, something subtle. His point: the distinctive hallmark of addiction is the fact that in addiction the normal interplay we've just been contemplating between choice, value and preference breaks down.

And this is because addictive substances are, in Heyman's phrase, behaviorially toxic. They neutralize the value of everything else. Work, sex, food, friendship, children — looked at locally, nothing outweighs the value the addict places on his desired substance. If I take up the local perspective on whether I should consume my drug or go to sleep, or exercise, or make love, the drug will win out every time. Addictive behavior is the natural outcome of taking up the local perspective in the presence of behavioral toxicity.

Of course the more I use my drug, the more I come to tolerate its effects, and so the less pleasure an episode of drug use can afford me. This suggests that if I were to take up the global perspective, it would lead me in the direction of abstinence. After all, from the global perspective I'd realize that by using the drug less, the pleasure of using drugs would go up; abstaining from drug use would also enhance the pleasures of non-drug activities. From the global perspective it becomes clear that I'd be a happier drug user to the extent that I minimized my use of drugs.

Why doesn't the addict take up this global perspective? And why doesn't this give him or her a route to abstinence? Why can't the addict manage this? This is an interesting and important question. And it is, of course, tantamount to the question: Why is the addict addicted? What is it to be addicted?

And now we come to the main upshot of Heyman's discussion, an upshot which is as provocative as it is, in a way, modest. The idea is this: if we are to understand addiction, we must view it precisely in this setting where wants, values, preferences and choices are in play. Addiction is in this sense a disorder of choice.

To say this is not to deny that addiction is a disease, although it is to put pressure on what we mean by disease. Nor is it to deny that addiction has critical neurological aspects. Indeed, as we discussed last week, it is doubtless that the mechanism whereby addictive substances produce their behaviorally toxic effects are in part neurological. What Heyman's proposal does rule out, though, is the idea that we can understand addiction apart from the setting of a person's dynamic life as an agent. And for this reason, I believe, it rules out the now familiar reductive dogma that addiction is a disease of the brain.

Here is a remarkable yet rarely remarked fact about addiction. Only a very small portion of drug users are drug addicts. About 15 percent of people who drink develop alcoholism; about 10 percent of those who experiment with drugs become drug addicts. (See Heyman's book for the references.)

Why is this? What governs these outcomes?

Genetic and neurological factors may play an important role. But perhaps there are other choice-related factors that play a role as well. Here's a possibility: as Heyman informs us, the majority of addicts are single; moreover, no one is better positioned and more motivated to resist the addict's problem than his or her spouse. Having a spouse raises the costs of addiction and may be a factor, a choice-pertinent factor, in predisposing someone to avoid the trap of addiction.

It may even help the addict break free from addiction. For there is a second remarkable but rarely noticed fact about addiction (again, see the book for the details). Despite the oft-chanted dogma that addiction is a chronic incurable disease of the brain — "once an addict always an addict" — the best data available clearly demonstrates that more than 75 percent of hardcore drug addicts will eventually cease to take drugs and that they will do so without having received treatment. How can this be? What could explain this? And what determines who breaks free from the trap of addiction and who fails to do so?

If Heyman is right, we might hope to find the answer to these questions by turning our attention not to the nervous system of the addict, to his or her internal life, but rather to the pattern of needs, options, values, preferences and pressures that structure the person's ongoing life in a community with others.

You can keep up with more of what Alva Noë is thinking on Facebook and Twitter.

No comments: