Is addiction a disease?

From Our Neurons to Yours Wu Tsai Neuro Podcast

What makes addiction a disease?

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What makes addiction a disease?

I think we all know at this point that addiction is another major epidemic that is sweeping our country and the world, but there are few topics that are more misunderstood than addiction. In fact, some people question whether addiction is even truly a disease.

To  delve into this question of why neuroscientists and health policy experts do think of addiction as a disease, we spoke with   Keith Humphreys, the Esther Ting Memorial Professor of Psychiatry and Behavioral Sciences at Stanford, who is a leading expert on the addiction epidemic.

Humphreys chairs the Stanford Lancet Commission on the North American Opioid Crisis, and has served as Senior Policy Advisor, White House Office of National Drug Control Policy among other prominent policy roles.

Humphreys is also  leader of the NeuroChoice Initiative, a project of the Wu Tsai Neurosciences Initiative dedicated to understanding decision making — from brain circuits to individual choice to group tendencies — with a particular focus on the science of addiction and how neuroscience can contribute to addiction policy.


Stanford Network on Addiction Policy

Stanford Lancet Commission on the North American Opioid Crisis

The NeuroChoice Initiative

Further Reading

Social aversion during opioid withdrawal reflects blocked serotonin cues, mouse study finds

Brain imaging links stimulant-use relapse to distinct nerve pathway

Stanford-Lancet report calls for sweeping reforms to mitigate opioid crisis

Episode Credits

This episode was produced by Michael Osborne, with production assistance by Morgan Honaker and Christian Haigis, and hosted by Nicholas Weiler. Cover art by Aimee Garza.

Episode Transcript

Nicholas Weiler:

This is from Our Neurons to Yours, a podcast from the Wu Tsai Neurosciences Institute at Stanford University. On this show, we crisscross scientific disciplines to bring you to the frontiers of brain science. I'm your host, Nicholas Weiler. 

Here's the sound we created to introduce today's topic, addiction.

What makes addiction a disease? I think we all know at this point that addiction is another major epidemic that is sweeping our country and the world, but there are few topics that are more misunderstood than addiction. In fact, many people question whether addiction is even truly a disease. To really delve into this question of why we do think of addiction as a disease, I spoke to Dr. Keith Humphreys, a Professor of Psychiatry at Stanford University, and a leading commentator on the addiction epidemic.

Keith Humphreys:

My name is Keith Humphreys. I study addiction and the translation of science into public policy. In the last five years or so, I've been fortunate to be one of the leaders of a Wu Tsai Big Ideas Grant, along with Rob Malenka and Brian Knutson, focused on the neuroscience of addiction.

Nicholas Weiler:

I'm going to start with the basic question which is, is addiction a disease?

Keith Humphreys:

Debates about whether addiction is a disease often turn on what people think a disease is. I think of it definitely as a disease or, if you prefer, you can use the word disorder. Now, some people will immediately say, when you point that out that, "Hey, wait a minute, there's behavior involved. That's not a disease, that's just a bad decision." But that doesn't rule out disease. I mean, you can have lung cancer from smoking, you can have cancers from your diet. You can stay out in the sun too long and get melanoma, and yet we say all those things are diseases. The fact that the only way to get addiction is by engaging in certain behavior doesn't change the fact that it's still a legitimate chronic disorder that we should approach as a health problem.

Nicholas Weiler:

And is this something that most people agree on?

Keith Humphreys:

It's interesting. I mean, when people argue about whether an addiction's a disease they're usually arguing about something else. So you'll say it's a disease and then they'll say something like, "But my dad ruined my childhood," or, "My wife ruined our marriage." And so, what they mean is you're telling me I can't be mad at someone who's hurt me. That's not true at all. We can be mad at people who disappoint us or people who hurt us and there are multiple diseases where that happens. People get mad when their mate gets Alzheimer's and not because they don't love their mate but because it's frustrating and they lose memories and there's a lot of hurt and things like that. The other thing is they're arguing about responsibility and they're saying something like, "Oh, you're saying this person didn't do anything to bring this about," or that they deserve a blank check for everything they do.

For me, those things are entirely unrelated to whether or not something is a disease. I can feel sympathy for people who've made bad decisions. We can still feel for them and just because someone's addicted doesn't mean everything they do is okay. Some person was addicted and let's say they robbed somebody or they drove their car and they killed somebody. They're still responsible for those things. They have a problem and they did something wrong and that there can still be accountability despite the fact that they have a disease, which we recognize with many other places where people have diminished capacity, doesn't mean they have zero responsibility.

Nicholas Weiler:

When we talk about it as a disease, is it something that you can see in the brain? Is it something that is changing people's brains?

Keith Humphreys:

That is a very good question. We're certainly not at the level with addiction like we are with, say, a brain tumor where you can do a scan and say, "That's it, that's the tumor right there." Addiction involves the changes in multiple circuits. We've done work here at Stanford where you take people who are addicted to, say, methamphetamine and you show them a picture of methamphetamine and you watch their nucleus accumbens light up like a Christmas tree. And so, we can observe things like that but what we can't do is say, "That signature right there in the brain, I know that person is addicted and this person is not."

If we had that, treatment would be enormously easier because what we have to do now is rely on basically observed behavior and self-report rather than something closer to what you would have in other conditions like a blood test or an x-ray that would tell you the person's well or the person needs more treatment.

Nicholas Weiler:

Why does the brain have this, I don't know, sort of bug that allows it to become addicted to these substances that can kill it?

Keith Humphreys:

You've raised one of the real mysteries of this field. It's partly why it is so frustrating and also so fascinating. How I think about it, I think of it in terms of the evolution of homo sapiens, that if you go back in time to our fore bearers we were not particularly strong, tough. We couldn't fly, we didn't have big teeth, we didn't have body armor. It's that we had a bigger, better brain than our competitors and it got larger and more sophisticated over time and very good at signaling us, using chemicals that everybody knows, to do critical survival things like flee from that tiger and, "Oh, that fruit tasted good. Remember it. Let's come back here again next time we're hungry," and, "This is our newborn, let's love it and take care of it and protect it," all that stuff. Unfortunately, that same system is powerfully activated by the molecules we call drugs.

Although always have been some in nature, there's the opium poppy was growing wild thousands of years ago in the Mediterranean and in Asia, the coca plant in the Andes, but nothing like today where the drugs are far more potent and with modern chemistry we've invented benzodiazepines, and heroin, and morphine, and amphetamines, and methamphetamine, and technologies like the hypodermic needle, which let us use them at higher and higher potencies with more rapid action, which makes them more addictive. And then, global commerce so that if you had a particular taste for cocaine it would not have mattered through 99% of human history unless you happen to live in the Andes, but now, of course, cocaine is a global commodity. All that together means this weakness in our design which did not matter much suddenly matters a whole lot, to the point that about one in six deaths on this planet is attributable to the use of a substance.

Tobacco alone is like 8 million people a year, alcohol's not far behind it, and then you have the illicit drugs killing about 600,000 people a year, which is an extraordinary amount of mortality. If those had all been available 100,000 years ago, homo sapiens might not have come out so well so that's our dilemma. And then, one last thing is that people are sensitive to the amount of effort it takes to acquire different rewards, so the application of taxation or the application of regulations, you can't just walk up to your doctor and get an Oxycontin without a prescription, for example. There's a big tax on cigarettes in California. Those things do, in fact, make people seek alternative rewards so those are good public policies that we should have more of.

Funny thing to me about neuroscience is, it shows how much the brain matters in addiction and at the same time makes you really interested in the environment because it's a lot easier to raise the taxes on cigarettes and immediately affect every brain in California than going around brain by brain trying to figure out some individual level intervention so some people dislike neuroscience interdiction. They say, "Oh, you're taking the attention away from the population public health." I say, "No, actually it makes me more interested in population public health now that I understand the neuroscience.

Nicholas Weiler:

And then, I think, going back to the original question of addiction being a disease, how does your perspective on whether addiction is a disease or addiction is, as I think some people maybe reflexively feel a bad choice, how does that help us get to resolution or a change that can get us out of this terrible epidemic?

Keith Humphreys:

Yeah, it helps you get a certain amount of compassion when you recognize that everybody makes bad behavioral choices. I mean, half of Americans are overweight and yet we have a certain amount of mercy. It's like we're all pretty frail, we're all, in my view, sort of fundamentally flawed. We do the best we can. We can be disappointed in ourselves and others when they engage in bad behavior but still say but we're still going to show some compassion to you. The other part that recognizing it as an illness is, it gets us out of doing something that is stupid and mean and doesn't work and costs a lot of money, which is trying to punish addiction out of people. It was not that long ago when, for addiction to heroin people were put in a prison for years, and still in some parts of the world people are sent off to brutal work camps to just sort of knock the stuffing out of them.

Doesn't work, kills some people, costs a lot of money, compromises liberty. If you accept that it's an illness, it opens up much more therapeutic options that work a lot better, cost a lot less, and do not compromise liberty in a way that's offensive to most people who live in free societies. That's something you get out of taking the risk to think about this as a health problem rather than a crime.

Nicholas Weiler:

All right. Well, thank you so much for talking with me and for helping us answer this question about what addiction really is.

Keith Humphreys:

Thanks very much for asking, I really enjoyed the conversation.

Nicholas Weiler:

Thanks so much again to our guest, Keith Humphreys. 

To learn more, check out the Wu Tsai Neurosciences Institute at 

For more info about our guest's work, check out the links in the show notes. 

This episode was produced by Michael Osborne with production assistance by Morgan Honaker and Christian Haigus. I'm your host, Nicholas Weiler.