Chapter 4. The Chemistry of Behavior: Neurotransmitters and Neuropharmacology
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By ANDREW POLLACK An experimental drug derived from marijuana has succeeded in reducing epileptic seizures in its first major clinical trial, the product’s developer announced on Monday, a finding that could lend credence to the medical marijuana movement. The developer, GW Pharmaceuticals, said the drug, Epidiolex, achieved the main goal of the trial, reducing convulsive seizures when compared with a placebo in patients with Dravet syndrome, a rare form of epilepsy. GW shares more than doubled on Monday. If Epidiolex wins regulatory approval, it would be the first prescription drug in the United States that is extracted from marijuana. The drug is a liquid containing cannabidiol, a component of marijuana that does not make people high. As many as 30 percent of the nearly 500,000 American children with epilepsy are not sufficiently helped by existing drugs, according to GW. Parents of some of these children have been flocking to try marijuana extracts, prepared by medical marijuana dispensaries. A number of states, in response to pressure from these parents, have passed or considered legislation to make it easier to obtain marijuana-based products. And some families have become “marijuana refugees,” moving to Colorado where it has been easier to obtain a particular extract, known as Charlotte’s Web, after the girl who first used it to control seizures. Hundreds of other children and young adults have been using Epidiolex outside of clinical trials, under programs that allow desperate patients to use experimental drugs. While many parents have reported significant reductions in seizures, experts have been cautious about anecdotal reports, saying that such treatments needed to be compared with a placebo to make sure they work. As such, the results from the GW trial have been closely watched. © 2016 The New York Times Company
By KATHARINE Q. SEELYE CAMBRIDGE, Mass. — In Philadelphia last spring, a man riding a city bus at rush hour injected heroin into his hand, in full view of other passengers, including one who captured the scene on video. In Cincinnati, a woman died in January after she and her husband overdosed in their baby’s room at Cincinnati Children’s Hospital Medical Center. The husband was found unconscious with a gun in his pocket, a syringe in his arm and needles strewn around the sink. Here in Cambridge a few years ago, after several people overdosed in the bathrooms of a historic church, church officials reluctantly closed the bathrooms to the public. “We weren’t medically equipped or educated to handle overdoses, and we were desperately afraid we were going to have something happen that was way out of our reach,” said the Rev. Joseph O. Robinson, rector of the church, Christ Church Cambridge. With heroin cheap and widely available on city streets throughout the country, users are making their buys and shooting up as soon as they can, often in public places. Police officers are routinely finding drug users — unconscious or dead — in cars, in the bathrooms of fast-food restaurants, on mass transit and in parks, hospitals and libraries. The visibility of drug users may be partly attributed to the nature of the epidemic, which has grown largely out of dependence on legal opioid painkillers and has spread to white, urban, suburban and rural areas. © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 21961 - Posted: 03.07.2016
By ANNA FELS THERE was something odd about my new patient. She was elegantly dressed and self-possessed, and yet she was slowly, rhythmically chewing gum, something I rarely see in my psychiatry sessions. Was she trying to cover up anxiety about this first encounter, I wondered, or was she perhaps hoping to project a kind of cool, laid-back style? We talked for a long time about why she had come to see me. Then, as is my practice with a new patient, I asked what, if any, psychiatric medications and nonprescription, psychoactive substances — legal or illegal — she had used. Her answer was a new one for me. She stated that she chewed approximately 40 pieces of nicotine gum per day and had done so for well over a decade. Responses to this question are often illuminating and can be rather humbling. Although doctors are trained to focus on prescription medications, there are and have always been nonprescription “remedies” for psychiatric conditions. And people’s preferences for one type of substance over another can give a glimpse into their symptoms and even their brain chemistry. If a patient tells me he falls asleep on cocaine, I wonder if he might have attention deficit disorder. A patient who smokes marijuana to calm down before important business meetings leads me in the direction of social phobia or other anxiety disorders. I often wonder if people who take ketamine recreationally might be depressed, since this anesthetic has been shown to have antidepressant effects and is, in fact, being investigated for potential therapeutic use. Sorting through patients’ uses of psychoactive substances, from cocaine to alcohol to coffee, leaves me with an appreciation of the wildly different neurochemistry of people’s brains. One person will drink alcohol and feel euphoric, witty and extroverted, and the next will be logy and nauseated. © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 21960 - Posted: 03.07.2016
Angus Chen We know we should put the cigarettes away or make use of that gym membership, but in the moment, we just don't do it. There is a cluster of neurons in our brain critical for motivation, though. What if you could hack them to motivate yourself? These neurons are located in the middle of the brain, in a region called the ventral tegmental area. A paper published Thursday in the journal Neuron suggests that we can activate the region with a little bit of training. The researchers stuck 73 people into an fMRI, a scanner that can detect what part of the brain is most active, and focused on that area associated with motivation. When the researchers said "motivate yourself and make this part of your brain light up," people couldn't really do it. "They weren't that reliable when we said, 'Go! Get psyched. Turn on your VTA,' " says Dr. Alison Adcock, a psychiatrist at Duke and senior author on the paper. That changed when the participants were allowed to watch a neurofeedback meter that displayed activity in their ventral tegmental area. When activity ramps up, the participants see the meter heat up while they're in the fMRI tube. "Your whole mind is allowed to speak to a specific part of your brain in a way you never imagined before. Then you get feedback that helps you discover how to turn that part of the brain up or down," says John Gabrieli, a neuroscientist at the Massachusetts Institute of Technology who was not involved with the work. © 2016 npr
Link ID: 21954 - Posted: 03.05.2016
Ewan Birney The Daily Mail recently ran an article about how alcohol abuse could harm future generations, via the (exciting-sounding) mechanism of trans-generational epigenetics. This is an emotive topic, combining a commonplace habit (drinking beer and wine) with a scary outcome (harming your children, grandchildren and future generations) and adding a twist of science for gravitas. It’s not surprising that this research has been handed a megaphone by the mainstream press – but does the science stack up? To start with, the research was carried out in rats, as multi-generational experiments on humans are both grossly unethical and logistically extremely hard. This crucial bit of information is missing from both the Daily Mail headline and the paper’s title. Secondly, the big effects of alcohol consumption were mainly seen on the rats’ children and grandchildren – the effects on their great grandchildren were smaller. That is really important, because if there’s no effect on great grandchildren, it’s probably not due to epigenetics. Drinking large amounts of alcohol (for a rat) whilst pregnant would be expected to have an effect on the children and even the grandchildren. This is because the eggs of female mammals are made early on in foetal development, whilst a daughter is developing in the womb. So if that cell (the egg) also gives rise to a daughter, she will have directly experienced exposures that occurred during her maternal grandmother’s pregnancy. © 2016 Guardian News and Media Limited or its affiliated companies.
With the opioid epidemic reaching into every corner of the U.S., more people are talking about addiction as a chronic disease rather than a moral failing. For researcher A. Thomas McLellan, who has spent his entire career studying substance abuse, the shift is a welcome one, though it has come frustratingly late. McLellan is co-founder of the Treatment Research Institute in Philadelphia and former deputy director of the White House Office of National Drug Control Policy. His work has focused on understanding addiction as a disease and improving the ways it is treated, a mission that took a personal turn midway through his career when he lost a son to overdose. NPR's Audie Cornish spoke with McLellan about how addiction is viewed and how that view has shaped the treatment system we have today. He also has suggestions on how to make it better. On why addiction has traditionally been seen as a criminal justice issue, not a health issue Think about it. If you didn't have brain science, which has just really emerged in the last two or three decades, all you had to look at was the behavior of addicted people. They are not pleasant people when they are in full addiction. They steal, they lie, they swear they're going to do something and they don't. It's quite easy to think of this as it has been thought of for literally hundreds of years: as a character disorder, as poor upbringing as a problem of parenting. And that's how we approached it. It's not coincidence that the Justice Department has played such a pivotal role. The emerging science shows this is a brain disease. It's got the same genetic transmutability as a lot of chronic illnesses. And the organ that it affects is the brain, and within the brain it is motivation, inhibition, cognition, all those things that produce the aberrant, unpleasant behaviors that are associated with addiction. © 2016 npr
Keyword: Drug Abuse
Link ID: 21935 - Posted: 02.27.2016
By Roni Caryn Rabin Fatal prescription-drug overdoses in the United States have increased sharply in recent years. But while most of the deaths have involved opioid painkillers like oxycodone, a new study suggests that anti-anxiety medications now are playing an outsize role in overdose deaths. The number of Americans filling prescriptions for anti-anxiety drugs — benzodiazepines like Valium and Xanax that are used to treat anxiety, panic disorders and insomnia — increased 67 percent between 1996 and 2013, the study found. But the rate of overdose deaths involving these drugs increased more than fourfold. The analysis, published online last week in The American Journal of Public Health, found that 5.6 percent of American adults filled a benzodiazepine prescription in 2013, up from 4.1 percent in 1996. (The actual number of Americans filling a benzodiazepine prescription rose to 13.5 million in 2013, up from 8.1 million in 1996.) Meanwhile, the rate of overdose deaths involving anti-anxiety drugs reached 3.07 per 100,000 adults in 2013, up from 0.58 per 100,000 adults in 1996. With public attention focused primarily on opioid painkillers, the role of anti-anxiety drugs “fell under the radar,” said Dr. Marcus Bachhuber, the study’s author and an assistant professor of medicine at Montefiore Medical Center/Albert Einstein College of Medicine in the Bronx. Yet when benzodiazepines are abused or combined with other drugs or alcohol, they contribute to depressing the respiratory system, which can be deadly, he said. “If we’re going to address the prescription drug crisis, we can’t just focus on opioids,” he said. “We need to think more broadly about other drugs, like benzodiazepines.” © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 21934 - Posted: 02.27.2016
By GABRIELLE GLASER On the rainy fall morning of their first appointment, Dr. Mark Willenbring, a psychiatrist, welcomed a young web designer into his spacious office with a firm handshake and motioned for him to sit. The slender 29-year-old patient, dressed in a plaid shirt, jeans and a baseball cap, slouched into his chair and began pouring out a story of woe stretching back a dozen years. Addicted to heroin, he had tried more than 20 traditional faith- and abstinence-based rehabilitation programs. In 2009, a brother died of an OxyContin overdose. Last summer, he attempted suicide by swallowing a fistful of Xanax. When he woke up to find he was still alive, he overdosed on heroin. At a boot camp for troubled teenagers, he said, staffers beat him and withheld food. After he refused to climb a mountain in a team-building exercise, they strapped him to a gurney and dragged him up themselves. The young man in the psychiatrist’s office paused, tears sliding down his cheeks. “Sounds like a prison camp,” Dr. Willenbring said softly, leaning forward in his chair to pass a box of tissues. He began explaining the neuroscience of alcohol and drug dependence, 60 percent of which, he said, is attributable to a person’s genetic makeup. Listening intently, the young patient seemed relieved at the idea that his previous failures in rehab might reflect more than a lack of will. Dr. Willenbring, 66, has repeated this talk hundreds of times. But while scientifically unassailable, it is not what patients usually hear at addiction treatment centers. © 2016 The New York Times Company
Keyword: Drug Abuse
Link ID: 21925 - Posted: 02.23.2016
Allison Aubrey It's no secret that stimulant medications such as Adderall that are prescribed to treat symptoms of ADHD are sometimes used as "study drugs" aimed at boosting cognitive performance. And emergency room visits linked to misuse of the drug are on the rise, according to a study published Tuesday in the Journal of Clinical Psychiatry. "Young adults in the 18- to 25-year age range are most likely to misuse these drugs," says Dr. Ramin Mojtabai, a professor at the Johns Hopkins Bloomberg School of Public Health and senior author of the study. A common scenario is this: A person who has been prescribed ADHD drugs gives or diverts pills to a friend or family member who may be looking for a mental boost, perhaps to cram for a final or prepare a report. And guess what? This is illegal. Overall, the study found that nonmedical use of Adderall and generic versions of the drug increased by 67 percent among adults between 2006 and 2011. The findings are based on data from the National Survey on Drug Use and Health. The number of emergency room visits involving Adderall misuse increased from 862 visits in 2006 to 1,489 in 2011 according to data from the Drug Abuse Warning Network . © 2016 npr
By SINDYA N. BHANOO The human brain is attracted to things that were once pleasing even if they no longer are, researchers report. Study participants were asked to find red and green objects on a computer screen filled with different colored objects. They received small rewards for finding the objects: $1.50 for the red ones and 25 cents for the green ones. The next day, while brain scans were conducted, participants were asked to find certain shapes on the screen. There was no reward, and color was irrelevant. Still, when a red object appeared, participants focused on it, and scans showed dopamine was released in their brains. “They are not getting a reward for that, yet part of the brain is saying, ‘Oh, there’s a reward — pay attention to it,’” said Susan M. Courtney, a cognitive neuroscientist at Johns Hopkins University and a co-author of the study in Current Biology. The findings may help researchers develop pharmaceutical treatments for problems like food or drug addiction. © 2016 The New York Times Company
Janet Raloff WASHINGTON ― Many people have turned to electronic cigarettes in hopes of avoiding the heart and cancer risks associated with smoking conventional tobacco products. But vaping appears far from benign, a trio of toxicologists reported February 11 and 12 at the American Association for the Advancement of Science annual meeting. If used as a means to totally wean people off of tobacco products, then e-cigarettes might have value, concedes Ilona Jaspers of the University of North Carolina at Chapel Hill. But she’s not sure. Unpublished data that she and the others presented at the meeting link e-cig products to a host of new risks. So vaping may not eliminate risks associated with conventional smoking, Jaspers maintains ― “and may actually be introducing new ones.” Her group examined scraped cells from the noses of otherwise healthy people who had a history of smoking, vaping or doing neither. The researchers then measured the activity levels in these cells of 594 genes associated with the body’s ability to fight infections. Among smokers, the activity of 53 genes was substantially diminished, compared with people who neither smoked nor vaped. Among vapers, those same 53 genes showed significantly diminished activity, Jaspers reported, as did 305 more. The normal role of these genes would suggest that the lung tissue as well as nasal tissue of smokers ― and especially vapers ―“may be more susceptible to any kind of infection.” © Society for Science & the Public 2000 - 2016.
Keyword: Drug Abuse
Link ID: 21889 - Posted: 02.13.2016
Could a painkiller turn people away from suicide? A preliminary trial of an opioid called buprenorphine shows that the drug can reduce suicidal thoughts after just one week. If validated in larger studies, it could become the first fast-acting anti-suicide drug. Such a drug is sorely needed. The US Centers for Disease Control and Prevention (CDC) estimates that more than 9 million adults in the country reported having suicidal thoughts in 2013. Over a million went on to attempt suicide. “Around 400,000 suicidal people are coming to emergency rooms every year,” says Elizabeth Ballard at the National Institute of Mental Health. “Pharmacologically, nothing has been approved for acute treatment of suicidal ideation so anything that can help them is greatly needed.” When people seek help, they may be offered behavioural therapy or drugs such as antidepressants. But neither of these is guaranteed to alleviate feelings, and both can take six weeks or more to kick in. Ketamine, a drug being considered as an immediate treatment, can cause hallucinations and its effects wear off quickly. “Having something you could use on your own outside of a hospital would be beneficial,” says Ballard. Jaak Panksepp at Washington State University and his colleagues decided to see whether an opioid can counter suicidal feelings. Opioids are one of the brain’s natural feel-good chemicals. They are released to relieve pain when we hurt ourselves, and are involved when we deal with mental pain, such as that caused by social rejection, a common trigger for suicidal thoughts. © Copyright Reed Business Information Ltd.
By Diana Kwon Antidepressants are some of the most commonly prescribed medications out there. More than one out of 10 Americans over age 12—roughly 11 percent—take these drugs, according to a 2011 report by the National Center for Health Statistics. And yet, recent reports have revealed that important data about the safety of these drugs—especially their risks for children and adolescents—has been withheld from the medical community and the public. In the latest and most comprehensive analysis, published last week in BMJ (the British Medical Journal),a group of researchers at the Nordic Cochrane Center in Copenhagen showed that pharmaceutical companies were not presenting the full extent of serious harm in clinical study reports, which are detailed documents sent to regulatory authorities such as the U.S. Food and Drug Administration and the European Medicines Agency (EMA) when applying for approval of a new drug. The researchers examined documents from 70 double-blind, placebo-controlled trials of two common types of antidepressants—selective serotonin reuptake inhibitors (SSRI) and serotonin and norepinephrine reuptake inhibitors (SNRI)—and found that the occurrence of suicidal thoughts and aggressive behavior doubled in children and adolescents who used these medications. This paper comes on the heels of disturbing charges about conflicts of interest in reports on antidepressant trials. Last September a study published in the Journal of Clinical Epidemiology revealed that a third of meta-analyses of antidepressant studies were written by pharma employees and that these were 22 times less likely than other meta-studies to include negative statements about the drug. © 2016 Scientific American
Link ID: 21860 - Posted: 02.04.2016
By Sara Solovitch It was November 2012 when Dennis Hartman, a Seattle business executive, managed to pull himself out of bed, force himself to shower for the first time in days and board a plane that would carry him across the country to a clinical trial at the National Institute of Mental Health (NIMH) in Bethesda. After a lifetime of profound depression, 25 years of therapy and cycling through 18 antidepressants and mood stabilizers, Hartman, then 46, had settled on a date and a plan to end it all. This clinical trial would be his last stab at salvation. For 40 minutes, he sat in a hospital room as an IV drip delivered ketamine through his system. Several more hours passed before it occurred to him that all his thoughts of suicide had evaporated. “My life will always be divided into the time before that first infusion and the time after,” Hartman says today. “That sense of suffering and pain draining away. I was bewildered by the absence of pain.” Ketamine, popularly known as the psychedelic club drug Special K, has been around since the early 1960s. It is a staple anesthetic in emergency rooms, regularly used for children when they come in with broken bones and dislocated shoulders. It’s an important tool in burn centers and veterinary medicine, as well as a notorious date-rape drug, known for its power to quickly numb and render someone immobile.
By Dwayne Godwin, Jorge Cham Drugs and other stimuli hijack dopamine signaling in the brain, causing changes that can lead to addiction © 2016 Scientific America
Keyword: Drug Abuse
Link ID: 21845 - Posted: 02.02.2016
Jim Pfaus Self-labeled sex addicts often speak about their identities very clinically, as if they’re paralyzed by a scientific condition that functions the same way as drug and alcohol addiction. But sex and porn “addiction” are NOT the same as alcoholism or a cocaine habit. In fact, hypersexuality and porn obsessions are not addictions at all. They’re not included in the Diagnostic and Statistical Manual of Mental Disorders (DSM), and by definition, they don’t constitute what most researchers understand to be addiction. Here’s why: addicts withdraw. When you lock a dope fiend in a room without any dope, the lack of drugs will cause an immediate physiological response — some of which is visible, some of which we can only track from within the body. During withdrawal, the brains of addicts create junctions between nerve cells containing the neurotransmitter GABA. This process more or less inhibits the brain systems usually excited by drug-related cues — something we never see in the brains of so-called sex and porn addicts. A sex addict without sex is much more like a teenager without their smartphone. Imagine a kid playing Angry Birds. He seems obsessed, but once the game is off and it’s time for dinner, he unplugs. He might wish he was still playing, but he doesn’t get the shakes at the dinner table. There’s nothing going on in his brain that creates an uncontrollable imbalance.
by Graham McDougall, Jr., behavioral scientist at U. of Alabama Chemo brain is a mental cloudiness reported by about 30 percent of cancer patients who receive chemotherapy. Symptoms typically include impairments in attention, concentration, executive function, memory and visuospatial skills. Since the 1990s researchers have tried to understand this phenomenon, particularly in breast cancer patients. But the exact cause of chemo brain remains unclear. Some studies indicate that chemotherapy may trigger a variety of related neurological symptoms. One study, which examined the effects of chemotherapy in 42 breast cancer patients who underwent a neuropsychological evaluation before and after treatment, found that almost three times more patients displayed signs of cognitive dysfunction after treatment as compared with before (21 versus 61 percent). A 2012 review of 17 studies considering 807 breast cancer patients found that cognitive changes after chemotherapy were pervasive. Other research indicates that the degree of mental fogginess that a patient experiences may be directly related to how much chemotherapy that person receives: higher doses lead to greater dysfunction. There are several possible mechanisms to explain the cognitive changes associated with chemotherapy treatments. The drugs may have direct neurotoxic effects on the brain or may indirectly trigger immunological responses that may cause an inflammatory reaction in the brain. Chemotherapy, however, is not the only possible culprit. Research also shows that cancer itself may cause changes to the brain. In addition, it is possible that the observed cognitive decline may simply be part of the natural aging process, especially considering that many cancer patients are older than 50 years. © 2016 Scientific American,
By Emily Underwood In 2008, in El Cajon, California, 30-year-old John Nicholas Gunther bludgeoned his mother to death with a metal pipe, and then stole $1378 in cash, her credit cards, a DVD/VCR player, and some prescription painkillers. At trial, Gunther admitted to the killing, but argued that his conviction should be reduced to second-degree murder because he had not acted with premeditation. A clinical psychologist and neuropsychologist testified that two previous head traumas—one the result of an assault, the other from a drug overdose—had damaged his brain’s frontal lobes, potentially reducing Gunther’s ability to plan the murder, and causing him to act impulsively. The jury didn’t buy Gunther’s defense, however; based on other evidence, such as the fact that Gunther had previously talked about killing his mother with friends, the court concluded that he was guilty of first-degree murder, and gave him a 25-years-to-life prison sentence. Gunther’s case represents a growing trend, a new analysis suggests. Between 2005 and 2012, more than 1585 U.S. published judicial opinions describe the use of neurobiological evidence by criminal defendants to shore up their defense, according to a study published last week in the Journal of Law and the Biosciences by legal scholar Nita Farahany of Duke University in Durham, North Carolina, and colleagues. In 2012 alone, for example, more than 250 opinions cited defendants’ arguments that their “brains made them do it”—more than double the number of similar claims made in 2007. © 2016 American Association for the Advancement of Science
Keyword: Drug Abuse
Link ID: 21816 - Posted: 01.23.2016
By Diana Kwon Stories of cannabis’s abilities to alleviate seizures have been around for about 150 years but interest in medical marijuana has increased sharply in the last decade with the help of legalization campaigns. Credit: ©iStock Charlotte Figi, an eight-year-old girl from Colorado with Dravet syndrome, a rare and debilitating form of epilepsy, came into the public eye in 2013 when news broke that medical marijuana was able to do what other drugs could not: dramatically reduce her seizures. Now, new scientific research provides evidence that cannabis may be an effective treatment for a third of epilepsy patients who, like Charlotte, have a treatment-resistant form of the disease. Last month Orrin Devinsky, a neurologist at New York University Langone Medical Center, and his colleagues across multiple research centers published the results from the largest study to date of a cannabis-based drug for treatment-resistant epilepsy in The Lancet Neurology. The researchers treated 162 patients with an extract of 99 percent cannabidiol (CBD), a nonpsychoactive chemical in marijuana, and monitored them for 12 weeks. This treatment was given as an add-on to the patients’ existing medications and the trial was open-label (everyone knew what they were getting). The researchers reported the intervention reduced motor seizures at a rate similar to existing drugs (a median of 36.5 percent) and 2 percent of patients became completely seizure free. Additionally, 79 percent of patients reported adverse effects such as sleepiness, diarrhea and fatigue, although only 3 percent dropped out of the study due to adverse events. “I was a little surprised that the overall number of side effects was quite high but it seems like most of them were not enough that the patients had to come off the medication,” says Kevin Chapman, a neurology and pediatric professor at the University of Colorado School of Medicine who was not involved in the study. “I think that [this study] provides some good data to show that it's relatively safe—the adverse effects were mostly mild and [although] there were serious adverse effects, it's always hard to know in such a refractory population whether that would have occurred anyway.” © 2016 Scientific American,
The Chamorro people of the Pacific island of Guam know it as lytigo-bodig. For decades, they have been struck down by a mysterious illness that resembles the muscle-wasting disease amyotrophic lateral sclerosis (ALS), Parkinson’s disease and Alzheimer’s-like dementia. It now looks like we have a clue that could point to a way of slowing its development. Lytigo-bodig is a progressive disease. ALS symptoms arrive when people are in their mid-40s and early 50s. By the time they reach their 60s, they also have the shaking and lack of coordination that characterises Parkinson’s, before the cognitive problems associated with dementia also set in. “Initially they stumble a bit, but as their muscles wither, they need help with eating and going to the toilet, as well as having difficulty swallowing and breathing,” says Paul Cox of the Institute for Ethnomedicine in Wyoming. For a long time, a chemical called BMAA, found in the cycad seeds that the Chamorro grind up to make flour, has been suspected as the cause of the disease. The toxin builds up in the cyanobacteria that grow in the roots of cycad plants. It also accumulates in the tissue of seed-eating flying foxes, which the Chamorro hunt and eat. To see if they could confirm BMAA as the culprit, Cox fed fruit spiked with the toxin to vervet monkeys for 140 days. They estimated this was equivalent to the dose a typical islander might get over a lifetime. Although they didn’t show cognitive problems, the animals did develop brain abnormalities called tau tangles and deposits of amyloid plaque. The density and placement of these abnormalities were similar to those seen in the islanders. “The structure of the pathology is almost identical,” says Cox. “We were stunned.” © Copyright Reed Business Information Ltd.