For six years, psychiatrists thought they had found a genetic clue as to what makes some people more prone to depression when they’re hit with an emotional blow: a single gene. A 2003 study created a sensation among scientists and the public because it offered the first specific, plausible explanation of why some people bounce back after a stressful life event while others plunge into lasting despair [The New York Times]. But now a broader analysis of 14 studies has found no link between the gene and the risk of depression, and researchers argue that the 2003 findings were prematurely heralded as a breakthrough. “I think what happened is that people who’d been working in this field for so long were desperate to have any solid finding” [The New York Times], says Kathleen R. Merikangas, one of the authors of the new study.
The so-called “depression gene” that researchers focused on in the 2003 study helps regulate levels of serotonin, a brain chemical that plays a major role in depression and is a key target of antidepressant drugs. Researchers … found from a long-term study of 847 people in New Zealand that those with a short version, or allele, of the serotonin transporter gene were more likely to become depressed by adverse life events than were those with only long alleles [ScienceNOW Daily News].
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Tumors may physically trigger depression by producing chemicals that induce negative mood swings, according to a new study. The research, conducted in rats, allowed for the isolation of “just the physiological effects of the tumors from the psychological effects…. The tumors themselves are sufficient to induce depression” [The Scientist], says lead researcher Leah Pyter.
The new study, published in the Proceedings of the National Academy of Sciences, showed first that rats who had cancer exhibited several behavioral symptoms associated with depression. The researchers gave a forced swimming test to 100 rats, some healthy and some with cancer, and found that the sick rats did not try as hard to escape—a behavior similar to that seen in humans with depression. The sick rats were also less interested in sugar water, which is the the clear preference for healthy rats.
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The oldest known fossil of a human child with a skull deformity has been discovered, suggesting that early humans did not kill or abandon their abnormal offspring, as has been commonly assumed. A research team reconstructed the 530,000-year-old skull, the first pieces of which were unearthed in Spain in 2001, and determined that the child likely suffered from craniosynostosis, a debilitating genetic disorder in which some pieces of the skull fuse too quickly, causing pressure to build in the brain [Wired] and interfering with brain development. The severity of the deformity is not clear, but researchers say the child probably had learning difficulties and other mental health issues, and certainly would have required extra care.
The child belonged to the species Homo heidelbergensis, who lived in Europe 800,000 years ago and may have been the direct ancestors of Neanderthals. Humans are thought to be unique in the way they care for sick individuals. Researchers call it conspecific care, but most laypeople would probably call it compassion. Other primates don’t display similar behavior, so we know humans evolved the ability at some point, even if scientists can’t quite pinpoint when. The work could mean that humans as far back as half a million years ago had differentiated from our primate ancestors [Wired].
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Today four Russians, a German and a Frenchman walked into a mocked-up spacecraft and swung the metal hatch shut behind them. If all goes as planned, that hatch won’t open again for 105 days. The six men have volunteered to spend more than three months in isolation to simulate the experience of a manned flight to Mars. The crew will subsist on freeze-dried space rations and will clean themselves with wet wipes; they’ll also go without smoking, alcohol, TV, and internet. Their only link to the outside world will be communications sessions with the mission control and an internal e-mail system. Communications with the mission controllers will have 20-minute delays to imitate a real flight [AP].
This project is a warm up for a much more ambitious experiment, scheduled for December, which will see another group of volunteers spending over 500 days in the same conditions. With current technology it is estimated that a return trip to Mars would take at least 18 months [Telegraph].
The current experiment won’t simulate some of the most daunting obstacles to interplanetary travel, like increased radiation exposure and the physical effects of prolonged weightlessness. Instead, it will focus on the psychological impact of isolation from the outside world and close proximity to just a few people. “Working in such conditions requires that a person be able to check himself, evaluate his condition in relation to the crew and in relation to mission control and be able to correct himself,” said Boris V. Marukov, the experiment’s director and a former crew member on the International Space Station. “He will be a psychotherapist for himself” [The New York Times].
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People with a family history of depression have an altered brain anatomy, a new study says, even if they themselves have never experienced clinical depression. Brain scans showed a 28-percent thinning in the right cortex — the outer layer of the brain — in people who had a family history of depression compared with people who did not. “The difference was so great that at first we almost didn’t believe it. But we checked and re-checked all of our data, and we looked for all possible alternative explanations, and still the difference was there” [Reuters], said study coauthor Bradley Peterson.
Researchers scanned the brains of 131 individuals ranging in age from 6 to 54, about half of whom came from families with a history of depression. The team was looking specifically for abnormalities in the brain that could signal a predisposition to depression, rather than changes that may be caused by the disease [Reuters]. The cortical thinning seems to fit the definition as a warning flag. Says Peterson: “That’s what is so extraordinary. You’re seeing it two generations later, and you’re seeing it in both children and adults…. And it’s present even if those offspring themselves have not yet become ill” [The New York Times].
The cerebral cortex is largely responsible for reasoning, planning, and mood, and researchers suggest that its thinning may interfere with a person’s ability to interpret social and emotional cues from others. Interestingly, not all of the subjects with depressed family members showed thinning on both sides of their cortices; it was primarily those with thinning in the left hemisphere who had actually developed depression.
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To figure out whether you’ll like the restaurant around the corner or that new guy in accounting or a vacation in Madrid, or just about anything else you’ve never personally experienced, try asking a stranger who has [Time]. That stranger is likely to predict, better than you can yourself, how much enjoyment you’ll get from that new experience (or the guy in accounting).
Previous research has shown that people tend to overestimate how disappointed or unhappy they will be after a perceived negative event, such as being denied a promotion, as well as how happy they will feel after positive events, like winning a prize. Building on that knowledge, psychology professor Daniel Gilbert conducted experiments in which he asked people to predict how much they’d enjoy a future event that they knew nothing about—except how much a total stranger had enjoyed it. Those people, it turns out, made extremely accurate predictions [WebMD].
In one experiment, women were asked to partake in “speed dating.” Subjects given reviews by women who had already “dated” participating men were able to gauge how well a date would go better than those who were only shown a picture and profile, and asked to come to their own conclusions.
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A controversial autism treatment has gotten a credibility boost. The first rigorously scientific study of hyperbaric oxygen treatment, in which autistic children breathe in extra oxygen inside a pressurized chamber, found that children who received the treatment showed improvement in social interactions, although researchers note that the small study didn’t examine whether the treatment had long-term effects.
Study leader Dan Rossignol says the use of hyperbaric therapy for autism has been gaining popularity in the US where parents can buy their own hyperbaric chamber if they have a spare $14-17,000 [BBC News]. Other parents take their children to clinics for treatments that usually cost between $120 and $150 per session, and which typically aren’t covered by insurance providers. Rossignol says he expects the findings to generate controversy, and notes that he too was initially very sceptical of the idea but was prompted to do more research after the treatment showed benefits for his two sons who have autism. “We’re certainly not talking about a cure, we’re talking about improvements in behaviour, improving certain functions and quality of life” [BBC News].
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Using not much more than a brain scanner, scientists have successfully found a way to read people’s minds—or at least, certain thoughts in them. A London research team was able to determine where its volunteer subjects were located, in a computer-generated virtual environment, by using fMRI scanning to analyze activation patterns in the hippocampus area of their brains. After correlating this information with the subjects’ movements, the researchers found that they could accurately predict their subjects’ locations based solely on the scanner read-out.
The findings may bring scientists one step closer to understanding the workings of the hippocampus, the part of the brain responsible for short-term memory and spatial relationships but which has been too disorganized for scientists, until now, to decode. Led by Eleanor Maguire, the researchers focused on groups of neurons identified by Maguire in an earlier study of London taxi drivers, whose hippocampi were hyperdeveloped by years of mental navigation through the city’s mazelike streets…. The results “are an intriguing first step toward using fMRI to read out information about visuo-spatial scenes,” [Wired] said Arne Ekstrom, a California-based neuroscientist.
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Researchers have developed a treatment based on an injection of neural stem cells encased in a biodegradable polymer that replaced the brain tissue in rats that had been damaged by stroke. Led by British neurobiologist Mike Modo, the team was able to show that the hole in the brains of rats caused by a stroke was completely filled with “primitive” new nerve tissue within seven days. This raises the possibility of radically better treatments for a condition that is the leading cause of adult disability in industrialized countries [Technology Review].
Previous stem cell research in rats with stroke damage had seen some success, but was limited by the tendency of the cells, which lack structural support, to migrate into tissue outside the targeted area. For the new study, which will be published in Biomaterials, the researchers used the polymer PLGA to construct tiny balls one-tenth of a millimeter thick, and loaded them with neural stem cells. These were injected into holes in the brain created when the immune system removes dead tissue caused by a stroke. The polymer’s ready-made support structure helped the stem cells to form new brain tissue in the cavity [BBC].
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Deep brain stimulation can now be used to treat obsessive compulsive disorder, or OCD, which causes uncontrollable worries and anxiety in its sufferers. Medtronic’s Reclaim deep-brain stimulation (DBS) device received approval from the Food and Drug Administration after a study of 26 patients with severe OCD that showed a 40 percent reduction in symptoms after a year of deep brain stimulation therapy. All the patients had tried and failed other therapies [Chicago Tribune].
The Reclaim device is implanted under the skin of the chest and then connected to four electrodes in the brain. The electrodes deliver steady pulses of electricity that block abnormal brain signals [AP]; the device is controlled by a battery-run component outside the body. Hooman Azmi, a neurosurgeon at Hackensack University Medical Center, said, “This is essentially like a pacemaker for the brain” [WebMD Health News].
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Victims of child abuse may bear chemical marks on their genomes that alter the way they respond to stress as adults, according to a small study. Researchers say they detected changes, almost like genetic scars, to a region of the genome that either promotes or tamps down the expression of a certain gene involved in stress responses. This could help explain why childhood abuse, such as sexual abuse or neglect, can cause depression, other mental health effects and suicide, and could some day lead to treatments to help victims overcome their abusive childhoods [Reuters].
Researchers studied 36 brain samples from the Quebec Suicide Brain Bank: 12 from suicide victims who had been abused as children, 12 from suicide victims that suffered no known abuse, and a final 12 who died suddenly in accidents. They found that only the brains of abuse victims showed the changes.
The results are the latest exciting findings in the young field of epigenetics, the process by which environmental factors can alter the expression of genes. In epigenetic changes, the DNA sequence itself isn’t altered, but other mechanisms change certain genes’ activities. Psychiatrist Jonathan Mill says of the new study: “Whilst these results obviously need to be replicated, they provide a mechanism by which experiences early in life can have an effect on behaviour later in adulthood. The exciting thing about epigenetic alterations is that they are potentially reversible, and thus perhaps a future target for therapeutic intervention” [BBC News].
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People may become less vulnerable to bad memories by taking drugs commonly used to treat heart conditions, say Dutch researchers in a paper published in Nature Neuroscience. They believe beta-blocker drugs, usually given to patients following a heart attack or to manage hypertension, could help people suffering from anxiety and other consequences from tramautic experiences.
Led by Merel Kindt, the research team created a fearful memory in 60 subjects by associating a photograph of a spider with an electric shock. A day later, participants who had been given propranolol, a beta-blocker drug, showed less fear when exposed to the image again than did those who were given a placebo. The effect persisted even after the drug was out of the system and the subjects were retested. “The people did not forget seeing the photograph of the spider, but the fear associated with the image was erased” says Kindt [Science News].
This new use for beta-blockers depends on the mental mechanics involved with storing and remembering: Each time a memory is recalled it changes a little, and the new version is recorded in the long-term memory stash via brain chemical fluctuations in a process called reconsolidation. The beta-blockers could interfere with [certain other] brain chemicals, blocking reconsolidation of the emotional component of the memory, but leaving the rest of the memory intact [Science News]. Scientists are excited by the implications that the discovery could have for treating patients dealing with anxiety.
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Playing the absorbing video game Tetris immediately after a traumatic experience could reduce the most jarring symptom of post-traumatic stress disorder (PTSD), the flashbacks in which the distressing memory invades the brain. In an odd new study, researchers showed volunteers ugly images of nasty accidents, crushed-up skulls and bloody entrails from various sources. Then they asked half of them to play Tetris. While the other half apparently did nothing…. The Tetris players apparently suffered significantly fewer nasty memories of those ugly images than did those who were left idle [CNET].
The Tetris players may have experienced fewer flashbacks because they were distracted during a crucial window of opportunity, the few hours after the traumatic incident when the brain is consolidating the memory. Says lead author Emily Holmes: “We wanted to find a way to dampen down flashbacks - the raw sensory images of trauma that are over-represented in the memories of those with PTSD. Tetris may work by competing for the brain’s resources for sensory information. We suggest it specifically interferes with the way sensory memories are laid down in the period after trauma and thus reduces the number of flashbacks that are experienced afterwards” [BBC News]. Playing Tetris could be considered a “cognitive vaccine” against flashbacks, Holmes suggested.
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Gay young adults who were rejected by their families when they came out as teenagers are much more likely to attempt suicide, have unprotected sex, and have problems with drug use and depression, according to a new study. The findings are based on surveys of 224 gay, lesbian, bisexual and transgender adults in California who ranged in age from 21 to 25. Gay Latinos were most likely to experience a poor reception from their parents, and had the highest rates of risk factors for HIV and mental health problems, according to the research [Scientific American].
The findings, published in the journal Pediatrics [subscription required], don’t prove that a family’s negative reaction to a child’s sexuality directly causes problems later in life. But it’s clear that “there’s a connection between how families treat gay and lesbian children and their mental and physical health” [HealthDay News] said social worker Caitlin Ryan, the study’s lead author. She found that teenagers who were rejected by their families were eight times as likely to attempt suicide, six times as likely to report serious depression, and three times as likely to have unprotected sex and use drugs.
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Happiness is catching and spreads like the flu, according to a study that followed a whole community of people for 20 years. The effect of one happy person could ripple through three degrees of separation, researchers report. “It is sometimes said that you can’t be happier than your least happy child. It is truly amazing to discover that when you replace the word ‘child’ with ‘best friend’s neighbor’s uncle,’ the sentence is still true,” [Boston Globe] said psychologist Daniel Gilbert, who was not involved in the study. The researchers liken the pattern of happiness transmission to the spread of a virus: those with the most number of happy contacts are the mostly likely to catch the happy bug.
The study, published in the British Medical Journal, followed more than 4,700 people living in Framingham, Massachusetts from 1983 to 2003. The participants answered periodic questionnaires about their emotional well-being and listed the names of relatives, friends, and co-workers, many of whom were also participating in the study. Researchers found that happiness wasn’t scattered evenly throughout the population but instead seemed to spread through social networks. “Happiness is like a stampede,” said [co-author] Nicholas Christakis… “Whether you’re happy depends not just on your own actions and behaviors and thoughts, but on those of people you don’t even know” [AP].
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