Wednesday, June 23, 2010

The Disease Model Reconsidered

Historian looks at resistance to the “NIDA paradigm.”

The history of addiction as a brain disease “looks a lot like the history of atoms or germs, insofar as these were older and controversial ideas for which scientific confirmation later became available,” writes historian David Courtwright, author of Forces of Habit: Drugs and the Making of the Modern World.

In a recent issue of the social science journal BioSocieties, Courtwright surveys the history of the disease paradigm of drug addiction, and, in doing so, brings into focus several key dilemmas related to what former National Institute on Drug Abuse (NIDA) director Alan Leshner once characterized as the “quintessential biobehavioral disorder.”

The scientific evidence available to us at present largely supports a statement like Leshner’s. Researchers have documented long-term changes in brain structure and function due to drug abuse, and neuroimaging technologies have resulted in maps of the abnormal neuronal activity addicts exhibit. Courtwright cites the discovery of the endogenous opioid system, the mapping of receptor pathways, and the growing understanding of the mesolimbic dopamine reward pathway as evidence of clinical confirmation of theories about addictive disease that has been floating around in one form or another for many years.

Why then, Courtwright asks, does the medical profession largely stay clear of issues having to do with our law enforcement-driven drug war? Why are clinical professionals not on the front lines of revolt over this issue? “If addiction was beyond the individual’s control, then criminal punishment was as inappropriate as jailing a schizophrenic who wandered into an emergency room,” the author writes.

The most obvious reason for this conundrum, says Courtwright, is that “the brain disease model has so far failed to yield much practical therapeutic value.” The disease paradigm has not greatly increased the amount of “actionable etiology” available to medical and public health practitioners. “Clinicians have acquired some drugs, such as Wellbutrin and Chantix for smokers, Campral for alcoholics or buprenorphine for heroin addicts, but no magic bullets.” Physicians and health workers are “stuck in therapeutic limbo,” Courtwright believes. “The drug-abuse field is characterized by, at best, incomplete and contested medicalization.”

Moreover, unlike the current situation in the case of, say, diabetes or schizophrenia, “at least four important groups continue to wrestle for control of the addiction field.” (Medical personnel, police, social scientists, and political officials.) Social scientists, in particular, are frequently skeptical about the NIDA disease paradigm “as part of a broader post-World War II pattern of resistance against biological explanations of behavior, genetic research and the neo-Darwinian renaissance.”

Social scientists and neuroscientists “still live in their own gated academic communities,” Courtwright alleges. “There is a lot more at stake in the brain disease debate than our understanding of addiction.”

However, these problems do not mean that valuable findings in one area--addictive disease theory--cannot produce innovations in other research fields as well. In fact, such spinoffs happen all the time. Courtwright points to advancements in our understanding of evolution: “Michael Kuhar has argued that, because the brain co-evolved with neurotransmitters, it can usually manage its internal chemistry quite well. But it did not co-evolve with drugs, understood as recently introduced and wholly exogenous super-neurotransmitters that can override the brain’s control mechanisms.”

The author also cites spinoffs in economic studies: “The permanent alteration of neurons and the development of addiction in some, but not all, users also helped explain the commercial and tax appeal of drugs, insofar as they were nondurable goods with relatively inflexible demand curves. Even non-addicted users tended to consume more over time, because of tolerance.”

In the end, it is just possible to contemplate some sort of fusion, or meeting of the minds, over the disease model. As Courtwright speculates, “it may turn out that the tension between the personality and brain disease models is more apparent than real.” He cites as evidence such connections as the fit between impulsive, thrill-seeking behavior and an associated paucity of dopamine D2 and D3 receptors in the midbrain region. The result? Such people “have less inhibition of dopamine, and experience more reward when stimulated by risky behavior.” A nice fit. And the number of nice fits between social science and brain science continues to accumulate.

“If the brain disease model ever yields a pharmacotherapy that curbs craving, or a vaccine that blocks drug euphoria, as some researchers hope,” Courtwright says, “we should expect the rapid medicalization of the field. Under those dramatically cost-effective circumstances, politicians and police would be more willing to surrender authority to physicians.”


Anonymous said...

Is it the position of the author that no benefit ever comes from drug use? This seems judgemental and naive.
Speaking of the blocking of euphoria from drugs in such matter of fact terms is a concern, it seems to have parallels with female circumcision (so they get no pleasure from sex).
Humans have always used drugs, always will and to look only at neurochemicals rather than the harm done by the laws which attempt to deny reality seems misguided. I would further argue that abuse and inequality in societies are the driving forces behind problematic use.

dirkh said...

I think the author is saying that no benefit ever comes from denying the solid fact that some people who use drugs will end up clinically addicted to them. He's not addressing the overall issue of drug use, except to point out the good drug/evil drug dichotomy that helps confuse things in the medical marketplace.

I don't see drugs to block highs or blunt cravings for addicts as any kind of slippery slope leading to pleasure-denying pills or procedures for the population at large.

Anonymous said...

I think Courtwright is conflating addictive or problematic drug use with drug use in general.

The statement that 'the brain did not co-evolve with drugs' is odd: plants have been producing ever more sophisticated drugs for over 300 million years, and drug use by animals long predates humanity.

Drug use can be normative and beneficial as well as pathological, and unless this is explicitly recognised there is most certainly a slippery slope to invasive procedures for the population at large.

TGGP said...

“If addiction was beyond the individual’s control, then criminal punishment was as inappropriate as jailing a schizophrenic who wandered into an emergency room,”
As we've discussed before, this is wrong. Addicts respond to incentives if they are swift & certain. The track record of incentivization is far better than that of disease-model treatment.

Anonymous said...

Anonymous you doth protest too much. No healthy, social user gets that defensive.

Humans have used drugs for a long time, but we have not evolved to use them in the social conditions that exist today:

Adi Jaffe said...

Quite the discussion.
It's upsetting to me that the fact that many people can, and do, use drugs recreationally gets somehow introduced into every discussion about those who cannot and become compulsive about their use. For the former, I agree that restrictions are somewhat misguided, but there's no doubt that it's the latter group that is most affected by those laws.
The suggestion that entire populations will possibly be forced to take part in procedures that will block their drug-reward mechanisms is quite far-fetched. Gattaca was a nice movie, but come on now (I know it had to do with genes, not pharmacological interventions, but the analogy seemed to work).
TGGP, I couldn't possibly look through those links (too much work and the 2nd one seemed unrelated), but with recidivism rates above 70%, it's hard to make the case the incentives work better than other interventions. As usual, I think combinations work far better than anything does alone, and incentives in treatment (in the form of Contingency Management or CM) have been shown quite effective at keeping people in treatment longer. That being said, they've improved retention but not necessarily long term outcomes, so there you have it. And when you say "disease model treatment" are you referring to everything from pharmacotherapies to 12-step work, CBT, and psychotherapy? If you are, again, I think the evidence is pretty clear that they all work for a small portion of those involved. I'll put in my 2 cents again: "Combinations."

TGGP said...

Recidivism rates were far below 70% for Hawaii's "H.O.P.E" program. I believe Mao achieved similarly low rates through more brute-force methods.

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