Chapter 12. Psychopathology: Biological Basis of Behavioral Disorders
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
by Sara Reardon As suicide rates climb steeply in the US a growing number of psychiatrists are arguing that suicidal behaviour should be considered as a disease in its own right, rather than as a behaviour resulting from a mood disorder. They base their argument on mounting evidence showing that the brains of people who have committed suicide have striking similarities, quite distinct from what is seen in the brains of people who have similar mood disorders but who died of natural causes. Suicide also tends to be more common in some families, suggesting there may be genetic and other biological factors in play. What's more, most people with mood disorders never attempt to kill themselves, and about 10 per cent of suicides have no history of mental disease. The idea of classifying suicidal tendencies as a disease is being taken seriously. The team behind the fifth edition of the Diagnostic Standards Manual (DSM-5) – the newest version of psychiatry's "bible", released at the American Psychiatric Association's meeting in San Francisco this week – considered a proposal to have "suicide behaviour disorder" listed as a distinct diagnosis. It was ultimately put on probation: put into a list of topics deemed to require further research for possible inclusion in future DSM revisions. Another argument for linking suicidal people together under a single diagnosis is that it could spur research into the neurological and genetic factors they have in common. This could allow psychiatrists to better predict someone's suicide risk, and even lead to treatments that stop suicidal feelings. © Copyright Reed Business Information Ltd.
Keyword: Depression; Aggression
Link ID: 18165 - Posted: 05.18.2013
20:00 13 May 2013 by Douglas Heaven Genes in cells throughout the body switch on and off throughout the day in a coordinated way. Or at least they should. In people with clinical depression, genes in their brain tissues appear to be significantly out of sync – a finding that could lead to new treatments for the condition. We know from previous studies that genes in cells elsewhere, such as the skin, follow a 24-hour cycle of activity. But identifying patterns of genetic activity in a living brain isn't easy to do. "We always assumed we would have a clock [in our brain]," says Huda Akil at the University of Michigan in Ann Arbor. "But it had never been shown before." Akil and her colleagues examined the brains of 55 people with a known time of death, looking at around 12,000 genes in tissues from six brain regions. By matching the time of death with molecular signs of genetic activity – whether each gene was actively expressing itself or not – the team identified hundreds of genes that follow a daily cycle. Sudden death Akil says it was important to look at the brains of individuals who had died suddenly – through a heart attack or car accident, for example. Slower deaths can cause dramatic changes in the brain that would have obscured what they were looking for, but sudden death freezes the genetic activity. "We can capture an instant," she says. © Copyright Reed Business Information Ltd.
Keyword: Depression; Aggression
Link ID: 18158 - Posted: 05.14.2013
By Samyukta Mullangi A recent article in NYTimes [1] declared that the rising rate of suicides among our baby boomer generation now made suicides, by raw numbers alone, a bigger killer than motor vehicle accidents! Researchers quoted within the article pointed to complex reasons like the economic downturn over the past decade, the widespread availability of opioid drugs like oxycodone, and changes in marriage, social isolation and family roles. Then I scrolled down, as I always do, to peruse some of the readers’ comments, and that’s when I paused. I suppose in hindsight that I had expected readers to exclaim at the shocking statistics (suicide rates now stand at 27.3 per 100,000 for middle aged men, 8.1 per 100,000 for women), or lament over personal stories of relatives or friends who took their own lives. While I certainly saw a few such comments, I was amazed to discover the number of readers who were sympathetic to the idea of suicide. “Molly” wrote “Why is suicide usually looked upon as a desperate and forbidden act? Can’t we accept that in addition to poverty, loneliness, alienation, ill health, life in world [sic] that is sometimes personally pointless means that death is a relief? I believe the right to die, in a time and place (and wishfully peacefully without violence) is a basic human right.” This post was ‘recommended’ by 351 other readers at the time of this essay being written. © 2013 Scientific American
Keyword: Depression; Aggression
Link ID: 18157 - Posted: 05.14.2013
Pregnant mothers’ exposure to the flu was associated with a nearly fourfold increased risk that their child would develop bipolar disorder in adulthood, in a study funded by the National Institutes of Health. The findings add to mounting evidence of possible shared underlying causes and illness processes with schizophrenia, which some studies have also linked to prenatal exposure to influenza. “Prospective mothers should take common sense preventive measures, such as getting flu shots prior to and in the early stages of pregnancy and avoiding contact with people who are symptomatic,” said Alan Brown, M.D., M.P.H, of Columbia University and New York State Psychiatric Institute, a grantee of the NIH’s National Institute of Mental Health (NIMH). “In spite of public health recommendations, only a relatively small fraction of such women get immunized. The weight of evidence now suggests that benefits of the vaccine likely outweigh any possible risk to the mother or newborn.” Brown and colleagues reported their findings online May 8, 2013 in JAMA Psychiatry. Although there have been hints of a maternal influenza/bipolar disorder connection, the new study is the first to prospectively follow families in the same HMO, using physician-based diagnoses and structured standardized psychiatric measures. Access to unique Kaiser-Permanente, county and Child Health and Development Study External Web Site Policy databases made it possible to include more cases with detailed maternal flu exposure information than in previous studies.
Keyword: Schizophrenia; Aggression
Link ID: 18154 - Posted: 05.14.2013
Heidi Ledford Nassir Ghaemi, director of the Mood Disorders Program at Tufts Medical Center in Boston, Massachusetts, has felt shackled by the Diagnostic and Statistical Manual of Mental Disorders (DSM), often called the bible of psychiatry. Some of his depressed patients occasionally show manic behaviour but do not fulfil the DSM’s criteria for a diagnosis of bipolar disorder. Ghaemi is interested in whether such patients might respond better to drugs for bipolar disorder than for depression. But his colleagues warned him against straying from the DSM when he applied for funding at the US National Institute of Mental Health (NIMH), because peer reviewers tended to insist on research that hewed to DSM categories. Ghaemi held off from applying. If NIMH director Thomas Insel has his way, Ghaemi and other mental-health researchers will no longer feel the weight of the DSM. “NIMH will be re-orienting its research away from DSM categories,” Insel wrote in a blog entry on 29 April. The latest edition, the DSM-5, will be unveiled on 22 May at the annual meeting of the American Psychiatric Association in San Francisco, California. Like many psychiatrists, Insel questions whether the DSM’s categories accurately reflect the way the brain works. He is pushing a project that aims to create a new framework that classifies mental-health disorders according to their biological roots. “Going forward, we will be supporting research projects that look across current categories — or sub-divide current categories — to begin to develop a better system,” Insel wrote. The blog post made waves in the media and rattled some psychiatric clinicians and researchers. But Insel says that he has been talking about the issue since 2008. “The word was just still not out there,” he says. Insel says that he has increasingly received complaints from grant applicants who have tried to follow his guidance, only to be shot down by peer reviewers for eschewing DSM scripture. © 2013 Nature Publishing Group
Keyword: Schizophrenia; Aggression
Link ID: 18144 - Posted: 05.11.2013
by Claudia M Gold It seems that the National Institute of Mental Health (NIMH) may have dealt a death blow to the recently published Diagnostic and Statistical Manual of Mental Disorders (DSM 5) when the organization declared they would no longer fund research based on the DSM system of diagnosis. The views of NIMH director Thomas Insel were referenced in the recent New York Times article on the subject. His goal was to reshape the direction of psychiatric research to focus on biology, genetics and neuroscience so that scientists can define disorders by their causes, rather than their symptoms. I am no fan of the DSM system, which reduces complex experience to lists of symptoms; focusing on the "what" rather than the "why." However, the NIMH model has limits as well. There seems to be a wish to study mental illness in the same way we study cancer or diabetes. While I certainly have great respect for the complexity of the pancreas, or the process of malignant transformation of cells, trying to understand the brain/mind in an analogous way seems to be an unnecessary and even undesirable reduction of human experience. What is missing from both paradigms is recognition of the relational and historical context of being human. Fortunately there seems to be awareness that neither paradigm is complete. The Times article goes on to say: Dr. Insel is one of a growing number of scientists who think that the field needs an entirely new paradigm for understanding mental disorders, though neither he nor anyone else knows exactly what it will look like. © 2013 NY Times Co.
Keyword: Schizophrenia; Aggression
Link ID: 18143 - Posted: 05.11.2013
By NICHOLAS BAKALAR Two studies have found that depression and the use of certain antidepressants are both associated with increased risk for Clostridium difficile infection, an increasingly common cause of diarrhea that in the worst cases can be fatal. Researchers studied 16,781 men and women, average age 68, using hospital records and interviews to record cases of the infection, often called C. diff, and diagnoses of depression. The interviews were conducted biennially from 1991 to 2007 to gather self-reports of feelings of sadness and other emotional problems. There were 404 cases of C. difficile infection. After adjusting for other variables, the researchers found that the risk of C. diff infection among people with a history of depression or depressive symptoms was 36 to 47 percent greater than among people without depression. A second study, involving 4,047 hospitalized patients, average age 58, found a similar association of infection with depression. In addition, it found an association of some antidepressants — Remeron, Prozac and trazodone — with C. diff infection. There was no association with other antidepressants. “We have known for a long time that depression is associated with changes in the gastrointestinal system,” said the lead author, Mary A.M. Rogers, a research assistant professor at the University of Michigan, “and this interaction between the brain and the gut deserves more study.” Both reports appeared in the journal BMC Medicine. Copyright 2013 The New York Times Company
Keyword: Depression; Aggression
Link ID: 18136 - Posted: 05.09.2013
By James Gallagher Health and science reporter, BBC News Flu during pregnancy may increase the risk of the unborn child developing bipolar disorder later in life, research suggests. A study of 814 expectant women, published in JAMA Psychiatry, showed that infection made bipolar four times more likely. The overall risk remained low, but it echoes similar findings linking flu and schizophrenia. Experts said the risks were small and women should not worry. Bipolar leads to intense mood swings, which can last months, ranging from depression and despair to manic feelings of joy, overactivity and loss of inhibitions. Researchers at the Columbia University Medical Center identified a link between the condition, often diagnosed during late teens and twenties, and experiences in the womb. In their study looking at people born in the early 1960s, bipolar disorder was nearly four times as common in people whose mothers caught flu during pregnancy. The condition affects about one in 100 people. The lead researcher, Prof Alan Brown, estimated that influenza infection during pregnancy could lead to a 3-4% chance of bipolar disorder in the resulting children. However, in the vast majority of cases of bipolar disorder there would no history of flu. BBC © 2013
Keyword: Schizophrenia; Aggression
Link ID: 18135 - Posted: 05.09.2013
By Ben Thomas Horror isn’t the only film genre that specializes in dread. War movies like Apocalypse Now, sci-fi mysteries like Brazil and Blade Runner, and dramas like Melancholia and Requiem for a Dream all masterfully evoke a less violent, more subtle and pervasive sense that something is unwell with the world – that somewhere along the line, something went deeply wrong and now normality itself is unraveling before our eyes. The director David Lynch has arguably built his entire career on directing these kinds of films. In Lynch’s universe, even the most banal moments are still somehow suffused with unnerving suspense. In films like Blue Velvet and Mulholland Drive, disturbing surprises erupt into scene after scene of buried tension, until every ordinary conversation feels like a trap waiting to spring. And then there’s the infamous Eraserhead, where family life itself is transformed into an onslaught of surreal and nauseating images. It’s hard to come away from these movies without feeling that a little of Lynch’s unease has rubbed off on you. So when a team of researchers at the University of British Columbia set out to describe and treat an ancient biological alarm system buried deep within the human brain, they turned to Lynch’s films as an analogy for – and a set of examples of – the feeling of omnipresent yet maddeningly vague “wrongness” that seems to underlie many anxiety disorders. © 2013 Scientific American
Keyword: Emotions
Link ID: 18134 - Posted: 05.09.2013
By PAM BELLUCK and BENEDICT CAREY Just weeks before the long-awaited publication of a new edition of the so-called bible of mental disorders, the federal government’s most prominent psychiatric expert has said the book suffers from a scientific “lack of validity.” The expert, Dr. Thomas R. Insel, director of the National Institute of Mental Health, said in an interview Monday that his goal was to reshape the direction of psychiatric research to focus on biology, genetics and neuroscience so that scientists can define disorders by their causes, rather than their symptoms. While the Diagnostic and Statistical Manual of Mental Disorders, or D.S.M., is the best tool now available for clinicians treating patients and should not be tossed out, he said, it does not reflect the complexity of many disorders, and its way of categorizing mental illnesses should not guide research. “As long as the research community takes the D.S.M. to be a bible, we’ll never make progress,” Dr. Insel said, adding, “People think that everything has to match D.S.M. criteria, but you know what? Biology never read that book.” The revision, known as the D.S.M.-5 and the first since 1994, has stirred unprecedented questioning from the public, patient groups and, most fundamentally, senior figures in psychiatry who have challenged not only decisions about specific diagnoses but the scientific basis of the entire enterprise. Basic research into the biology of mental disorders and treatment has stalled, they say, confounded by the labyrinth of the brain. © 2013 The New York Times Company
Keyword: Schizophrenia; Aggression
Link ID: 18128 - Posted: 05.07.2013
by Emily Underwood The fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5)—slated for release this month—has lost a major customer before even going to print. Thomas Insel, director of the National Institute of Mental Health (NIMH), declared last week on his blog that the institution will no longer use the manual to guide its research. Instead, NIMH is working on a long-term plan to develop new diagnostic criteria and treatments based on genetic, physiologic, and cognitive data rather than symptoms alone. Insel's pronouncement is the most recent hit in a long barrage of criticism that has rained down upon the latest DSM revision process since it began over a decade ago. "While DSM has been described as a 'Bible' for the field," he wrote, "it is, at best, a dictionary, creating a set of labels and defining each." Although the manual's strength has been to standardize these labels, he wrote, "[t]he weakness is its lack of validity," and "[p]atients with mental disorders deserve better." Although Insel's blog was reported as a "bombshell," and "potentially seismic," NIMH's decision to scrap the DSM criteria has been public for several years, says Bruce Cuthbert, director of NIMH's Division of Adult Translational Research and Treatment Development. In 2010, the agency began to steer researchers away from the traditional categories of DSM by posting new guidance for grant proposals in five broad areas. Rather than grouping disorders such as schizophrenia and depression by symptom, the new categories focus on basic neural circuits and cognitive functions, such as those for reward, arousal, and attachment. © 2010 American Association for the Advancement of Science.
Keyword: Schizophrenia; Aggression
Link ID: 18127 - Posted: 05.07.2013
By John Horgan What is mental illness? Schizophrenia? Autism? Bipolar disorder? Depression? Since the 1950s, the profession of psychiatry has attempted to provide definitive answers to these questions in the Diagnostic and Statistical Manual of Mental Disorders. Often called The Bible of psychiatry, the DSM serves as the ultimate authority for diagnosis, treatment and insurance coverage of mental illness. Now, in a move sure to rock psychiatry, psychology and other fields that address mental illness, the director of the National Institutes of Mental Health has announced that the federal agency–which provides grants for research on mental illness–will be “re-orienting its research away from DSM categories.” Thomas Insel’s statement comes just weeks before the scheduled publication of the DSM-V, the fifth edition of the Diagnostic and Statistical Manual. Insel writes: “While DSM has been described as a ‘Bible’ for the field, it is, at best, a dictionary, creating a set of labels and defining each. The strength of each of the editions of DSM has been ‘reliability’–each edition has ensured that clinicians use the same terms in the same ways. The weakness is its lack of validity. Unlike our definitions of ischemic heart disease, lymphoma, or AIDS, the DSM diagnoses are based on a consensus about clusters of clinical symptoms, not any objective laboratory measure. In the rest of medicine, this would be equivalent to creating diagnostic systems based on the nature of chest pain or the quality of fever. Indeed, symptom-based diagnosis, once common in other areas of medicine, has been largely replaced in the past half century as we have understood that symptoms alone rarely indicate the best choice of treatment. Patients with mental disorders deserve better.” © 2013 Scientific American
Keyword: Schizophrenia; Aggression
Link ID: 18120 - Posted: 05.06.2013
By TARA PARKER-POPE Suicide rates among middle-aged Americans have risen sharply in the past decade, prompting concern that a generation of baby boomers who have faced years of economic worry and easy access to prescription painkillers may be particularly vulnerable to self-inflicted harm. More people now die of suicide than in car accidents, according to the Centers for Disease Control and Prevention, which published the findings in Friday’s issue of its Morbidity and Mortality Weekly Report. In 2010 there were 33,687 deaths from motor vehicle crashes and 38,364 suicides. Suicide has typically been viewed as a problem of teenagers and the elderly, and the surge in suicide rates among middle-aged Americans is surprising. From 1999 to 2010, the suicide rate among Americans ages 35 to 64 rose by nearly 30 percent, to 17.6 deaths per 100,000 people, up from 13.7. Although suicide rates are growing among both middle-aged men and women, far more men take their own lives. The suicide rate for middle-aged men was 27.3 deaths per 100,000, while for women it was 8.1 deaths per 100,000. The most pronounced increases were seen among men in their 50s, a group in which suicide rates jumped by nearly 50 percent, to about 30 per 100,000. For women, the largest increase was seen in those ages 60 to 64, among whom rates increased by nearly 60 percent, to 7.0 per 100,000. Suicide rates can be difficult to interpret because of variations in the way local officials report causes of death. But C.D.C. and academic researchers said they were confident that the data documented an actual increase in deaths by suicide and not a statistical anomaly. While reporting of suicides is not always consistent around the country, the current numbers are, if anything, too low. © 2013 The New York Times Company
Keyword: Depression; Aggression
Link ID: 18118 - Posted: 05.04.2013
by Andy Coghlan and Sara Reardon The world's biggest mental health research institute is abandoning the new version of psychiatry's "bible" – the Diagnostic and Statistical Manual of Mental Disorders, questioning its validity and stating that "patients with mental disorders deserve better". This bombshell comes just weeks before the publication of the fifth revision of the manual, called DSM-5. On 29 April, Thomas Insel, director of the US National Institute of Mental Health (NIMH), advocated a major shift away from categorising diseases such as bipolar disorder and schizophrenia according to a person's symptoms. Instead, Insel wants mental disorders to be diagnosed more objectively using genetics, brain scans that show abnormal patterns of activity and cognitive testing. This would mean abandoning the manual published by the American Psychiatric Association that has been the mainstay of psychiatric research for 60 years. The DSM has been embroiled in controversy for a number of years. Critics have said that it has outlasted its usefulness, has turned complaints that are not truly illnesses into medical conditions, and has been unduly influenced by pharmaceutical companies looking for new markets for their drugs. There have also been complaints that widened definitions of several disorder have led to over-diagnosis of conditions such as bipolar disorder and attention deficit hyperactivity disorder. Now, Insel has said in a blog post published by the NIMH that he wants a complete shift to diagnoses based on science not symptoms. © Copyright Reed Business Information Ltd.
Keyword: Depression; Aggression
Link ID: 18117 - Posted: 05.04.2013
The short answer is no. But your question gets to the heart of an important problem that we have in this country: that all medications are approved by the Food and Drug Administration on the basis of relatively short-term studies, even though many are used long-term for medical and psychiatric disorders that are chronic, if not lifelong. The F.D.A. approves antidepressants like selective serotonin re-uptake inhibitors, or S.S.R.I.’s, if the drug beats a placebo in two randomized clinical trials that typically last 4 to 12 weeks and involve a few hundred patients. Longer-term maintenance studies, usually lasting one to two years, indicate that S.S.R.I.’s do not cause any serious harm, though they have plenty of side effects, like weight gain and sexual dysfunction. Once a drug hits the market, we have only a voluntary system of reporting adverse effects in the United States; there are no systematic long-term studies of any drug lasting 10 or more years. Still, S.S.R.I.’s have been used since the late 1980s and given to more than 40 million Americans, so it’s reasonable to say that if these drugs caused any significant toxic effects, we would have seen many such reports. Instead, we have some anecdotal reports claiming a wide range of S.S.R.I.-related toxicity, but one cannot know from these reports whether the symptoms are related to S.S.R.I. use or to medical illnesses that happen to develop over time in people taking these drugs. Copyright 2013 The New York Times Company
Keyword: Depression
Link ID: 18116 - Posted: 05.04.2013
By Ferris Jabr This month the American Psychiatric Association (APA) will publish the fifth edition of its guidebook for clinicians, the Diagnostic and Statistical Manual of Mental Disorders, or DSM-5. Researchers around the world have eagerly anticipated the new manual, which, in typical fashion, took around 14 years to revise. The DSM describes the symptoms of more than 300 officially recognized mental illnesses—depression, bipolar disorder, schizophrenia and others—helping counselors, psychiatrists and general care practitioners diagnose their patients. Yet it has a fundamental flaw: it says nothing about the biological underpinnings of mental disorders. In the past, that shortcoming reflected the science. For most of the DSM's history, investigators have not had a detailed understanding of what causes mental illness. That excuse is no longer valid. Neuroscientists now understand some of the ways that brain circuits for memory, emotion and attention malfunction in various mental disorders. Since 2009 clinical psychologist Bruce Cuthbert and his team at the National Institute of Mental Health have been constructing a classification system based on recent research, which is revealing how the structure and activity of a mentally ill brain differs from that of a healthy one. The new framework will not replace the DSM, which is too important to discard, Cuthbert says. Rather he and his colleagues hope that future versions of the guide will incorporate information about the biology of mental illness to better distinguish one disorder from another. Cuthbert, whose project may receive additional funding from the Obama administration's planned Brain Activity Map initiative, is encouraging researchers to study basic cognitive and biological processes implicated in many types of mental illness. Some scientists might explore how and why the neural circuits that detect threats and store fearful memories sometimes behave in unusual ways after traumatic events—the kinds of changes that are partially responsible for post-traumatic stress disorder. Others may investigate the neurobiology of hallucinations, disruptions in circadian rhythms, or precisely how drug addiction rewires the brain. © 2013 Scientific American
Keyword: Schizophrenia; Aggression
Link ID: 18101 - Posted: 05.01.2013
By Scicurious Say you are out on a camping trip with some friends. You’re in the woods, the tents are up, the beer is out, the sun is down, the campfire is starting up. As you sit there, you hear the campfire crackling loudly. To most people, the crackling of the campfire is just that: a campfire. Nothing threatening at all. But for someone with a severe anxiety disorder such as post-traumatic stress disorder (PTSD), the crackling of the campfire may be associated with terrible memories, a huge conflagration during house to house fighting or a house fire that destroyed all they loved, causing them horrible distress and terrible anxiety. A campfire during a camping trip and the horrible things they endured are entirely dissimilar things, but in severe anxiety disorders, that makes no difference at all. No, this post is not about whether or not anxiety disorders are being over diagnosed. Rather, it’s about how over-generalization within the brain might influence the development of anxiety disorders. What is the difference between a house fire and a campfire? How does your brain know? It’s the idea of pattern separation, an idea that the authors of this review believe could be incredibly important in treating some types of anxiety disorders. Pattern separation is one of the many actions of the hippocampus, the large, curved area in the interior of the brain which is thought to play a role in things like memory and in disorders such as anxiety and depression. Pattern separation was originally observed related to memory, but the authors of this review propose that it may also relate to things like anxiety. © 2013 Scientific American
Keyword: Stress
Link ID: 18089 - Posted: 04.29.2013
By LINDA LOGAN The last time I saw my old self, I was 27 years old and living in Boston. I was doing well in graduate school, had a tight circle of friends and was a prolific creative writer. Married to my high-school sweetheart, I had just had my first child. Back then, my best times were twirling my baby girl under the gloaming sky on a Florida beach and flopping on the bed with my husband — feet propped against the wall — and talking. The future seemed wide open. I don’t think there is a particular point at which I can say I became depressed. My illness was insidious, gradual and inexorable. I had a preview of depression in high school, when I spent a couple of years wearing all black, rimming my eyes in kohl and sliding against the walls in the hallways, hoping that no one would notice me. But back then I didn’t think it was a very serious problem. The hormonal chaos of having three children in five years, the pressure of working on a Ph.D. dissertation and a genetic predisposition for a mood disorder took me to a place of darkness I hadn’t experienced before. Of course, I didn’t recognize that right away. Denial is a gauze; willful denial, an opiate. Everyone seemed in league with my delusion. I was just overwhelmed, my family would say. I should get more help with the kids, put off my Ph.D. When I told other young mothers about my bone-wearying fatigue, they rolled their eyes knowingly and mumbled, “Right.” But what they didn’t realize was that I could scarcely push the stroller to the park, barely summon the breath to ask the store clerk, “Where are the Pampers?” I went from doctor to doctor, looking for the cause. Lab tests for anemia, low blood sugar and hypothyroidism were all negative. © 2013 The New York Times Company
Keyword: Schizophrenia
Link ID: 18085 - Posted: 04.28.2013
By David Levine Sleep deprivation is a quick and efficient way to treat depression. It works 60 to 70 percent of the time—far better than existing drugs—but the mood boost usually lasts only until the patient falls asleep. As an ongoing treatment, sleep deprivation is impractical, but researchers have been studying the phenomenon in an effort to uncover the cellular mechanisms behind depression and remission. Now a team at Tufts University has pinpointed glia as the key players. The researchers previously found that astrocytes, a star-shaped type of glial cell, regulate the brain chemicals involved in sleepiness. During our waking hours, astrocytes continuously release the neurotransmitter adenosine, which builds up in the brain and causes “sleep pressure,” the feeling of sleepiness and its related memory and attention impairments. The neurotransmitter causes this pressure by binding to adenosine receptors on the outside of neurons like a key fitting into a lock. As more adenosine builds up, more receptors are triggered, and the urge to sleep gets stronger. In the new study, published online January 15 in the journal Translational Psychiatry, the scientists investigated whether this process is responsible for the antidepressant effects of sleep deprivation. Mice with depressivelike symptoms were administered three doses of a compound that triggers adenosine receptors, thus mimicking sleep deprivation. Although the mice continued to sleep normally, after 12 hours they showed a rapid improvement in mood and behavior, which lasted for 48 hours. © 2013 Scientific American
Keyword: Depression; Aggression
Link ID: 18083 - Posted: 04.27.2013
Sunanda Creagh, The Conversation Testosterone may trigger a brain chemical process linked to schizophrenia but the same sex hormone can also improve cognitive thinking skills in men with the disorder, two new studies show. Scientists have long suspected testosterone plays an important role in schizophrenia, which affects more men than women. Men are also more likely to develop psychosis in adolescence, previous research has shown. A new study on lab rodents by researchers from Neuroscience Research Australia analysed the impact increased testosterone had on levels of dopamine, a brain chemical linked to psychotic symptoms of schizophrenia. The researchers found that testosterone boosted dopamine sensitivity in adolescent male rodents. “From these rodent studies, we hypothesise that adolescent increases in circulating testosterone may be a driver of increased dopamine activity in the brains of individuals susceptible to psychosis and schizophrenia,” said senior Neuroscience Research Australia researcher and author of the study, Dr Tertia Purves-Tyson, who is presenting her work at the International Congress on Schizophrenia Research in Florida. Dr Philip Mitchell, Scientia Professor and Head of the School of Psychiatry at the University of NSW, said the research was very interesting. © 2013 ScienceAlert Pty Ltd.
Keyword: Schizophrenia; Aggression
Link ID: 18076 - Posted: 04.27.2013




