Chapter 4. The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
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By Gretchen Reynolds We’ve probably all heard someone exclaim, “Ah, my endorphins are kicking in!” at the end of a good run. Endorphins are famous for supposedly producing “runner’s high,” that fleeting sense of calm and euphoria that engulfs many of us after a satisfying workout. But in fact, endorphins may be unfairly hogging the credit for making workouts enjoyable, according to an enlightening new experiment with animals. The findings suggest that endorphins have little to do with runner’s high. Instead, that euphoric feeling may be the product of a completely different but oddly familiar substance — the body’s own endocannabinoids, the chemicals that, like the cannabinoids in marijuana, lighten mood. Endorphins first became a household word in the 1980s, when researchers found that blood levels increased after prolonged exercise. This finding made sense. Exercise can cause discomfort or pain, and endorphins are the body’s self-produced opiates, with pain-relieving properties much like morphine. From that discovery, it was a short step to believing that endorphins must also produce the pleasurable mental sensations that many people feel after exercise. But there is a substantial problem with that idea, and it involves the substantial-ness of endorphins. They are large molecules, too big to pass through the blood-brain barrier. They might staunch pain in the muscles, but they wouldn’t have effects directly inside the brain, where any high would originate. So for the past decade or so, scientists have been looking for other substances that might be involved in making exercisers feel high, which led them, perhaps unsurprisingly, to endocannabinoids. © 2015 The New York Times Company
Keyword: Drug Abuse
Link ID: 21488 - Posted: 10.08.2015
By Jessica Schmerler Many studies trumpet the positive effects of oxytocin. The hormone facilitates bonding, increases trust and promotes altruism. Such findings earned oxytocin its famous nickname, the “love hormone.” But more recent research has shown oxytocin has a darker side, too: it can increase aggression, risk taking and prejudice. A new analysis of this large body of work reveals that oxytocin's effects on our brain and behavior actually look a lot like another substance that can cut both ways: alcohol. As such, the hormone might point to new treatments for addiction. Researchers led by Ian Mitchell, a psychologist at the University of Birmingham in England, conducted the meta-analysis, which reveals that both oxytocin and alcohol reduce fear, anxiety and stress while increasing trust, generosity and altruism. Yet both also increase aggression, risk taking and “in-group” bias—favoring people similar to ourselves at the expense of others, according to the paper published in August in Neuroscience and Biobehavioral Reviews. The scientists posit that these similarities probably exist because oxytocin and alcohol act at different points in the same chemical pathway in the brain. Oxytocin stimulates release of the neurotransmitter GABA, which tends to reduce neural activity. Alcohol binds to GABA receptors and ramps up GABA activity. Oxytocin and alcohol therefore both have the general effect of tamping down brain activity—perhaps explaining why they both lower inhibitions. © 2015 Scientific American
by Bethany Brookshire Last weekend, I ran the Navy-Air Force half-marathon. After pounding pavement for an hour or so, my legs began to feel light. Slightly numb. I felt fantastic. I had to remind myself to run, not to stop and dance, and that singing along to my candy-pop workout music — even at mile 10 — is not socially acceptable. It’s the hope of this euphoria — this runner’s high — that keeps me running. We’re not totally sure what’s responsible for this incredible high. Some studies call out our body’s endorphins. Others point to cannabinoids — chemicals related to the active compound in marijuana. A new study suggests that the appetite hormone leptin may play a role in getting us going. And from an evolutionary perspective, it makes good sense. When our dinner might make a quick getaway, it’s important to link our drive to run with our need to feed. But it’s probably not the whole story. Like many other neurobiological events, the exact recipe for runner’s high is complex and hazy. It takes a whole suite of chemicals to help us get started and to make sure we want to go the distance. Those who get runner’s high know it when they feel it. But a clinical definition is a little more slippery. “I remember someone saying the runner’s high was the moment when the body was disconnected from the brain,” says Francis Chaouloff, who studies running and motivation in mice at the French Institute of Health and Medical Research in Bordeaux. This sense of extreme euphoria, he says, is generally limited to people running or exercising for long periods of time, over many miles or hours. © Society for Science & the Public 2000 - 2015.
Jon Hamilton A mind-altering drug called ketamine is changing the way some doctors treat depression. Encouraged by research showing that ketamine can relieve even the worst depression in a matter of hours, these doctors are giving the drug to some of their toughest patients. And they're doing this even though ketamine lacks approval from the Food and Drug Administration for treating depression. "It became clear to me that the future of psychiatry was going to include ketamine or derivatives of ketamine," says David Feifel, a professor of psychiatry at the University of California, San Diego, who began administering the drug to patients in 2010. Ketamine was developed as an anesthetic and received FDA approval for this use in 1970. Decades later, it became popular as a psychedelic club drug. And in 2006, a team from the National Institute of Mental Health published a landmark study showing that a single intravenous dose of ketamine produced "robust and rapid antidepressant effects" within a couple of hours. Since then, thousands of depressed patients have received "off-label" treatment with ketamine. One of those patients is Paul, 36, who lives in San Diego and is a patient of Dr. Feifel. We're not using his last name to protect his medical privacy. © 2015 NPR
By Karen Weintraub Depression makes people more vulnerable to alcoholism and vice versa, said Dr. Shelly Greenfield, a professor of psychiatry at Harvard Medical School and director of McLean Hospital’s Alcohol and Drug Abuse Clinical and Health Services Research Program. About a third of depressed people also have a problem with alcohol, she said, adding that the depression usually comes first. Genetics makes some people more vulnerable to each — and perhaps the combination, Dr. Greenfield said, “but it’s not the whole story.” Social environment, particularly in childhood, also plays a key role. People who are the victims of physical or sexual abuse, for example, are at higher risk for both alcoholism and depression later in life, she said. Depressed people who drink will most likely see their depression worsen, because alcohol is a depressant, tamping down the nervous system, said Dr. Kathleen Brady, a distinguished university professor at the Medical University of South Carolina. Abstinence will be harder for alcoholics who are depressed, because of the hopelessness that comes with depression. Getting help promptly may make recovery from alcoholism easier, Dr. Greenfield said. Needing help to quit drinking or to resolve depression is not a sign of weakness or personal failure, she noted. In families with a history of either depression or alcoholism, it is important to be vigilant about drinking, particularly in adolescence. © 2015 The New York Times Company
Nathan Seppa For a historically mistrusted drink, coffee is proving to be a healthy addiction. Scientific findings in support of coffee’s nutritional attributes have been arriving at a steady drip since the 1980s, when Norwegian researchers reported that coffee seemed to fend off liver disease. Since then, the dark brown beverage has shown value against liver cancer, too, as well as type 2 diabetes, heart disease and stroke. Coffee even appears to protect against depression, Parkinson’s and Alzheimer’s diseases. Taken as a whole, these results might explain the most astonishing finding of all. People who drink two or more cups of coffee a day live longer than those who don’t, after accounting for behavioral differences, U.S. researchers reported in 2012. Studies in Japan, Scotland and Finland agree. Talk about a twofer. Coffee not only picks you up, it might put off the day they lower you down. Yet coffee has had trouble shaking its bad-for-you reputation. It may be one of the most widely consumed drinks in the world, but people have long assumed that, at least in its energizing caffeinated version, coffee comes with a catch. “People notice the caffeine,” says cardiologist Arthur Klatsky, who has researched coffee for decades at the Kaiser Permanente Northern California Division of Research in Oakland. “And there is this general feeling that anything that has some effect on the nervous system has to have something bad about it.” It doesn’t help that caffeine is mildly addictive.
A particular region of the brain may drive smoking addiction, say scientists who found stroke survivors with damage to their insular cortex more easily kicked the habit. They studied 156 stroke patients with different patterns of brain injury. More of those with insular cortex damage successfully gave up smoking and reported fewer withdrawal symptoms than the other stroke patients. Experts say targeting this brain area may help other smokers quit. Most stop smoking medicines currently on the market work by blocking the brain's reward pathways in response to nicotine. And patches and gums aim to lessen cravings by supplying a controlled dose of nicotine as the person weans themselves off tobacco. But post-graduate researcher Amir Abdolahi and colleagues believe the insular cortex could be a valuable new target for quit smoking aids. Therapies that could hone in on this area of the brain and disrupt its role in addiction, potentially with new drugs or other techniques such as deep brain stimulation or transcranial magnetic stimulation, should be explored, they say. "Much more research is needed in order for us to more fully understand the underlying mechanism and specific role of the insular cortex, but it is clear that something is going on in this part of the brain that is influencing addiction," Mr Abdolahi said. The research findings are published in two medical journals - Addiction and Addictive Behaviors. The patients in the study were smokers who had been admitted to hospital because of a stroke. Medical scans revealed that 38 of them had suffered damage to the insular cortex, while the remaining 118 had damage to other parts of the brain. All of the patients were encouraged by their doctor to quit smoking. © 2015 BBC.
Keyword: Drug Abuse
Link ID: 21385 - Posted: 09.08.2015
By Roni Caryn Rabin Q: Is it harmful to go on and off antidepressants a few times a year? I seem to respond quickly and quite well to S.S.R.I.'s. I don't desire to be on them long-term, but would like to use them occasionally, to get through a rough patch like a stressful quarter at work. Is it harmful to go on and off of S.S.R.I.'s a few times a year? Yes, it may be harmful. You should always start and stop medication “under a physician’s supervision. Don’t do it on your own,” said Dr. Renee Binder, president of the American Psychiatric Association. It usually takes at least four weeks for an antidepressant to take effect, and patients should give themselves several weeks to taper off a drug when ending treatment. Starting and quitting abruptly expose you to the risks of initiation and withdrawal. Also, you may not get sustained relief from your depression. Antidepressants “don’t work right away,” Dr. Binder said. “It’s the kind of medication that you have to take every single day, and it takes awhile to build up in your body before it starts working.” When starting antidepressants, patients may experience anxiety and agitation and develop other transient side effects like headaches and nausea. Teenagers need close monitoring because they may be at a higher risk of suicide when starting treatment, some studies suggest. It also may take time for your doctor to find the antidepressant and dose that’s right for you. Withdrawal can trigger troubling symptoms like nausea, dizziness and “brain zaps,” a sensation that feels like electric shocks to the head. It can also trigger psychological problems like anxiety, irritability, moodiness and changes in appetite and sleep that mimic depression or may signal a recurrence. Some patients may become paranoid or suicidal. © 2015 The New York Times Company
Link ID: 21363 - Posted: 08.31.2015
Raiding the fridge or downing glasses of water after a night of heavy drinking won't improve your sore head the next day, Dutch research suggests. Instead, a study concluded, the only way to prevent a hangover is to drink less alcohol. More than 800 students were asked how they tried to relieve hangover symptoms, but neither food nor water was found to have any positive effect. The findings are being presented at a conference in Amsterdam. A team of international researchers from the Netherlands and Canada surveyed students' drinking habits to find out whether hangovers could be eased or if some people were immune to them. Among 826 Dutch students, 54% ate food after drinking alcohol, including fatty food and heavy breakfasts, in the hope of staving off a hangover. With the same aim, more than two-thirds drank water while drinking alcohol and more than half drank water before going to bed. Although these groups showed a slight improvement in how they felt compared with those who hadn't drunk water, there was no real difference in the severity of their hangovers. Previous research suggests that about 25% of drinkers claim never to get hangovers. So the researchers questioned 789 Canadian students about their drinking in the previous month and the hangovers they experienced, finding that those who didn't get a hangover simply consumed "too little alcohol to develop a hangover in the first place". Of those students who drank heavily, with an estimated blood alcohol concentration of more than 0.2%, almost no-one was immune to hangovers. © 2015 BBC.
Keyword: Drug Abuse
Link ID: 21356 - Posted: 08.29.2015
by Bethany Brookshire You’ve already had a muffin. And a half. You know you’re full. But there they are, fluffy and delicious, waiting for the passersby in the office. Just thinking about them makes your mouth water. Maybe if you just slice one into quarters. I mean, that barely counts… And then we give in, our brains overriding our body’s better judgment. When I catch myself once again polishing off a whole plate of baked goods, I wish that there was something I could do, some little pill I could take that would make that last delicious bite look — and taste — a little less appealing. But the more scientists learn about the human body, the more they come to understand that there is no one set of hormones for hungry, with a separate set that kicks off your ice cream binge. Instead, our guts and their hormones are firmly entwined with our feelings of reward and motivation. That close relationship shows just how important it is to our bodies to keep us fed, and how hard it is to stop us from overeating. Researchers have long divided our feeding behavior into two distinct categories. One, the homeostatic portion, is primarily concerned with making sure we’ve got enough energy to keep going and is localized to the lateral hypothalamus in the brain. The reward-related, or “hedonic,” component is centralized in the mesolimbic dopamine system, areas of the brain usually referenced when we talk about the effects of sex, drugs and rock ’n’ roll. © Society for Science & the Public 2000 - 2015
Daniel Cressey In 2013, Beau Kilmer took on a pretty audacious head count. Citizens in the state of Washington had just voted to legalize marijuana for recreational use, and the state's liquor control board, which would regulate the nascent industry, was anxious to understand how many people were using the drug — and importantly, how much they were consuming. The task was never going to be straightforward. Users of an illicit substance, particularly heavy users, often under-report the amounts they take. So Kilmer, co-director of the RAND Drug Policy Research Center in Santa Monica, California, led a team to develop a web-based survey that would ask people how often they had used cannabis in the past month and year. To help them gauge the amounts, the surveys included scaled pictures showing different quantities of weed. The survey, along with other data the team had collected, revealed a rift between perception and reality. Based on prior data, state officials had estimated use at about 85 tonnes per year; Kilmer's research suggested that it was actually double that, about 175 tonnes1. The take-home message, says Kilmer, was “we're going to have to start collecting more data”. Scientists around the world would echo that statement. Laws designed to legalize cannabis or lessen the penalties associated with it are taking effect around the world. They are sweeping the sale of the drug out of stairwells and shady alleys and into modern shopfronts under full view of the authorities. In 2013, Uruguay became the first nation to legalize marijuana trade. And several countries in Europe — Spain and Italy among them — have moved away from tough penalties for use and possession. Thirty-nine US states plus Washington DC have at least some provisions for medicinal use of the drug. Washington, Colorado, Alaska and Oregon have gone further, legalizing the drug for recreational consumption. A handful of other states including California and Massachusetts are expected to vote on similar recreational-use measures by the end of 2016. © 2015 Nature Publishing Group
Keyword: Drug Abuse
Link ID: 21315 - Posted: 08.19.2015
By Lisa Rapaport (Reuters Health) - U.S. teens who try electronic cigarettes may be more than twice as likely to move on to smoking conventional cigarettes as those who have never tried the devices, report researchers from the University of Southern California. The findings, published August 18 in JAMA, offer some of the best evidence yet at establishing a link between e-cigarettes and smoking, said Dr. Nancy Rigotti, an expert in tobacco research at Massachusetts General Hospital and author of an editorial accompanying the study. "Adolescent brains appear to be especially susceptible to becoming addicted to nicotine when exposed," Rigotti told Reuters Health in an email. About 2 million middle- and high-school students tried e-cigarettes in 2014, triple the number of teen users in 2013, the Centers for Disease Control and Prevention reported in April. The data sparked alarm among tobacco control advocates who fear e-cigarettes will create a new generation of nicotine addicts who may eventually switch to conventional cigarettes. Big tobacco companies, including Altria Group Inc, Lorillard Tobacco Co and Reynolds American Inc, are all developing e-cigarettes. The battery-powered devices feature a glowing tip and a heating element that turns liquid nicotine and other flavorings into a cloud of vapor that users inhale. An international review of published research by the Cochrane Review in December concluded that the devices could help smokers quit but said much of the existing evidence on e-cigarettes was thin. © 2015 Scientific American
Keyword: Drug Abuse
Link ID: 21314 - Posted: 08.19.2015
By Robert F. Service Move over, poppies. In one of the most elaborate feats of synthetic biology to date, a research team has engineered yeast with a medley of plant, bacterial, and rodent genes to turn sugar into thebaine, the key opiate precursor to morphine and other powerful painkilling drugs that have been harvested for thousands of years from poppy plants. The team also showed that with further tweaks, the yeast could make hydrocodone, a widely used painkiller that is now made chemically from thebaine. “This is a major milestone,” says Jens Nielsen, a synthetic biologist at Chalmers University of Technology in Göteborg, Sweden. The work, he adds, demonstrates synthetic biology’s increasing sophistication at transferring complex metabolic pathways into microbes. By tweaking the yeast pathways, medicinal chemists may be able to produce more effective, less addictive versions of opiate painkillers. But some biopolicy experts worry that morphinemaking yeast strains could also allow illicit drugmakers to brew heroin as easily as beer enthusiasts home brew today—the drug is a simple chemical conversion from morphine. That concern is one reason the research team, led by Christina Smolke, a synthetic biologist at Stanford University in Palo Alto, California, stopped short of making a yeast strain with the complete morphine pathway; medicinal drug makers also primarily use thebaine to make new compounds. Synthetic biologists had previously engineered yeast to produce artemisinin, an antimalarial compound, but that required inserting just a handful of plant genes. To get yeast to make thebaine, © 2015 American Association for the Advancement of Science.
By Janet Davison, CBC News Maddy Huggins would binge drink as a teenager and black out, just like other kids at her high school in Kelowna, B.C. When she went backpacking during her gap year, there were more alcoholic overloads and "really risky" moments when something bad could have transpired. "Nothing too terrible happened, but there was the potential for that," says Huggins, 22, who's just about to start fourth year at the University of Saskatchewan. As she settled into university, however, Huggins did some serious thinking about alcohol in her life. "It was just a gradual progression where I was like, 'OK, enough of this.'" These days, Huggins knows her low-risk alcoholic limits and won't hesitate to order water even if her friends are going for something stronger. But other young Canadian women haven't stepped back like that. Reports suggest the percentage of young women binge drinking — defined now as having at least four drinks per occasion at least once a month — is on the rise and encompasses nearly one in four Canadian women between 20 and 34. Indeed, the trend has become so pronounced that the Paris-based Organization of Economic Co-operation and Development warned in May that binge drinking by young people, including in Canada, has become a "major public health and social concern." Looming problems It's a concern that goes beyond the headline issues like date rape and campus horrors to where health scientists are warning that because of physiology — women generally weigh less than men, have a higher percentage of body fat and smaller livers — excessive drinking by young women is setting them up for a series of health problems down the road. ©2015 CBC/Radio-Canada
RACHEL MARTIN, HOST: Every day, according to the Centers for Disease Control, 44 Americans die because they have overdosed on prescription painkillers. The CDC calls it an epidemic, and drug companies are responding by trying to develop versions of the most addictive painkillers, opioids, that will diminish a user's physical craving for the medicine. Now, to do this, to create these less addictive drugs, pharmaceutical companies are recruiting thousands of self-identified drug users to test their products. David Crow is a reporter for the Financial Times. He's just published a big report on this, and he joins me now to talk more about it. Thanks so much for being with us. Opioids, as we mentioned, are the worst in terms of their addictive quality. These companies are trying to come up with drugs that will achieve the same painkilling effect without the addictiveness. So this is actually possible? CROW: What they're trying to do is develop a new generation of opioid painkillers that have features that make them harder to abuse. Some of the strategies that have been pursued include hard shells that make it harder to crush up the pill so that you can snort it or gumming agents that make it harder to put into a syringe so that you can inject it. And some companies are experimenting with putting different chemicals in the center of the pill that will remain dormant. But if it's tampered with, that chemical would be released, and it would counteract the effect of the opioid. They're testing these drugs on recreational drug users. And the participants go through a screening process where they have to wash out, where they don't have any opioid in their system, and also where they're given a drug called naloxone, which cuts off the effects of opioids. And at that point, if you were addicted or physically dependent, your body would show signs of withdrawal. And that is the screening process. © 2015 NPR
Kill, Fido! Docile ants become aggressive guard dogs after a secret signal from their caterpillar overlord. The idea turns on its head the assumption that the two species exchange favours in an even-handed relationship. The caterpillars of the Japanese oakblue butterfly (Narathura japonica) grow up wrapped inside leaves on oak trees. To protect themselves against predators like spiders and wasps, they attract ant bodyguards, Pristomyrmex punctatus, with an offering of sugar droplets. The relationships was thought to be a fair exchange of services in which both parties benefit. But Masaru Hojo from Kobe University in Japan noticed something peculiar: the caterpillars were always attended by the same ant individuals. “It also seemed that the ants never moved away or returned to their nests,” he says. They seemed to abandon searching for food, and were just standing around guarding the caterpillar. Intrigued, Hojo and his colleagues conducted lab experiments in which they allowed some ants to interact with the caterpillars and feed on the secretions, and kept others separate. Ants that ate the caterpillar’s secretions remained close to the caterpillar. They didn’t return to their nest. And whenever the caterpillar everted its tentacles – flipped them so they turned inside out – the ants moved around rapidly, acting aggressively. © Copyright Reed Business Information Ltd.
By Christie Wilcox Venomous cone snails have been a gift to biomedical researchers. Over the past 50 years, scientists have isolated compounds from these predatory marine animals that do everything from stop pain to protect cells during a heart attack. Now, researchers have isolated a cone snail compound that does something unexpected: It puts mice to sleep. All of these compounds belong to a group of ion channels modifiers known as conotoxins. In the wild, the snails use these toxins for capturing prey, and typically when researchers inject them into mice, the rodents either have no response or become paralyzed. In the new study, published this month in Toxicon, researchers isolated and sequenced 14 novel peptide toxins from the venom of the cobweb cone, Conus araneosus (pictured above with its dissected venom gland). When they injected five of them into mice, one put the rodents to sleep for several hours, whereas the others had no effect. The team says the discovery expands the range of therapeutic uses for conotoxins, and could lead to drugs to treat sleep disorders. © 2015 American Association for the Advancement of Science
By BENEDICT CAREY Bill Cosby stands accused of committing date rape long before drugs like GHB or Rohypnol were widely used for that purpose. Many of Mr. Cosby’s accusers believed they had been drugged — but with what? And how? In a recently obtained legal deposition, Mr. Cosby acknowledged giving quaaludes to some women with whom he had sex, but said consumption of the drug was consensual, “the same as a person would say, ‘Have a drink.’ ” In a transcript of the deposition, reported on Sunday in The New York Times, the comedian told lawyers had had obtained seven prescriptions for quaaludes. Originally approved and marketed as a “safer” sleeping pill, less addictive than barbiturates, the drug (known generically as methaqualone) was both sedating and hypnotic. Recreational use was common, but the federal government withdrew them from the market in 1982. “It was inevitable that it would be tried by people looking for a ‘better high,’ ” Dr. David Smith, medical director of the Haight-Ashbury Free Clinic, and Dr. Donald Wesson noted in The Journal of Psychedelic Drugs. Intoxication with quaaludes “soon developed a reputation for being especially pleasant.” Young people in the 1970s used quaaludes as they would a strong drink: to loosen up, to relax, to socialize. The pills also won a reputation for inducing periods of euphoria, as well as sexual arousal — “heroin for lovers,” some called it. By the middle of the decade, quaaludes were a staple of the club scene, often taken with alcohol. So embedded were quaaludes in the cultural scene that even years later the Dead Kennedys and Billy Idol were singing about the drug’s captivating effects. But reckless users risked overdose, especially when combining the pills with alcohol, which could lead to coma, convulsions and sometimes death. In a 1973 review of 252 hospital admissions for drug overdose, doctors in Edinburgh found that the third most common cause of “self-poisoning,” after barbiturates and LSD, was Mandrax — the British version of quaaludes, widely abused in South Africa as well. © 2015 The New York Times Company
Keyword: Drug Abuse
Link ID: 21198 - Posted: 07.22.2015
Don’t do drugs, kids. Especially if you’re female. Women dependent on stimulants like cocaine and methamphetamine appear to have less grey matter, even after they stop using them. Weirdly, men’s brains don’t show this difference. The brain regions most affected are those involved in reward, emotion and learning – although it isn’t clear yet whether the smaller than average size of these brain areas could be a cause or effect of addiction. Jody Tanabe, at the University of Colorado Hospital in Aurora, hopes these results will help lead to a better understanding of sex differences in substance abuse, and better, more distinct treatments for women. Tanabe’s team used MRI scans to measure the brain volumes of 59 people previously dependent on stimulants and compared them with people who have never been dependent on these kinds of drugs. On average, the 28 women who had formerly been dependent on a stimulant drug had a smaller volume of grey matter in their prefrontal cortices, temporal lobes, insulae and other regions. This effect was not seen in men. Shrinking brains The women who had been addicted also differed in their personalities – on average, they were more impulsive and more reward-driven. We already know that women respond differently to stimulants: they start taking the drugs earlier, use larger quantities and may have more difficulty quitting. It’s possible that this pattern of female addiction could be linked to the brain size difference. However, it’s unclear whether less grey matter causes female addictive behaviours, or if addiction might shrink these brain regions. “The question of causality is complex. There is evidence for both pre-existing and post-drug changes in brain structure and function,” says Tanabe.
OLIVER SACHGAU Marc Lewis spends a lot of his time thinking about addiction. He has good reason to: In his 20s he struggled with his own addiction to opiates. He was eventually able to quit, and began researching addiction and neuroscience. Mr. Lewis became a professor of developmental psychology at the University of Toronto in 1989, and moved to Radboud University in the Netherlands in 2010. His new book, The Biology of Desire: Why Addiction is Not a Disease, looks at the neuroscience of addiction, mixing personal narratives with scientific data. The book will be released in Canada on Aug. 4. You argue addiction is not a disease, but an example of very normal brain activity. What do you mean? [It’s] an exaggerated form of learning. Let’s put it that way. People in neuroscience agree that addiction corresponds with brain changes, and that’s the basis of the disease argument: That addiction changes the brain, or hijacks the brain, as they say. As though it were a pathology or disease process. Whereas I argue that all learning changes – the brain is designed to change – but when you have highly motivated learning, especially something that gets repeated over and over, then the learning curve rises extremely rapidly, and you have a kind of exaggerated learning phenomenon, where the learning is deep and specialized, and blots out other available habits or other available perceptions. You chose to mix hard scientific data with these anecdotal stories. How come? I love that way of writing. It seems to me so amazing that brain changes are going on at the same time as lived experiences: The moment-to-moment changes of thoughts and feelings are completely yoked to changes and activity in your brain, but it’s almost impossible to tell both stories at the same time, because one is under the skin, in terms of cell firings and electrochemical impulses and stuff, and the other one is in terms of behavior and human values and norms and so forth. © Copyright 2015 The Globe and Mail Inc