So You Think That Sibling Study in <i>Science</i> Proves Something About Addiction?

Let's grant that we can reduce impulsivity to a single brain structure (which isn't itself true). Instead of saying this study provides evidence that addiction is inborn, it is equally true -- truer -- to say that it suggests that impulsivity and brain structure have no impact on addiction.
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Have you heard about the earth-shaking new study "proving" that addicts inherit a brain dysfunction that causes them to have poor impulse control? Published in the most prestigious fundamental research journal in the world, Science, investigators at Cambridge found that siblings, half of whom were drug-abusers/addicts and half of whom were not, shared this trait. This proved to the researchers that the brain anomaly preceded the drug abuse, and was not a result of it.

Here, let's turn to Nora Volkow (as Science itself did) for an explanation:

"The inferior frontal gyrus is really one of the main 'brakes' of our brain," says Dr. Nora Volkow, director of the National Institute on Drug Abuse, who wrote a commentary accompanying the study in Science. "[Drug users and their siblings] have less connections that are linking the rest of brain with the inferior frontal gyrus [and other key regions] that form a network that allows you to inhibit responses."

Run that by me again. A study showing a brain dysfunction that somehow causes addiction led half of siblings to drug abuse but not the other half? Doesn't that make us want to learn what accounted for the siblings with the brain anomaly not becoming addicted?

The most casual reading of these results points to a fundamental problem with the conclusion that brain function causes addiction. Let's grant that we can reduce impulsivity to a single brain structure (which isn't itself true*). Instead of saying this study provides evidence that addiction is inborn, it is equally true -- truer -- to say that it suggests that impulsivity and brain structure have no impact on addiction. After all, only a coin flip could tell you the chances of two people who share these traits becoming addicted or not.

Really, the study -- since it measured no natural populations -- tells us nothing about whether this brain condition is any more prevalent in addicts at large than it is in non-addicts. (Do you remember the ballyhooed 1990 study in the Journal of the American Medical Association that found the gene for alcoholism and addiction in one group of alcoholic cadavers? It was never replicated among any general alcoholic-addict population.)

Nothing daunted, Volkow (as described by addiction reporter Maia Szalavitz for Healthland) builds a whole edifice on such nothingness:

But the big question, as Volkow points out, is why the siblings in the current study ended up following such different paths when they shared the same vulnerabilities to addiction. Why did one become addicted, but not the other?

Additional results from the brain scans may provide intriguing hints at an explanation. For instance, people with addiction -- but not their siblings -- showed decreased activity in their medial orbitofrontal cortex (OFC). "That area is crucial in terms of enabling you to have flexibility and to shift your behavior as a function of changes in [the] environment," says Volkow.

Well, that explains it, doesn't it? To account for why some impulsive people abuse drugs and some don't, Volkow offers their (hypothetically) deficient functioning in another area of their brain. These poor souls are doubly diseased!

Ain't science grand? I'm being ironic, of course -- this isn't science. It's as though, having found something in the brain -- but something not able to account for addiction -- the writer doubles down on her brain-behavior bets. This is known as reductionism: the ironclad belief that describing events in biological terms comprises a scientific advancement no matter how hypothetical the explanation is and how little it improves our understanding of -- or ability to influence -- outcomes.

And reductionism is catchy. Forbes magazine's coverage of the Science study purported to defy its results: "Your Brain May Be 'Wired' For Addiction (But You Don't Have To Surrender)." But it actually reified them by fantasizing that the resiliency against addiction in half the subjects must have stemmed from some yet-to-be discovered "variations in the brains of the un-addicted siblings."

Brains, brains, brains. Nothing in the addicts' and non-addicts' lived experiences had any impact? The researchers carefully controlled for childhood experiences, and ensured that the siblings' upbringing was similar (they found high levels of family dysfunction and abuse in the early lives of both the addicted and non-addicted siblings). Since abuse also causes addiction (we are told), then certainly abuse plus genetic predisposition must equal addiction. Except, then, we still have the one addicted sibling and the one non-addicted one, given the presence of both factors. That's because negative childhood experiences are just as inexact predictors of addiction when actually measured in general populations as is brain structure.

Isn't there any other possible explanation for the differences in siblings' addictiveness? How about the role of purpose, social support, learned skills, etc.? The reason to suggest these things is that another government agency, the Substance Abuse and Mental Health Services Administration (SAMHSA), spent a year surveying leading behavioral mental health professionals in order to uncover the common current elements in people's lives that lead to recovery from mental illness and addiction. SAMSHA identified these psychological and environmental conditions that prevent and dispel addiction: health, home, purpose, and community.

But you can't find those things in a laboratory. And that is why the revolutionary SAMHSA initiative has received virtually no media attention from the likes of Time Healthand. I guess it depends on how you define science: is it the result of work by people wearing white lab coats, or is it identifying the things that make a difference in comprehending and dealing with the world? The factors identified by SAMHSA seem so prosaic. Their only advantage is that they are prosaic, because these are the fiber of human lives, the things parents and people themselves can strive to attain, the things society and social agencies can encourage.

Oh, and these factors actually account for which people resist addiction, and tell us how and why they are able to do so.

If that isn't science, then nothing is.

*One of the most critical -- and best-researched -- areas in psychology is Walter Mischel's work on delay of gratification. People who can't put off experiencing rewards just don't do as well in life. But this trait is strongly influenced by social class. So do the Science results tell us that impulsivity and inability to delay gratification are biologically based differences that account for why people occupy the lower rungs of our society?

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