In 'Dopamine Nation,' Overabundance Keeps Us Craving More

TERRY GROSS, HOST:

This is FRESH AIR. I'm Terry Gross. We're going to talk about the interconnection of pleasure and pain and how that connection helps explain addiction - not just addiction to alcohol and drugs like opioids, but addictions to food, sex, gambling and social media. My guest, Dr. Anna Lembke, is the author of the new book "Dopamine Nation." Dopamine is the neurotransmitter, the chemical messenger, most involved in processing rewards. The more dopamine a drug or behavior releases, the more addictive it probably is.

Dr. Lembke is a psychiatrist who's the medical director of addiction medicine at Stanford University and chief of the Stanford Addiction Medicine Dual Diagnosis Clinic. The clinic is for patients who have a mental health disorder, like depression or bipolar syndrome, as well as a drug or alcohol addiction. She's also the author of the 2016 book "Drug Dealer M.D.," about how opioids were marketed to doctors to prescribe for their patients, which helped lead to the opioid epidemic.

Dr. Anna Lembke, welcome back to Fresh Air. Let's start with the basics. What is dopamine?

ANNA LEMBKE: So dopamine is a neurotransmitter that sends signals from one neuron to another, and it's probably the most important neurotransmitter in our experience of pleasure, motivation and reward.

GROSS: So this is all stuff that's going on in the brain.

LEMBKE: Yes, it's going on in the brain. Exactly.

GROSS: So what role does dopamine play in addiction?

LEMBKE: Well, dopamine is the final common pathway for all pleasurable, intoxicating, rewarding experiences. So different drugs and behaviors work on different endogenous or innate systems. There's the opioid system. There's the cannabinoid system. There's the adrenaline system. But ultimately, the final common pathway of all of those rewarding substances and experiences is dopamine.

GROSS: You write that the more dopamine any experience or substance releases, the more addictive it means that experience or substance is. So are scientists measuring dopamine release now to figure out what the most addictive drugs are or experiences?

LEMBKE: So that experiment has been done in rats, for example, putting a probe in their brain, measuring the amount of dopamine released in response to different types of substances. Now, remember, we all have a baseline release of dopamine that's sort of always there. And then when we ingest certain substances or engage in certain behaviors, our dopamine either goes up or down in response to that substance or behavior. So, for example, chocolate increases dopamine above baseline about 50%. Sex is about 100%. Nicotine is about 150%. And amphetamines is about 1,000%.

GROSS: Whoa.

LEMBKE: Yeah.

(LAUGHTER)

GROSS: And that explains why amphetamine is more addictive than chocolates or sex.

LEMBKE: Well, yes and no. I mean, one of the reasons that amphetamine causes dopamine to be released at such a high level initially is because the actual mechanism of amphetamine is to directly release dopamine in the synapse, whereas, for example, alcohol works through our endogenous opioid system. And so dopamine is more of a downstream result of alcohol ingestion. The other thing to keep in mind is that there's this whole concept of drug of choice. And what might be pleasurable and rewarding for you might not be pleasurable and rewarding for me. So in addition to the common pathways that all substances exert on our brain, we also have our interindividual differences.

GROSS: Let's talk about the interconnection of pleasure and pain. Pleasure and pain responses are located in overlapping parts of the brain. Can you describe the, like, physiological overlap of pleasure and pain in the brain?

LEMBKE: Sure. So to me, one of the most fascinating findings in neuroscience in the last 75 years is that the same areas of the brain that process pleasure also process pain and that pleasure and pain work like a balance. So if you imagine that in your brain, there's a teeter-totter, like something you would find in a kid's playground - and when that teeter totter is at its resting baseline, it's level with the ground. When we do something that's pleasurable, for example, when I eat a piece of chocolate, then my pleasure-pain balance tilts just a little bit to the side of pleasure, and I experience release of dopamine in my brain's reward pathway. But one of the governing principles regulating this balance is that it wants to remain level, which is what neuroscientists call homeostasis. It doesn't want to be deviated for very long, either to the side of pleasure or pain - so that when I eat a piece of chocolate, immediately, what my brain will do is adapt to the presence of that pleasurable stimulus by tipping my balance in equal and opposite amount to the side of pain. And that's the after effects or the comedown or, in my case, that moment of wanting a second piece of chocolate. Now, if I wait long enough, that feeling passes, and homeostasis is restored.

GROSS: So describe the pain after the pleasure. Is it like I'm disappointed that this experience of eating the chocolate is now over? Or is it more like craving? I want more. I want more of it. I want more of that pleasure. And not having that pleasure - it's increasing my sense of pain.

LEMBKE: Yeah, great question. So it's really both, right? So when that pleasure-pain balance tilts to the side of pain after the experience of pleasure, that pain is subjectively experienced as a number of different things. One of it is just like a subjective feeling of being uncomfortable, restless, irritable, unhappy and wanting to recreate the feeling of pleasure. But that's also, in many ways, what craving is, right? So not wanting to have the pleasure again, being preoccupied with eliminating the experience of pain that we feel in the aftermath. And I will say, too, it's very reflexive. It's not like I'm even consciously aware of that aftereffect or the come down. It can be very subtle, but I'm just sort of aware of, hmm, wanting to have another piece of chocolate.

GROSS: With repeated exposure to the same pleasure or a similar pleasure, whether it's an experience or if it's chocolate or if it's a drug, you keep wanting more of it. So why - what's going on? Why do you keep wanting more? Why does it take more and more to keep you satisfied?

LEMBKE: So the way that I think about it or visualize it in my brain is that after I have a pleasurable experience - like, I have a piece of chocolate - then these little gremlins hop on the pain side of my balance to bring the balance level again. But the gremlins really like it on the balance. So they don't get off. Again, they stay on until my balance is tipped an equal and opposite amount to the side of pain. And again, that's the aftereffect or the hangover or the comedown. Now, with waiting, the gremlins hop off, and balance is restored, but the gremlins never entirely go away. They're sort of left in our brain. They're the neuroadaptation gremlins, which means that if I do eat a second piece of chocolate, my gremlins are ready to go, right? I Don't need to create them. They hop right on the balance. And in fact, they tip that balance harder and longer to the side of pain. So what that means is, with repeated exposure to any pleasurable experience, the initial stimulus of pleasure gets weaker and shorter, and the aftereffect of pain gets stronger and longer, which means that over time, I need more and more of the initial stimulus to get the same effect. And this is what's called tolerance, needing more of the drug to get the same effect or finding that over time, the same dose of the drug has less of an impact.

GROSS: So you keep needing more and more, and that explains why people can get addicted to food and can sometimes overeat. It explains, I guess, sex addiction and certainly - does that explain - well, actually, does that explain drug addiction, too? Is there more going on in drug addiction than there is to, say, eating chocolate 'cause the drugs - certain drugs also have, I think, more physiological, addictive qualities - more chemical, I should say, addictive qualities?

LEMBKE: You know, this phenomenon really pertains to all rewarding experiences. And what happens over time, and which is essentially the fundamental process that leads to addiction, is that if I continue to consume a dopamine-releasing, high-reward drug or behavior, that after a while, in order to try to reassert homeostasis, I develop so many gremlins on the pain side of my balance that they fill the entire room, which means that when I'm not using my drug, I'm essentially miserable, right? I'm in a dopamine deficit state. I have a pleasure-pain balance that's tilted to the side of pain. And now I need to use my drug not to feel good but just to restore a level balance, just to feel normal. And when I'm not using my drug, I experience the universal symptoms of withdrawal - irritability, anxiety, insomnia, dysphoria and mental preoccupation with using my drug, which we call craving.

So the important message here is that when people become addicted - when we become addicted, we essentially change our brains and reset our threshold for experiencing pleasure and pain, such that it's harder to experience pleasure and easier to experience pain because we have a pleasure-pain balance tilted to the side of pain.

GROSS: So that's the central paradox of your book, is that the pursuit of pleasure can actually lead to pain.

LEMBKE: That's exactly right. That hedonism ultimately leads to anhedonia or lack of joy.

GROSS: Let's take a short break here. If you're just joining us, my guest is Dr. Anna Lembke, author of the new book "Dopamine Nation: Finding Balance In The Age Of Indulgence." We'll be right back. This is FRESH AIR.

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GROSS: This is FRESH AIR. Let's get back to my interview with Dr. Anna Lembke, author of the new book "Dopamine Nation." It's about the neurochemistry that explains the connection between pleasure and pain and how that applies to addiction. She's the medical director of addiction medicine at Stanford University.

Getting back to the difference between an addictive drug that has a chemical basis versus an addictive experience, like, what's the difference, in terms of what's going on in your brain and the difficulty of breaking that addiction?

LEMBKE: The difference is that addictive drugs don't require as much learning. I mean, there's lots of learning that goes around with obtaining and using the drug and anticipating the rewards and recovering from the rewards, but the chemical itself is sort of like a shortcut to all of those experiences, whereas behaviors, like gambling or sex, don't work by this chemical mechanism initially, although there is a strong chemical reaction in the brain to those behaviors that ultimately makes behavioral addictions look exactly like drug addictions. So I'm not sure, at the end of the day, there is that much difference between getting addicted to a drug and getting addicted to a behavior.

And certainly in my clinical work, the patients that I see who are addicted to gambling, who are addicted to video games, who are addicted to pornography - their story is exactly the same as people who get addicted to cannabis or heroin or nicotine. They start out using the drug in order to feel good or in order to experience less pain, that is to say, solve a problem that they're having in their lives. And over time, with repeated exposure, that drug works less and less well, but they find themselves unable to stop because when they're not using, then they're in a state of a dopamine deficit. They're experiencing pain and craving and compulsions to use.

GROSS: When you're using an addictive drug, it's often recommended that you titrate down, that instead of just, like, going cold turkey, that you keep lowering the dose so that your body learns to tolerate less and less over time. Do you find that useful with patients that you have who are addicted to, say, social media or sex?

LEMBKE: So there are some drugs that if you have become addicted to them and you stop abruptly, you can go into life-threatening withdrawal, and those would include alcohol for some individuals - if they stop abruptly, they can experience life-threatening alcohol withdrawal - also, anti-anxiety medications like benzodiazepines, which includes drugs like Valium and Xanax. If people have become physiologically dependent and addicted to those drugs and they stop them abruptly, they can experience life-threatening withdrawal. And in some cases, opioids can also lead to life-threatening withdrawal.

So in those situations, we often recommend a slow taper, as opposed to abrupt discontinuation. But with other types of drugs and with behavioral addictions, the very first intervention is actually abstinence. So, you know, what I recommend and what we do in our clinic is typically to recommend a period of four weeks of abstinence from that drug. We ask patients to quit, to choose a specific quit date, to kind of wrap their head around that quit date, to implement, you know, resources to help them with that quit date. And then we ask them to stop on that quit date. And that would include everything from, you know, vaping cannabis to smoking cigarettes to being addicted to your smartphone.

GROSS: People very loosely say, oh, I'm addicted to my cell phone. I'm addicted to social media. And they don't literally mean they're addicted to it, but do you think people literally do get addicted to cell phones and social media?

LEMBKE: I do think that people literally get addicted to cell phones and social media, yes. It's important to recognize that addiction is a spectrum disorder, and it is possible to be a little bit addicted. Also, the same brain mechanisms that mediate severe addiction also mediate our minor addictions. So we're all evolutionarily designed to approach pleasure and avoid pain. And that kind of neurobiological wiring is exactly what has kept us alive for millennia. And it's also the very same wiring that makes us all vulnerable to addiction. So I don't think that anybody is immune from this problem. And I do believe that smartphones are addictive. They've been engineered to be addictive and that doesn't really - you know, we don't really need more studies to show that that's true. All you need to do is go outside and look around.

GROSS: Dr. Lembke, you write that the brain was not designed to live in a world of overabundance. And in some countries, like the U.S., in some socioeconomic classes, people do have overabundance in their lives - easy access to foods, too many varieties of foods, too many things to read, movies to watch, drugs to take, experiences to have. Why isn't our brain adapted to that? Why is this overabundance a problem that can lead to pain and addiction?

LEMBKE: The mechanisms in our brain that compel us to approach pleasure and avoid pain were evolved over millions of years for a world of scarcity. And in a world of scarcity, in order for us to stay alive, we have to be extremely motivated to go out and seek food, clothing and shelter. The problem is, in today's modern ecosystem, those things are all provided. We don't even have to get up off the couch in order to have them come to us. And our brains were really not wired for that. And as a result, I think living in this modern age is very challenging but for different reasons. We're now having to cope with, how do I live in a world in which everything is provided, and if I consume too much of it, which my reflexes compel me to do, I'm going to be even more unhappy? That's really what "Dopamine Nation" is about, trying to figure out how to live in that world and holding up people in recovery from addiction as modern-day prophets for how to do that.

GROSS: But you write things like trauma, social upheaval and poverty contribute to the risk of becoming addicted. So explain that aspect of it.

LEMBKE: So there are many risk factors for addiction. They include things like past history of trauma, co-occurring mental illness, poverty, unemployment. All of those things increase our risk for becoming addicted. But one of the most important risk factors, which is often ignored and I think is most relevant today, is simple access. If you live in a neighborhood where drugs are sold on a street corner, you're more likely to try them, and you're more likely to get addicted to them.

GROSS: So what do you think the implications here are for the criminal justice system? If poverty leads more easily to addiction because of scarcity and - of many things but easy access to potent drugs - you know, if that's true, and then the consequences for that are jail, prison, like, what does that say about how we're dealing with poverty in the criminal justice system?

LEMBKE: It's very clear that imprisoning people with addiction is not the solution. I mean, that's - we've - I think it's fair to say that that is not going to be the way that we are going to help people who develop this problem of over - of compulsive overconsumption, especially when people are living in poverty are more vulnerable to the problem of addiction by virtue of living in poverty and not having access to other types of rewards. So because of that, you know, we really need to reform - and it's happening now - the criminal justice system, to help people get access to treatment for addiction rather than imprisoning them for their behaviors related to addiction.

GROSS: Let's take a short break, and then we'll be right back. If you're just joining us, my guest is Dr. Anna Lembke, author of the new book "Dopamine Nation." She's the medical director of addiction medicine at Stanford University and chief of the Stanford Addiction Medicine Dual Diagnosis Clinic. We'll be right back. I'm Terry Gross, and this is FRESH AIR.

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GROSS: This is FRESH AIR. I'm Terry Gross. Let's get back to my interview with Dr. Anna Lembke, author of the new book "Dopamine Nation." It's about the interconnection between pleasure and pain and how that connection helps explain addiction. Dopamine is the neurotransmitter, the chemical messenger, that's most connected with processing, rewarding pleasurable behavior. The more dopamine a drug or behavior releases, the more addictive it is. Dr. Lembke is a psychiatrist who's the medical director of addiction medicine at Stanford University and chief of the Stanford Addiction Medicine Dual Diagnosis Clinic. The clinic is for patients who have a mental health disorder, like depression or bipolar syndrome, as well as a drug or alcohol addiction.

Let's talk a little bit about COVID. Are you seeing new addictions, more addictions because people are in so much psychological and often physical pain because of the pandemic? And many sources of pleasure have been eliminated. People have, you know, been shut in at home for a long time. And just as things started to open up, they started to close down again. So are there certain kinds of addictions you're seeing more of now?

LEMBKE: Certainly, COVID has led to more people spending more time on their screens and with their devices. So that's that's something that I'm seeing. But I think it's important for me to tell you that I've also had a lot of patients who are - who have done better during quarantine. And what they tell me is that the world is kind of a hyperstimulated, triggering place for them. And quarantine forced them to slow down and also eliminated a lot of the types of interactions and stimuli that would typically trigger relapse or reuse for them. So I would say I've seen sort of a bimodal distribution in terms of the COVID response in my patient population. Again, for some people, it's been absolutely terrible. Of course, we've seen an uptick in overdose-related deaths, including some of my own patients. And that's absolutely tragic. And the reason for that is because of the disrupted drug supply but a drug supply that still has a lot of easy access to things like illicit fentanyl, which is highly - a highly lethal opioid.

GROSS: Are there other patterns that you're seeing in how COVID is affecting your patients?

LEMBKE: Well, another pattern is that I'm seeing a quite a few individuals who previously were able to use things like COVID and cannabis and digital media in moderation but then found themselves during quarantine and during Covid slipping into addictive behaviors and so seeking out care for the first time. Another pattern I'm seeing or I saw, especially early in quarantine, is people who have been dealing with addiction for a long time but just didn't have the time or the wherewithal to get help, who used the quarantine and COVID is kind of an opportunity to seek out treatment.

GROSS: You've explained why abstinence is so important in overcoming addiction and that you ask your patients to have, like, four weeks of abstinence 'cause that's what it takes for the brain to undo all the negative balance that was created by the experience or the drug that created the addiction. How do you convince your patients that they'll be happier in the long run if they deal with the pain of abstinence?

LEMBKE: Yeah, so that's really an art in the science that I've had to develop over many years because people come to me in a lot of pain and distress. They're anxious. They're depressed. They can't sleep. They're compulsively consuming substances or behaviors. And they want me to relieve their suffering. And when they come in, what I say to them often is, well, in order to get better, you're going to have to first hurt more. You know, what I'm going to ask you to do is really hard. I'm going to ask you to abstain from these addictive substances and behaviors, which is going to make you feel worse. So it is something that I've had to develop over many years. How do you do that? How do you say to somebody who's suffering, well, OK, my solution for you is to suffer more? But what I do is I just really kind of explain the neurobiology of the brain. I explain the pleasure-pain balance. I explain how consumption of these addictive substances has essentially reset their brain to the side of pain and that, in fact, their suffering may be a result of engaging in these pleasurable activities. It always feels to them like the depression and the anxiety and the insomnia is driving the substance use. But in fact, the substance use may be causing the depression, anxiety and insomnia. And I explain that by, again, explaining the pleasure-pain balance and the neurobiology of the brain. So essentially, what I say to them is, I'm asking you to do an experiment. And I think - so I'm hypothesizing - that your social media use or your cannabis use or your alcohol use is actually making you more depressed and anxious. So I want you to stop using for four weeks. And I warn them that they're going to feel worse before they feel better. I say to them, in the first two weeks, you are going to have more anxiety, more insomnia, more depression. But that's not the anxiety and insomnia and depression that you're going to have to live with. That's withdrawal-mediated anxiety, insomnia and depression. And if you can just get through those first two weeks, I think that by four weeks, you are going to be feeling a whole lot better.

GROSS: Should we insert another warning here that with some drugs, including alcohol, slowly decreasing the amount might be the most advisable thing? And maybe it's best to consult a doctor or a professional before figuring out what your plan is.

LEMBKE: Yeah. There are certain drugs like alcohol or drugs like benzodiazepines, anti-anxiety drugs like Xanax and Valium or drugs like opioids, where you may not want to abruptly stop using them because you could go into a life-threatening withdrawal. And really, for anybody who's listening, you should consult a professional before making these interventions.

GROSS: Let's take another short break here. If you're just joining us, my guest is Dr. Anna Lembke, author of the new book "Dopamine Nation: Finding Balance In The Age Of Indulgence." We'll be right back. This is FRESH AIR.

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GROSS: This is FRESH AIR. Let's get back to my interview with Dr. Anna Lembke, author of the new book "Dopamine Nation." It's about the neurochemistry that explains the connection between pleasure and pain and how that applies to addiction. She's the medical director of addiction medicine at Stanford University.

Is there a difference in how addictive behavior or addictive substances operate in the brains of, say, teenagers as opposed to adults?

LEMBKE: The same basic effects on the brain occur in teenagers as adults, but the difference is that teenagers' brains are still developing. So we are - when we're about 3 years old, we have more neurons in our brain than we're ever going to have for our entire lives. And what happens is from about age 3 to 5 onward is there's a careful pruning process that happens where the neurons that we use less are slowly pared back, literally pruned or clipped. And those neurons that we use more frequently are myelinated. In other words, they're sort of, like, oiled like an engine and made more efficient. And this continues to occur all through the developmental process until about age 25. So what that means is that we are building our neurologic infrastructure to last our lifetime.

So the coping strategies that we learn in our childhood and adolescent years are the ones that get hardwired into the brain. Likewise, substances that we may use or coping behaviors that are maladaptive that we may use also get then deeply embedded into our neurological framework such that potentially it may be that much more difficult later in adulthood to change those behaviors, which is why it's so important to make sure that we protect our kids and try to intervene early when kids are showing signs and symptoms of maladaptive consumption.

GROSS: Can you apply that to children who are growing up during the COVID era?

LEMBKE: Yeah. I mean, I think this is especially relevant for kids growing up in - during COVID and during quarantine because, you know, kids are stuck at home. They've got to do all their school online. They've got limited social contacts. The screen becomes their everything. And, you know, screens are - I mean, we've all, you know, developed attention deficit disorder as a result of our digital devices. And I think teenagers, you know, even more so now, are trying to multitask, are doing everything online, are, you know, constantly interrupting themselves with other digital media. I do worry quite a bit that teenagers today have lost the art of doing anything that doesn't involve immediate gratification and are losing the art of doing anything that requires sustained attention and some degree of boredom. I mean, I think that applies to all of us but I think especially people, you know, who are young and are growing up in this strange world.

GROSS: When you were in medical school, you were taught that mental health disorders had a biological basis and could be treated with drugs to replace whatever chemical was missing. How has your confidence in antidepressants and anti-anxiety medications changed over the years?

LEMBKE: I want to start by saying that I'm so grateful for these tools, antidepressants, antipsychotics, mood stabilizers. I believe that they're lifesaving for some patients. But I'm certain that we're overprescribing these medications. One in 4 adults in the United States takes a psychotropic medication and 1 in 20 children. And that's just not OK. I have seen so many instances of patients cavalierly being put on psychiatric medications that harm them in overt and long-lasting ways but also in more subtle ways. So I think, you know, it's a time of reckoning where we really need to reevaluate the way that we're prescribing these drugs in medicine and to consider not just the potential benefits but also the potential harms.

GROSS: Now, I have another question about dopamine. You know, we've been talking about dopamine as a factor in addictive behavior and addictive chemicals. But dopamine is also an issue with Parkinson's disease. It's a shortage - part of the footprint of the disease is that there's a shortage of dopamine. And Parkinson's has to do with tremors, with stiffness and with other related things. So what's the relationship? Like, why is dopamine an issue there? And that's not about pleasure and pain.

LEMBKE: Right. So, I mean, dopamine, you know, works all over the brain. And the two areas which we understand best are inter-reward pathway, which we've been talking about in relation to addiction. But also, dopamine is integral to movement. And Parkinson's is a movement disorder caused by a decay of dopamine neurons in an area of the brain called the substantia nigra. So as those dopamine neurons in the substantia nigra decay, less dopamine is released in that specific area, and people develop problems with movement such as tremor and stiffness. So those are discrete systems both mediated by dopamine, but they're not entirely unrelated because a movement is inextricably interwoven with reward, right? I mean, in order to go get the thing that is rewarding, we actually have to get up and move toward it. And even the most primitive organisms will demonstrate movement and release dopamine in response to food in their environment. So you know, from an evolutionary perspective, seeking out reward and physical movement are closely related.

GROSS: So is Parkinson's related to depression or to, you know, a lack of pleasure because there's a dopamine shortage? Or is that just in a completely different part of the brain?

LEMBKE: They are related. And people with Parkinson's, as part of their syndrome of Parkinson's, can get severely depressed. The treatment for Parkinson's is often to give L-dopa, which is a synthesized form of dopamine that does cross the blood-brain barrier and then is turned into dopamine in the brain. And there are case reports of people who are given L-dopa for Parkinson's disease who then develop things like gambling addiction. So these things are, you know, are related.

GROSS: Let's talk about some practical suggestions you give your patients about how to end behavioral or chemical addiction. One of the things you emphasize is radical honesty. What do you mean by that?

LEMBKE: Over the years, seeing many wonderful patients in recovery, one of the recurring themes that has stood out to me is how telling the truth, not just about big, important things in their lives, but about everything, is central to their recovery from addiction. And I got really curious about that. I started to wonder, gee, you know, what is that? Why is that - why is it that telling the truth would be so important to stopping these addictive behaviors? And my research led to a lot of fascinating, different discoveries about the role of truth-telling in our lives, not just as a way to limit compulsive overconsumption and addiction, but also just to have better lives, you know, to improve the quality of our relationships with others or with ourselves.

And so one of the things I recommend to my patients in addition to, you know, the initial period of the dopamine fast or the abstinence is, I say to them, you know, in this month, I want you to try really hard not to lie about anything. And by that, I mean, not just don't lie about your substance use or your online behaviors or whatever it is, I want you to try really hard not to lie about anything, why you were late to work, you know, why you had a - I don't know - a second piece of cake or whatever it was. And I warn them that it's really hard because, on average, you know, the average adult tells about one to two lies a day. We all lie. You know, we lie in ways large and small.

And it's really hard to tell the truth. And to tell the truth, you actually have to have, like, an active sort of truth-o-meter going on where you're sort of constantly observing what you're saying and saying to yourself - now, am I telling the truth? Was that really the whole truth and nothing but the truth? But it - I think it has really important brain health properties. And the most important among them is probably that it strengthens the ties between our prefrontal cortex and our limbic brain.

So the prefrontal cortex is that part of our brain just behind our forehead engaged in decision-making, long-range planning, delayed gratification, storytelling. So telling the truth strengthens that part of the brain and, in turn, strengthens the connections between that part of our brain and our reward pathway, which is a much older, more primitive part of our brain. And it thereby helps us really control our reward pathway and control our consumption.

GROSS: Dr. Lembke, it's really been a pleasure to talk with you. Thank you so much.

LEMBKE: You're welcome. Thank you for having me. It's - I'm such a big fan of your show, and it's really an honor to be on.

GROSS: Dr. Anna Lembke is the author of the new book "Dopamine Nation." She's the medical director of addiction medicine at Stanford University. After a break, Maureen Corrigan will review a debut collection of short stories she describes as exceptional. This is FRESH AIR.

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