Wednesday, January 2, 2013

Neuroethics Journal Club: Hooked on Vaccines

Imagine a vaccine that causes our immune system to create antibodies against a drug like cocaine. After being vaccinated, we could snort cocaine and the antibodies would sequester the drug before it could reach our brain. A recent article in Nature Immunology’s Commentary section, “Immune to Addiction”, considers the ethical implications of such vaccines. We discussed the article at December's meeting of the Neuroethics Journal Club, led by Emory Neuroscience graduate student, Jordan Kohn.


Jordan Kohn: his provocative Powerpoint for journal club momentarily made me think I was an anti-vaxxer
Here's what I took away from this month's meeting: we need to integrate the different ways we study addiction. You might wonder what the ways we study substance abuse have to do with a vaccine against it. As the authors of the article say, "How substance dependence is characterized and classified informs the appropriateness of strategies aimed" at preventing or treating it. In other words, we can’t make clear ethical decisions about how to deal with substance abuse until we agree on what it is.

I know I'm not an expert on addiction, but it seems to me that even the experts don't agree on the definition of what they're studying. That’s why I think addiction researchers need to do even more than they’re doing now to relate brain and behavior. I might be saying something that's obvious to people in the field, but the discussion at the journal club made me think what I'm going to say here isn't obvious to everyone. So I'm putting my ideas about how we can further our understanding of addiction into blog post form. Hopefully, it will help continue the discussion.

This image, from the internet, succinctly conveys why I'm worried about how the debate on addiction vaccines may play out

The authors of the commentary talk about how addiction used to be seen as a failure of willpower. Some say neuroscience has replaced this view with the concept of addiction as a "brain disease." Jordan pointed this out as he introduced the paper. Addiction can also be defined in terms of behavior, as he then made a point of telling us. To hammer home the idea of addiction as behavior, Jordan showed us a clip of physician Gabor Maté speaking at a TED conference. Maté puts addiction in a social context. He pointedly states that "if you want to ask the question of why people are in pain, you can't look at their genetics. You have to look at their lives." Similarly, some neuroethicists have argued that calling addiction a "brain disease" ignores the social components of this pattern of behavior[1] and could increase the stigma faced by people suffering from addiction[2].

Yes, addiction can be described as a behavior. Dr. Steven Hyman begins a 2007 review[3] on addiction by stating that it is "defined as compulsive drug use despite negative consequences." Note this definition does not mention the brain. Yet Hyman is a molecular biologist who has spent his career relating genes to behavior, and he continues to lobby heavily for this approach to understanding psychiatric disorders (as described in previous posts on this blog).

We stopped thinking of the brain as a black box that gives rise to behavior a long time ago. If I want proof of this, I don’t have to look further than the work of Emory's Dr. Mike Kuhar, who I couldn't help noticing among the people attendance at this month's journal club meeting. Kuhar, as a young scientist in Sol Snyder's lab, helped provide some of the first evidence that receptors in the brain are real and that they bind drugs like cocaine. If I was blind to the fact that Jordan Kohn and Mike Kuhar are both complicated human beings, I’d be tempted to write up this journal club meeting as if they were the living embodiments of these opposing viewpoints: one view of addiction as a behavior, and another view of addiction as a brain disease.
This is drugs on your brain: Kuhar helped demonstrate where receptors in the brain are located that bind both signalling molecules and drugs like morphine that mimic those molecules' shapes
What we really need to do is embrace both viewpoints. Yes, there's a ton of studies providing evidence that drugs have long-term dramatic effects on reward systems in the brain. Our brains are not perfectly designed. It's easy for chemicals to come along and hijack the reward system. This explains why I have spent enough on coffee to fund the founding a few fincas full of those beany bushes in Brazil. However, the things that happen in my brain when I crave coffee are not exactly what happens in a rat’s brain when he has nothing better to do but press a lever in a cage the size of a shoebox so that a machine injects another bolus of cocaine into his cerebral ventricles. Suddenly studies of other animals that are social drinkers [4,5] don’t seem so ridiculous. (Most studies of alcoholism, for example, use rats or mice, species that live as loners in the wild and often don’t drink alcohol unless sugar is added.) To their credit, some addiction researchers have realized for decades that social environment does play a role in susceptibility to alcoholism and other forms of substance abuse[6]. While we can learn from animal studies, we also need to take a more holistic view of humans, including their environment. There’s only so much that animal models and clinical studies can tell us much about why our society drives people to put certain chemicals in their brains. By the same token, we need to realize there's more to an addict's brain than the reward system, and recovering addicts surely leverage those other brain regions to their advantage.

I realize I'm not the first person to argue that we need to change how we talk about addiction (see for example the article from Buchman, Illes, and Reiner I cited above). As Dr.Kuhar pointed out during the discussion at journal club, it might help to say "addiction" when we're talking about the behavior, and "chemical dependence" when we're talking about changes in the brain. However I want to emphasize that changing people's perceptions of addiction does not change what the science is telling us (although a well-designed experiment might disprove what we think we know). People suffering from many types of "brain diseases" face stigma, but the stigma is a problem in other peoples' brains. It worries me that a focus on the social aspects of substance abuse might make us forget what we've learned in the lab. Let's not set up a false dichotomy between brain and behavior, when most people now concede that the former is responsible for the latter, even when we're not sure who to hold responsible for our brains. At the same time, we need to understand why a brain placed in a certain environment will tend towards a certain behavior, such as addiction. Only then can we have a clear discussion about when we should give up our dependence on some substance that alters our brain chemistry, so we can instead be hooked on vaccines.


Want to cite this post?

Nicholson, D. (2013). Neuroethics Journal Club: Hooked on Vaccines. The Neuroethics Blog. Retrieved on
from http://www.theneuroethicsblog.com/2013/01/neuroethics-journal-club-hooked-on.html

[1] Buchman, Daniel Z., Wayne Skinner, and Judy Illes. "Negotiating the relationship between addiction, ethics, and brain science." AJOB neuroscience 1.1 (2010): 36-45.

[2] Buchman, Daniel Z., Judy Illes, and Peter B. Reiner. "The paradox of addiction neuroscience." Neuroethics 4.2 (2011): 65-77.

[3] Hyman, S. E. (2005). Addiction: A Disease of Learning and Memory. Am J Psychiatry, 162(8), 1414-1422.

[4] Anacker, Allison MJ, et al. "Prairie voles as a novel model of socially facilitated excessive drinking." Addiction biology 16.1 (2010): 92-107.

[5] Anacker, Allison MJ, Jennifer M. Loftis, and Andrey E. Ryabinin. "Alcohol intake in prairie voles is influenced by the drinking level of a peer." Alcoholism: Clinical and Experimental Research 35.10 (2011): 1884-1890.

[6] Spear, Linda P. "The adolescent brain and age-related behavioral manifestations." Neuroscience & Biobehavioral Reviews 24.4 (2000): 417-463.

3 comments:

James Burkett said...

While I wasn't able to attend this journal club, I did note on reading the article that the ethical issues surrounding vaccines for drugs of abuse rests almost entirely on the question highlighted in this article: is addiction a disease? If so, then questions about vaccines for abused substances become questions for which our society has long agreed upon the answers. "Should vaccines be used to control addictive behavior" becomes "should vaccines be used to control disease?" "Is immunity to disease an enhancement or a treatment?" "Who should be vaccinated against disease?" And though some might say substance abusers pose a unique public risk, those who are potential carriers of disease are also a public risk, and we have socially agreed-upon answers to those problems also.

As David highlights, the real question is whether addiction is really a brain disease or not. If we truly accept addiction as a disease, then the ethics of vaccination become clear.

Katherine Bryant said...

"Let's not set up a false dichotomy between brain and behavior, when most people now concede that the former is responsible for the latter" - hear, hear. We can't isolate one from the other, because they are embedded in each other. Just as we've moved on from a strict interpretation of the Central Dogma - as it turns out that gene products can turn around and modify gene expression - so shouldn't we remember that brains may control behavior, but behaviors also impact the brain.

David Nicholson said...

@James: so do you think addiction is a brain disease? Is there a difference between addiction (the behavior) and chemical dependence?

@K-Bry: "...behaviors also impact the brain"--exactly.