On page 183 of Chasing The Scream, I write:

“It would be absurd to say the chemicals play no role at all in, say, cigarette or crack addiction. So how much really is due to the chemicals, and how much is due to the social factors? What’s the ratio?

As I read more, I stumbled across—in the work of an amazing scientist called Richard DeGrandpre—an experiment that gives us a quite precise answer, in percentage terms. You may well be taking part in it right now.

When nicotine patches were invented in the early 1990s, public health officials were thrilled. They believed in the theory of addiction that almost everyone believes in: addiction is caused by chemical hooks that are hidden in the drug. You use a drug for a while, and your body starts to crave and need the chemical in a physical way. This isn’t hard to grasp. Anybody who has tried to quit caffeine knows that chemical hooks are real: I am trying it as I type this, and my hands are very slightly shaking, my head is aching, and I just snapped at the guy sitting opposite me in the library.

Everyone agrees that cigarette smoking is one of the strongest addictions: it is ranked on pharmaceutical addictiveness scales alongside heroin and cocaine. It is also the deadliest. Smoking tobacco kills 650 out of every hundred thousand people who use it, while using cocaine kills four. And we know for sure what the chemical hook in tobacco is—it’s nicotine.

The wonder of nicotine patches, then, is that they can meet a smoker’s physical need—the real in-your-gut craving—while bypassing some of the really dangerous effects of smoking tobacco. So if the idea of addiction we all have in our heads is right, nicotine patches will have a very high success rate. Your body is hooked on the chemical; it gets the chemical from the nicotine patch; therefore, you won’t need to smoke anymore.

The pharmacology of nicotine patches works just fine—you really are giving smokers the drug they are addicted to. The level of nicotine in your bloodstream doesn’t drop if you use them, so that chemical craving is gone. There is just one problem: even with a nicotine patch on, you still want to smoke. The Office of the Surgeon General has found that just 17.7 percent of nicotine patch wearers were able to stop smoking.

How can this be? There’s only one explanation: something is going on that is more significant than the chemicals in the drug itself. If solving the craving for the chemical ends 17.7 percent of the addictions in smokers, the other 82.3 percent has to be explained some other way.

Now, 17.7 percent certainly isn’t a trivial amount. That’s a large number of people with improved lives. It would be foolish and wrong to say the drug has no effect—tobacco cigarettes are considerably more addictive than menthol cigarettes, to give just one example. But it would be equally foolish to say what we have been saying for a century—that the chemicals themselves are the main cause of drug addiction. That assertion doesn’t match the evidence.

This point is worth underscoring. With the most powerful and deadly drug in our culture, the actual chemicals account for only 17.7 percent of the compulsion to use. The rest can only be explained by the factors Gabor and Bruce have discovered.”

This week, I received an email from Garret Merriam, who is an Associate Professor of Philosophy at the University of Southern Indiana, with an important correction to this passage. He wrote:

“Dear Mr. Hari,

I have just finished “Chasing the Scream” and I enjoyed it tremendously. I found it to be thorough, engaging, fair and thought-provoking. I think it is fair to say that you have persuaded me of your core theses (but then again, I was pretty sympathetic towards them going in.) I consider myself fairly knowledgeable about this topic, but I had never heard of Harry Anslinger before. I feel a large gap in my knowledge base has been filled. For that reason, among others, I have recommended the book to several colleagues and friends.

But I did want to address the one part where I felt there was a glaring logical error in your text. On page 183 of the paperback edition you note that “The Office of the Surgeon General has found that just 17.7 percent of nicotine patch wearers were able to stop smoking.” I take no issue with that claim, but later on the same page you draw the following conclusion from this stat: “With the most powerful and deadly drug in our culture, the actual chemicals account for only 17.7 percent of the compulsion to use.”

That conclusion simply does not follow from the Surgeon General’s statistic. The figure of 17.7% refers to PEOPLE, not to amounts of their compulsion; when you draw your conclusion, you equivocate between those two very different things. It might be the case that the chemicals account for, say, 30% of the compulsion to use, BUT only 17.7% of users have the willpower to overcome the remaining 70% of the compulsion accounted for by other factors. (By the same token, the chemicals might account for more than 30%, or less than 17.7%, or somewhere in between.) We simply cannot draw conclusions about how much of the compulsion comes from the chemicals based solely on the success rates of people who can quit when the chemical is removed as a factor. All we can conclude is that 17.7% of people are capable of overcoming the non-chemical factors.

I hope that doesn’t seem too nit-picky, but I catch logical fallacies for a living, so that kind of jumped out at me. Notwithstanding this fairly small error, I again wish to express my praise for your book, as well as my gratitude to you for writing it.

Sincerely yours,”

This is a really important correction. When I was explaining this point in an interview recently, I realized there was something wrong with what I was saying – but I couldn’t put my finger on what.

Thank you to Merriam for pointing this out, and I’ll be correcting this point in future editions of the book to reflect the point he makes.

(This is also proof I should have concentrated more in my philosophy classes when they talked about logical fallacies: more Bertrand Russell, less Nietzsche…)