Chapter 16. Psychopathology: Biological Basis of Behavior Disorders
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Jon Hamilton A new understanding of the brain's cerebellum could lead to new treatments for people with problems caused by some strokes, autism and even schizophrenia. That's because there's growing evidence that symptoms ranging from difficulty with abstract thinking to emotional instability to psychosis all have links to the cerebellum, says Jeremy Schmahmann, a professor of neurology at Harvard and Massachusetts General Hospital. "The cerebellum has all these functions we were previously unaware of," Schmahmann says. Scientists once thought the cerebellum's role was limited to balance and coordinating physical movements. In the past couple of decades, though, there has been growing evidence that it also plays a role in thinking and emotions. As described in an earlier post, some of the most compelling evidence has come from people like Jonathan Keleher, people born without a cerebellum. "I'm good at routine (activities) and (meeting) people," says Keleher, who is 33. He also has good long-term memory. What he's not good at is strategizing and abstract thinking. But remarkably, Keleher's abilities in these areas have improved dramatically over time. "I'm always working on how to better myself," he says. "And it's a continuous struggle." © 2015 NPR
By Nicholas Bakalar People sometimes take Valium or Ativan to relieve anxiety before surgery, but a new study suggests that these benzodiazepine drugs have little beneficial effect and may even delay recovery. Researchers studied 1,062 patients admitted to French hospitals for surgery requiring general anesthesia. A third took 2.5 milligrams of lorazepam (brand name Ativan), a third received a placebo, and a third were given no premedication. Patients completed questionnaires assessing anxiety, pain levels and quality of sleep before and a day after their operations, while researchers recorded their time to having ventilation tubes removed and to recovering full wakefulness. The study was published in JAMA. Lorazepam was associated with more postsurgery amnesia and a longer time to recover cognitive abilities. Quality of sleep was impaired in the lorazepam group, but not in the others. And ventilation tubes were kept in significantly longer in the lorazepam group. Pain scores did not differ between the lorazepam and the no-medication groups, but there was more pain in the group given the placebo. The lead author, Dr. Axel Maurice-Szamburski, an anesthesiologist at Timone Hospital in Marseille, cited recent surveys showing that benzodiazepines are widely prescribed before surgery. “But until now,” he added, “sedatives have not been evaluated from the patient’s point of view. It’s the patient who should be happy, not the doctor.” © 2015 The New York Times Company
Link ID: 20676 - Posted: 03.10.2015
Jon Hamilton Alzheimer's, Parkinson's and amyotrophic lateral sclerosis ravage the brain in very different ways. But they have at least one thing in common, says Corinne Lasmezas, a neuroscientist and professor at Scripps Research Institute, in Jupiter, Fla. Each spreads from brain cell to brain cell like an infection. "So if we could block this [process], that might prevent the diseases," Lasmezas says. It's an idea that's being embraced by a growing number of researchers these days, including Nobel laureate Dr. Stanley Prusiner, who first recognized in the 1980s the infectious nature of brain proteins that came to be called prions. But the idea that mad cow prions could cause disease in people has its origins in an epidemic of mad cow disease that occurred in Europe and the U.K. some 15 years ago. Back then, Lasmezas was a young researcher in France studying how mad cow, formally known as bovine spongiform encephalopathy, was transmitted. "At that time, nobody knew if this new disease in cows was actually transmissible to humans," she says. In 1996, Lasmezas published a study strongly suggesting that it was. "So that was my first great research discovery," she says. Prions, it turns out, become toxic to brain cells when folded into an abnormal shape. "This misfolded protein basically kills the neurons," Lasmezas says. © 2015 NPR
By CELIA WATSON SEUPEL Every year, nearly 40,000 Americans kill themselves. The majority are men, and most of them use guns. In fact, more than half of all gun deaths in the United States are suicides. Experts and laymen have long assumed that people who died by suicide will ultimately do it even if temporarily deterred. “People think if you’re really intent on dying, you’ll find a way,” said Cathy Barber, the director of the Means Matters campaign at Harvard Injury Control Research Center. Prevention, it follows, depends largely on identifying those likely to harm themselves and getting them into treatment. But a growing body of evidence challenges this view. Suicide can be a very impulsive act, especially among the young, and therefore difficult to predict. Its deadliness depends more upon the means than the determination of the suicide victim. Now many experts are calling for a reconsideration of suicide-prevention strategies. While mental health and substance abuse treatment must always be important components in treating suicidality, researchers like Ms. Barber are stressing another avenue: “means restriction.” Instead of treating individual risk, means restriction entails modifying the environment by removing the means by which people usually die by suicide. The world cannot be made suicide-proof, of course. But, these researchers argue, if the walkway over a bridge is fenced off, a struggling college freshman cannot throw herself over the side. If parents leave guns in a locked safe, a teenage son cannot shoot himself if he suddenly decides life is hopeless. With the focus on who dies by suicide, these experts say, not enough attention has been paid to restricting the means to do it — particularly access to guns. © 2015 The New York Times Company
Link ID: 20674 - Posted: 03.10.2015
By Rachel Rabkin Peachman Many women with a history of depression who take antidepressants assume that once they get pregnant, they should try to wean themselves off their meds to avoid negative side effects for the baby. A new large study published in the journal Pediatrics challenges one reason behind that assumption. The research found that taking selective serotonin reuptake inhibitors (the antidepressants also known as S.S.R.I.s) while pregnant does not increase the risk of asthma in the resulting babies. What is associated with an increased risk of asthma? According to this study and other research, untreated prenatal depression. “The mechanisms underlying the association of prenatal depression and asthma are unknown,” said Dr. Xiaoqin Liu, the lead author of the Pediatrics study and an epidemiologist at Aarhus University in Denmark. An association between prenatal depression and asthma does not mean that prenatal depression causes asthma. There could be other reasons for the correlation, genetic or environmental, or both. For example, people who live in dense, polluted urban areas could be at an increased risk of both asthma and depression. The researchers used Denmark’s national registries to evaluate all singleton babies born from 1996 to 2007, and identify the mothers who had a diagnosis of depression or had used antidepressants, or both, during pregnancy or one year beforehand. Using a statistical model, the study authors found that prenatal depression — with or without the use of antidepressants — was associated with a 25 percent increased risk of asthma in children as compared with children whose mothers did not have a record of depression. © 2015 The New York Times Company
Hannah Devlin, science correspondent Psychedelic drugs could prove to be highly effective treatments for depression and alcoholism, according to a study which has obtained the first brain scans of people under the influence of LSD. Early results from the trial, involving 20 people, are said to be “very promising” and add to existing evidence that psychoactive drugs could help reverse entrenched patterns of addictive or negative thinking. However, Prof David Nutt, who led the study, warned that patients are missing out on the potential benefits of such treatments due to prohibitive regulations on research into recreational drugs. Speaking at a briefing in London, the government’s former chief drugs adviser, said the restrictions amounted to “the worst censorship in the history of science”. After failing to secure conventional funding to complete the analysis of the latest study on LSD, Nutt and colleagues at Imperial College London, are now attempting to raise £25,000 through the crowd-funding site Walacea.com. “These drugs offer the greatest opportunity we have in mental health,” he said. “There’s little else on the horizon.” There has been a resurgence of medical interest in LSD and psilocybin, the active ingredient in magic mushrooms, after several recent trials produced encouraging results for conditions ranging from depression in cancer patients to post-traumatic stress disorder. © 2015 Guardian News and Media Limited
Zoe Cormier Data from population surveys in the United States challenge public fears that psychedelic drugs such as LSD can lead to psychosis and other mental-health conditions and to increased risk of suicide, two studies have found1, 2. In the first study, clinical psychologists Pål-Ørjan Johansen and Teri Suzanne Krebs, both at the Norwegian University of Science and Technology in Trondheim, scoured data from the US National Survey on Drug Use and Health (NSDUH), an annual random sample of the general population, and analysed answers from more than 135,000 people who took part in surveys from 2008 to 2011. Of those, 14% described themselves as having used at any point in their lives any of the three ‘classic’ psychedelics: LSD, psilocybin (the active ingredient in so-called magic mushrooms) and mescaline (found in the peyote and San Pedro cacti). The researchers found that individuals in this group were not at increased risk of developing 11 indicators of mental-health problems such as schizophrenia, psychosis, depression, anxiety disorders and suicide attempts. Their paper appears in the March issue of the Journal of Psychopharmacology1. The findings are likely to raise eyebrows. Fears that psychedelics can lead to psychosis date to the 1960s, with widespread reports of “acid casualties” in the mainstream news. But Krebs says that because psychotic disorders are relatively prevalent, affecting about one in 50 people, correlations can often be mistaken for causations. “Psychedelics are psychologically intense, and many people will blame anything that happens for the rest of their lives on a psychedelic experience.” © 2015 Nature Publishing Group,
By ROBERT PEAR WASHINGTON — Federal investigators say they have found evidence of widespread overuse of psychiatric drugs by older Americans with Alzheimer’s disease, and are recommending that Medicare officials take immediate action to reduce unnecessary prescriptions. The findings will be released Monday by the Government Accountability Office, an arm of Congress, and come as the Obama administration has already been working with nursing homes to reduce the inappropriate use of antipsychotic medications like Abilify, Risperdal, Zyprexa and clozapine. But in the study, investigators said officials also needed to focus on overuse of such drugs by people with dementia who live at home or in assisted living facilities. The Department of Health and Human Services “has taken little action” to reduce the use of antipsychotic drugs by older adults living outside nursing homes, the report said. Doctors sometimes prescribe antipsychotic drugs to calm patients with dementia who display disruptive behavior like hitting, yelling or screaming, the report said. Researchers said this was often the case in nursing homes that had inadequate numbers of employees. Dementia is most commonly associated with a decline in memory, but doctors say it can also cause changes in mood or personality and, at times, agitation or aggression. Experts have raised concern about the use of antipsychotic drugs to address behavioral symptoms of Alzheimer’s and other forms of dementia. The Food and Drug Administration says antipsychotic drugs are often associated with an increased risk of death when used to treat older adults with dementia who also have psychosis. © 2015 The New York Times Company
Anti-depressants are the most commonly-prescribed medication in the U.S., with one in 10 Americans currently taking pills like Zoloft and Lexapro to treat depression. But these pharmaceuticals are only fully effective roughly 30 percent of the time, and often come with troublesome side effects. In a controversial new paper published in the journal Neuroscience & Biobehavioral Reviews, psychologist Paul Andrews of McMaster University in Ontario argues that this failure of medication may be based in a misunderstanding of the underlying chemistry related to depression. Andrews surveyed 50 years' worth of research supporting the serotonin theory of depression, which suggests that the disease is caused by low levels of the "happiness" neurotransmitter, serotonin. But Andrews argues that depression may actually be caused by elevated levels of serotonin. And this fundamental misunderstanding may be responsible for inappropriate treatment: The most common form of antidepressants are selective serotonin re-uptake inhibitors (SSRIs), which operate by targeting serotonin receptors in the brain in an effort to amplify serotonin production. Currently, scientists are unable to measure precisely how the brain releases and uses serotonin, because it can't be safely observed in a human brain. But Andrews points to research on animals which suggests that serotonin might work just the opposite from what we've assumed. ©2015 TheHuffingtonPost.com, Inc.
Link ID: 20636 - Posted: 03.02.2015
Distinct changes in the immune systems of patients with ME or chronic fatigue syndrome have been found, say scientists. Increased levels of immune molecules called cytokines were found in people during the early stages of the disease, a Columbia University study reported. It said the findings could help improve diagnosis and treatments. UK experts said further refined research was now needed to confirm the results. People with ME (myalgic encephalopathy) or CFS (chronic fatigue syndrome) suffer from exhaustion that affects everyday life and does not go away with sleep or rest. They can also have muscle pain and difficulty concentrating. ME can also cause long-term illness and disability, although many people improve over time. It is estimated that around 250,000 people in the UK have the disease. Disease pattern The US research team, who published their findings in the journal Science Advances, tested blood samples from nearly 300 ME patients and around 350 healthy people. They found specific patterns of immune molecules in patients who had the disease for up to three years. These patients had higher levels of of cytokines, particularly one called interferon gamma, which has been linked to the fatigue that follows many viral infections. Healthy patients and those who had the disease for longer than three years did not show the same pattern. Lead author Dr Mady Hornig said this was down to the way viral infections could disrupt the immune system. "It appears that ME/CFS patients are flush with cytokines until around the three-year mark, at which point the immune system shows evidence of exhaustion and cytokine levels drop."
By ABIGAIL ZUGER, M.D. On an early summer night in 1944, on the wooded shoulder of a rural Massachusetts highway, a man in a rumpled brown suit wandered in the shadows. Whenever a car passed, he dropped to the ground and lay flat. His hair was matted, his face smeared with mud. He was a respectable Boston doctor on the lam, hungry, lost and ill. He was Mimi Baird’s father, Dr. Perry Baird, a Texas-born, Harvard-trained physician whose severe bipolar disease ultimately destroyed his life and scarred his family with the usual wide-ranging cruelties of mental illness. Dr. Baird vanished from Ms. Baird’s life when she was a little girl. She saw him once, briefly, when she was a teenager, then never again. He died in his mid-50s, in 1959. More than 30 years later, when Ms. Baird herself was in her 50s, a large package arrived on her doorstep and her father re-entered her world. The box contained a manuscript long forgotten in a relative’s garage, written in smudged pencil on onionskin paper, a memoir her father had composed of five terrible months in his life. The story began the very day Dr. Baird said goodbye to 5-year-old Mimi and her sister, and permanently left the household. Stunned and bereft all over again, Ms. Baird then spent two decades chasing down the rest of the story, talking to neighbors, colleagues and relatives about long-ago events and obtaining her father’s medical records. Now in her late 70s, a retired medical administrator, she has, with the help of a co-author, woven all this material into “He Wanted the Moon,” an extraordinary Möbius strip of a book. (Read an excerpt.) Its core is the full text of her father’s manuscript, deftly annotated and explained. Around it she layers the voices of caretakers, friends, relatives and medical authorities. Events are revisited and reframed, turned inside out, then right side up again. The book is autobiography, biography, science, history and literature all in one, as instructive as any textbook and utterly impossible to put down. © 2015 The New York Times Company
Link ID: 20600 - Posted: 02.24.2015
By Kate Baggaley A buildup of rare versions of genes that control the activity of nerve cells in the brain increases a person’s risk for bipolar disorder, researchers suggest in a paper posted online the week of February 16 in Proceedings of the National Academy of Sciences. “There are many different variants in many different genes that contribute to the genetic risk,” says coauthor Jared Roach, a geneticist at the Institute for Systems Biology in Seattle. “We think that most people with bipolar disorder will have inherited several of these…risk variants.” The bulk of a person’s risk for bipolar disorder comes from genetics, but only a quarter of that risk can be explained by common variations in genes. Roach’s team sequenced the genomes of 200 people from 41 families with a history of bipolar disorder. They then identified 164 rare forms of genes that show up more often in people with the condition. People with bipolar disorder had, on average, six of these rare forms, compared with just one, on average, found in their healthy relatives and the general population. The identified genes control the ability of ions, or charged particles, to enter or leave nerve cells, or neurons. This affects neurons’ ability to pass information through the brain. Some of the gene variants probably increase how much neurons fire while others decrease it, the researchers say. Future research will need to explain what role these brain changes play in bipolar disorder. Citations S.A. Ament et al. Rare variants in neuronal excitability genes influence risk for bipolar disorder. Proceedings of the National Academy of Sciences. Published online the week of February 16, 2015. doi:10.1073/pnas.1424958112. © Society for Science & the Public 2000 - 2015
|By Gary Stix Implantation of electrodes deep within the brain is now commonly performed for treatment of the neurological disorders Parkinson’s disease and essential tremor. But the use of deep-brain stimulation, as it is known, is expanding. It is now being assessed in as many as 200 patients for major depression—and is being considered for other disorders such as anorexia. Helen Mayberg, a neurologist from Emory University, has pioneered the use of imaging techniques to understand the functioning of different brain circuits to determine how to tailor various treatments for depression, including deep-brain stimulation, to a patient’s needs. Learn about her work below in “Deep-Brain Stimulation: A Decade of Progress with Helen Mayberg,” a Webinar put on by the Brain & Behavior Research Foundation. © 2015 Scientific American
Link ID: 20584 - Posted: 02.16.2015
By Rachel Ehrenberg SAN JOSE, Calif. — New moms suffering from postpartum depression change their activity on Facebook, suggesting that the social media site could help detect the onset of the baby blues. Many new parents share pictures and videos of their babies on Facebook and use the site to interact with friends they might be too busy to see in person. But compared with most typical new moms, those suffering from postpartum depression are less active on the social media site, Munmun De Choudhury of Georgia Tech reported February 14 at the annual meeting of the American Association for the Advancement of Science. She and her colleagues at Microsoft Research in Redmond, Wash., conducted an elaborate study that included a depression screening questionnaire, interviews and an analysis of Facebook activity and interactions of 165 mothers both before and after they had their babies. These women also tend to keep a stiff upper lip on the site, refraining from reporting on their emotional well-being and instead posting objective content geared toward getting feedback or advice on a specific matter, De Choudhury and her colleagues discovered. The scientists also found they could train a computer program to identify which moms had the blues. Such research might help with designing interventions, whereby moms could be warned that they might be sinking into depression and encouraged to reach out for social support or medical attention. M. De Choudhury. Online Social Dynamics and Emotional Wellbeing. American Association for the Advancement of Science Annual Meeting, San Jose, Calif., February 14, 2015. © Society for Science & the Public 2000 - 2015
Smoking potent cannabis was linked to 24% of new psychosis cases analysed in a study by King's College London. The research suggests the risk of psychosis is three times higher for users of potent "skunk-like" cannabis than for non-users. The study of 780 people was carried out by KCL's Institute of Psychiatry, Psychology and Neuroscience. A Home Office spokesman said the report underlines the reasons why cannabis is illegal. Scientists found the risk of psychosis was five times higher for those who use it every day compared with non-users. They also concluded the use of hash, a milder form of the drug, was not associated with increased risk of psychosis. Psychosis refers to delusions or hallucinations that can be present in certain psychiatric conditions such as schizophrenia and bipolar disorder. "Compared with those who had never tried cannabis, users of high potency skunk-like cannabis had a threefold increase in risk of psychosis,' said Dr Marta Di Forti, lead author on the research. She added: "The results show that psychosis risk in cannabis users depends on both the frequency of use and cannabis potency." Dr Di Forti told BBC Radio 4's Today programme that the availability of skunk-like cannabis was becoming more widespread. "In London, it's very difficult to find anything else," she said. "There were lots of reports from police across the UK saying we have become a great producer of skunk. And not only do we use it locally but we export, so this is a Made in England product." Someone suffering from psychosis would often be "extremely paranoid and become very suspicious" about the people around them, she added. She has called for "a clear public message" to cannabis users, comparable to medical advice on alcohol and tobacco. © 2015 BBC
By Jane E. Brody Bereavement — how one responds and adjusts to the death of a loved one — is a very individual matter. It is natural to experience a host of negative reactions in the weeks and months following the loss of a loved one: among them, sadness, difficulty sleeping, painful reminders of the person, difficulty enjoying activities once shared, even anger. Grief is a normal human reaction, not a disease, and there is no one right way to get through it. Most often, within six months of a death, survivors adjust and are more or less able to resume usual activities, experience joy, and remember their loved ones without intense pain. But sometimes, even when the loss is neither sudden nor unexpected, as is true in the majority of deaths in the United States, survivors close to the deceased can experience extremely disruptive grief reactions that persist far longer. In a report last month in The New England Journal of Medicine, Dr. M. Katherine Shear presents a composite portrait of what is known as complicated grief, an extreme, unrelenting reaction to loss that persists for more than six months and can result in a serious risk to health. She describes a 68-year-old widow who continued to be seriously impaired by grief four years after her husband died. The woman slept on the couch because she could not bear to sleep in the bed she had shared with him. She found it too painful to engage in activities they used to do together. She no longer ate regular meals because preparing them was a too-distressing reminder of her loss. And she remained alternately angry with the medical staff who cared for him and with herself for not recognizing his illness earlier. Symptoms of complicated grief commonly include intense yearning, longing or emotional pain; frequent preoccupying, intrusive thoughts and memories of the person lost; a feeling of disbelief or inability to accept the loss; and difficulty imagining a meaningful life without that person. © 2015 The New York Times Company
By David Tuller The Institute of Medicine on Tuesday proposed a new name and new diagnostic criteria for the condition that many still call chronic fatigue syndrome. Experts generally agree that the disease has a physical basis, but they have struggled for decades to characterize its symptoms. The new report may help improve diagnosis, but the recommendations are unlikely to end the long, contentious debate over who has the condition and what may be causing it. An institute panel recommended that the illness be renamed “systemic exertion intolerance disease,” a term that reflects what patients, clinicians and researchers all agree is a core symptom: a sustained depletion of energy after minimal activity, called postexertional malaise. The new name “really describes much more directly the key feature of the illness, which is the inability to tolerate both physical and cognitive exertion,” said Dr. Peter Rowe, a member of the panel and a pediatrician at Johns Hopkins who treats children with the condition. An alternate name for the illness, myalgic encephalomyelitis, meaning “brain and spinal cord inflammation with muscle pain,” was coined decades ago. Many experts now refer to the condition as M.E./C.F.S. About one million people in the United States are believed to have the syndrome. Many say they have been accused of imagining or exaggerating their symptoms, and many doctors have long viewed it as a psychological illness. The authors urged that doctors take patients’ physical complaints seriously. “This is not a figment of their imagination,” said Dr. Ellen Wright Clayton, the chairwoman of the Institute of Medicine panel and a professor of pediatrics and law at Vanderbilt University. Patients attribute much of their mistreatment to the name “chronic fatigue syndrome,” chosen by the Centers for Disease Control in 1988. © 2015 The New York Times Company
Link ID: 20573 - Posted: 02.13.2015
By ALAN SCHWARZ High numbers of students are beginning college having felt depressed and overwhelmed during the previous year, according to an annual survey released on Thursday, reinforcing some experts’ concern about the emotional health of college freshmen. The survey of more than 150,000 students nationwide, “The American Freshman: National Norms Fall 2014,” found that 9.5 percent of respondents had frequently “felt depressed” during the past year, a significant rise over the 6.1 percent reported five years ago. Those who “felt overwhelmed” by schoolwork and other commitments rose to 34.6 percent from 27.1 percent. Conducted by the Cooperative Institutional Research Program at the University of California, Los Angeles’s Higher Education Research Institute for almost 50 years, the survey assesses hundreds of matters ranging from political views to exercise habits. It is considered one of the most comprehensive snapshots of trends among recent high school seniors and is of particular interest to people involved in mental well-being. “It’s a public health issue,” said Dr. Anthony L. Rostain, a psychiatrist and co-chairman of a University of Pennsylvania task force on students’ emotional health. “We’re expecting more of students: There’s a sense of having to compete in a global economy, and they think they have to be on top of their game all the time. It’s no wonder they feel overwhelmed.” Other survey results indicated that students were spending more time on academics and socializing less — trends that would normally be lauded. But the lead author of the study, Kevin Eagan, cautioned that the shift could result in higher levels of stress. © 2015 The New York Times Company
By Janice Neumann (Reuters Health) - Moderate-intensity exercise, or even just walking, can improve quality of life for depressed middle-aged women, a large Australian study suggests. Women who averaged 150 minutes of moderate exercise (golf, tennis, aerobics classes, swimming, or line-dancing) or 200 minutes of walking every week had more energy, socialized more, felt better emotionally, and weren't as limited by their depression when researchers followed up after three years. They also had less pain and did better physically, although the psychological benefit was greater. With depression so prevalent, "there is an urgent need" to identify treatments, including non-medical options that people can do themselves, said Kristiann Heesch, who led the study. Heesch, senior lecturer at Queensland University of Technology, and her colleagues point out in a January 13 online article in the American Journal of Preventive Medicine that depression is expected to be the second-leading cause of global disease by 2030 and the leading cause in high-income countries. One in 10 U.S. adults suffers from depression, according to the Centers for Disease Control and Prevention. Women are 70% more likely to be depressed at some point in their lives than men, according to the National Institute of Mental Health. In previous research, Heesch found that exercise and walking could boost physical and emotional health in women who are not depressed. © 2015 Scientific American
Link ID: 20536 - Posted: 01.31.2015
by Jessica Hamzelou WHAT doesn't kill you makes you stronger, at least when it comes to stress and immune cells. Mice that received a cocktail of immune cells from bullied mice appeared to experience a mood boost. The unexpected discovery may have implications for treating depression. We know that prolonged bouts of stress take their toll on the immune system. That leaves us susceptible to illness, which in some cases can lead to depression. Most research on the link between immune health and mood has focused on the innate branch of the immune system – the cells that mount the first response to pathogens, says Miles Herkenham at the National Institutes of Health in Bethesda, Maryland. His team wondered if there might also be a role for the adaptive branch of the immune system, which "learns" about a pathogen in order to respond rapidly the next time it appears. To find out, the team introduced an aggressive competitor mouse into the cages of male mice. "These mice are like bullies," says Herkenham. Two weeks later, the bullied mice seemed depressed: they cowered in dark corners and seemed uninterested in the scent of a female. The team extracted their adaptive immune cells and injected them into another set of mice bred to lack these cells. This meant that the recipient mice essentially acquired the adaptive immune system of the bullied ones. © Copyright Reed Business Information Ltd.