How a tomato plant foils a dreaded vampire vine

Forget garlic. In real life, a tomato can defeat a vampire. And researchers have now figured out the first step to vegetable triumph.

The vampires are slim, tangling vines that look like splats of orange or yellow-green spaghetti after a toddler’s dinnertime tantrum. Botanically, the 200 or so Cuscuta species are morning glories gone bad. In the same family as the heavenly blue garden trumpets, the dodders, as they’re sometimes called, lose their roots about a week after sprouting and never grow real leaves. Why bother when you can drain food and water from the neighbors?
A dodder seedling, basically a bare stem, finds that first neighbor by writhing and groping (in slow plant time) toward attractive plant odors. “The Cuscuta can smell its victims,” says Markus Albert of the University of Tübingen in Germany.

Depending on the dodder species, victims include asparagus, melons, sugar beets, petunias, garlic, chrysanthemums and oak trees. Even worse for civilization as we know it, some Cuscuta species vampirize coffee plants and grapevines.
Certain dodders do kill tomato plants. But not the C. reflexa from Asia that Albert studies; instead, it gets its skinny little haustoria whipped. Haustoria are the organs that make plant parasitism possible. When a dodder seedling brushes against tasty prey, a haustorium disk forms and pushes out from the dodder stem with a fast-growing point. “It really looks like a vampire tooth,” Albert says.

If the prey is, say, a soybean plant, it’s doomed. The growing dodder haustorium not only exerts force but also releases enzymes that weaken the bean’s tissue. Haustorium tip cells send out projections that grasp the bean’s inner ducts for water and nutrients, diverting so much that the bean starves.

A tomato plant poked by a haustorium, however, panics. A patch of cells on the stem elongate and burst, forming a scab that stops the intruder. The haustorium stalls and eventually dies.

A gene called CuRe1 lets the tomato recognize the dodder as a dire threat, Albert and colleagues report in the July 29 Science. They transferred the gene to a normally susceptible relative and — Ha! Bite that, vampire! Albert predicts additional biochemistry could be needed to dodder-proof other crops. But for starters, researchers now know the first step in protection: A tomato’s rare power to survive a scary vampire is the ability to get really scared itself.

Mosquito moms can pass Zika to offspring

Female mosquitoes carrying the Zika virus can pass the infection to the next generation, lab tests show.

Among Aedes aegypti mosquitoes, thought to be the main species spreading Zika in the Americas, at least one out of every 290 lab offspring catches the virus from its mother, Texas researchers say August 29 in the Journal of Tropical Medicine and Hygiene. Infected eggs, which can survive for months on dry surfaces, could keep the virus circulating even after dry or cold spells, when adult mosquitoes die off, warns Robert Tesh of University of Texas Medical Branch in Galveston.

Earlier research had already shown that youngsters of this species can inherit related viruses, such as those causing dengue, West Nile and yellow fever. Mom-to-egg transmission though is not a given: The same research project also reported no evidence so far of this vertical transmission in 803 offspring of another possible Zika spreader, Ae. albopictus.

It’s not known how likely mosquito moms are to infect their young outside of the lab. Doing a reliable test with wild mosquitoes outdoors is a much more difficult project, the researchers say.

Dwarf lemurs don’t agree on sleep

Contrary to many adorable children’s stories, hibernation is so not sleeping. And most animals can’t do both at the same time.

So what’s with Madagascar’s dwarf lemurs? The fat-tailed dwarf lemur slows its metabolism into true hibernation, and stays there even when brain monitoring shows it’s also sleeping. But two lemur cousins, scientists have just learned, don’t multitask. Like other animals, they have to rev their metabolisms out of hibernation if they want a nap.
Hibernating animals, in the strictest sense, stop regulating body temperature, says Peter Klopfer, cofounder of the Duke Lemur Center in Durham, N.C. “They become totally cold-blooded, like snakes.” By this definition, bears don’t hibernate; they downregulate, dropping their body temperatures only modestly, even when winter den temperatures sink lower. And real hibernation lasts months, disqualifying short-termers such as subtropical hummingbirds. The darting fliers cease temperature regulation and go truly torpid at night. “You can pick them out of the trees,” Klopfer says.

The fat-tailed dwarf lemur, Cheirogaleus medius, was the first primate hibernator discovered, snuggling deep into the softly rotting wood of dead trees. “You’d think they’d suffocate,” he says. But their oxygen demands plunge to somewhere around 1 percent of usual. As trees warm during the day and cool at night, so do these lemurs. When both a tree and its inner lemur heat up, the lemur’s brain activity reflects mammalian REM sleep.

Klopfer expected much the same from two other dwarf lemurs from an upland forest with cold, wet winters. There, C. crossleyi and C. sibreei spend three to seven months curled up underground, below a thick cushion of fallen leaves. “If you didn’t know better, you might think they were dead because they’re cold to the touch,” Klopfer says.

Unlike the tree-hibernators, the upland lemurs take periodic breaks from hibernating to sleep, Klopfer, the Lemur Center’s Marina Blanco and colleagues report in the August Royal Society Open Science. The lemurs generated some body heat of their own about once a week, which is when their brains showed signs of sleep (REM-like and slow-wave). “My suspicion is that sleep during torpor is only possible at relatively high temperatures, above 20º Celsius,” Klopfer says. Sleep may be important enough for cold-winter lemurs to come out of the storybook “long winter’s nap.”

Brain training can alter opinions of faces

By sneakily influencing brain activity, scientists changed people’s opinions of faces. This covert neural sculpting relied on a sophisticated brain training technique in which people learn to direct their thoughts in specific ways.

The results, published September 8 in PLOS Biology, support the idea that neurofeedback methods could help reveal how the brain’s behavior gives rise to perceptions and emotions. What’s more, the technique may ultimately prove useful for easing traumatic memories and treating disorders such as depression. The research is still at an early stage, says neurofeedback researcher Michelle Hampson of Yale University, but, she notes, “I think it has great promise.”
Takeo Watanabe of Brown University and colleagues used functional MRI to measure people’s brain activity in an area called the cingulate cortex as participants saw pictures of faces. After participants had rated each face, a computer algorithm sorted their brain responses into patterns that corresponded to faces they liked and faces they disliked. With this knowledge in hand, the researchers then attempted to change people’s face preferences by subtly nudging brain activity in the cingulate cortex.

In step 2 of the experiment, returning to the fMRI scanner, participants saw an image of a face that they had previously rated as neutral. Just after that, they were shown a disk. The goal, the participants were told, was simple: make the disk bigger by using their brains. They had no idea that the only way to make the disk grow was to think in a very particular way.

For 12 people, the researchers made the disk grow when the participants’ brain activity looked like the activity that corresponded to faces they had liked in the first round. For 12 other people, the disk grew when their brain activity mirrored activity elicited by previously unliked faces. Another six people saw the faces, but didn’t do any disk training. This training lasted an hour each day for three days.

At the end of the training, people induced to call up brain activity similar to positive responses rated previously neutral faces as slightly more positive. “By doing this again and again, subjects began to like what was neutral before,” Watanabe says. And people who had called up activity associated with negative responses rated previously neutral faces as slightly more negative. People who hadn’t trained on the disk didn’t change their ratings. These opinion shifts lasted at least three months, later experiments showed.

Participants were simply told to make the disk bigger; they had no idea what the disk actually represented. “These results are fascinating in showing how nonconscious brain activity can be utilized to modify brain function and behavior in a targeted way,” says neuroscientist Rafi Malach of the Weizmann Institute of Science in Israel.

By showing that neurofeedback can influence complex mental processes, this study and others raise the possibility that similar methods could change the brain in desirable ways. Perhaps this sort of neural training could get rid of problematic patterns of thinking, such as those that come with abnormal fear and depression, Watanabe says.

To study Galápagos cormorants, a geneticist gets creative

Galápagos cormorants are the only flightless cormorant species. Their wings are too small to lift their heavy bodies. To trace the genetic changes responsible for the birds’ shrunken wings, Alejandro Burga needed DNA from the grounded bird and from a few related species. For the UCLA evolutionary geneticist, getting the right DNA was a yearlong effort.

After Galápagos cormorants (Phalacrocorax harrisi) split off from other cormorants, their wings shrunk to 19 centimeters long and their bodies grew to 3.6 kilograms, not a flying-friendly combination. Burga suspected he would have difficulty getting permission to collect DNA from the endangered birds. So he e-mailed “anybody who had ever published anything on cormorants” in the last 20 years, he says.
He found disease ecologist Patricia Parker of the University of Missouri-St. Louis who had collected blood from Galápagos cormorants in 2000 to monitor the spread of pathogens. Getting to the islands takes special permission, long flights and boat trips, but getting DNA from the meter-tall birds wasn’t hard.

“They’re sluggish, and they just sit there and look at you,” Parker says. She shared DNA that had been sitting in her lab refrigerator for more than a decade. Burga used it to reconstruct the cormorants’ genetic instruction book, or genome.

Next he needed comparison DNA from closely related species, such as the double-crested cormorant — a goose-sized waterbird with a broad wingspan. The bird is protected under a migratory bird treaty between the United States and Canada. Since Burga couldn’t just trap one and collect DNA, he got creative. He tried to extract DNA from preserved specimens at the Natural History Museum of Los Angeles County, but the genetic material was unusable. The San Diego Zoo sent samples of a too-distantly related great cormorant. An international bird rescue facility in Los Angeles notified him when someone found a dead cormorant on the beach. Burga rushed over, but the bird was a Brandt’s cormorant — also too far removed in the family tree to be of use.

One e-mail chain led to Paul Wolf, a U.S. Department of Agriculture wildlife disease biologist monitoring Newcastle disease virus in double-crested cormorants in Minnesota. With a special permit, Wolf removed one double-crested cormorant egg from a nest. The egg was at just the right stage of development — when the wings were beginning to grow — to determine which genes are active during wing development. Two down, two to go.

While on Alaska’s Middleton Island studying seabird parasites, Andrew Ramey of the U.S. Geological Survey collected two eggs from pelagic cormorants for Burga.
Burga also enlisted Claudio Verdugo, a molecular epidemiologist at Universidad Austral de Chile in Valdivia. Bird samples can’t be transported between countries because of fears of disease spread. So Burga sent chemicals and protocols to Verdugo, who took DNA from another species, the neotropic cormorant, and sent it to Burga.

With DNA from four cormorant species in hand, Burga and his newfound friends learned that the Galápagos cormorants’ stubby wings result, in part, from mutations in specific genes that encourage limb growth (SN: 6/11/16, p. 11). Burga is now studying how evolution grounded other birds.

Shayan Oveis Gharan finds the shortest route to success

It’s a problem that sounds simple, but the best minds in mathematics have puzzled over it for generations: A salesman wants to hawk his wares in several cities and return home when he’s done. If he’s only visiting a handful of places, it’s easy for him to schedule his visits to create the shortest round-trip route. But the task rapidly becomes unwieldy as the number of destinations increases, ballooning the number of possible routes.

Theoretical computer scientist Shayan Oveis Gharan, an assistant professor at the University of Washington in Seattle, has made record-breaking advances on this puzzle, known as the traveling salesman problem. The problem is famous in mathematical circles for being deceptively easy to describe but difficult to solve. But Oveis Gharan has persisted. “He is relentless,” says Amin Saberi of Stanford University, Oveis Gharan’s former Ph.D. adviser. “He just doesn’t give up.”
Oveis Gharan’s unwavering focus has enabled him to identify connections between seemingly unrelated areas of mathematics and computer science. He scrutinizes the work of the fields’ most brilliant minds and adapts those techniques to fit his purposes. This strategy — bringing new tools to old problems — is the basis for leaps he has made on two varieties of the traveling salesman problem.

“If you want to build a house, you need to have a sledgehammer and a level, a wrench, tape measure,” he says. “You need to have a lot of tools and use them one after another.” Oveis Gharan, age 30, stocks his toolkit with the latest advances in fields with obscure-sounding names, including spectral graph theory, polyhedral theory and geometry of polynomials. And in a twist that only Oveis Gharan saw coming, a recent solution to a long-standing problem originating in quantum mechanics turned out to be the missing piece to one aspect of the salesman’s puzzle.
For a salesman’s tour of five cities, there are just 12 possible routes; it’s easy enough to pick the one that will save the most gas. But for 20 cities, there are 60 quadrillion possibilities, and for 80 cities, there are more routes than the number of atoms in the observable universe. Relying on brute force — calculating the distances of all the possible routes — is intractable for all but the easiest cases. Yet no one has found a simple method that can quickly find the shortest path for any number and arrangement of cities. The quandary has real-world importance: Companies like Amazon and Uber, for example, want to ferry goods and people to many destinations in the most efficient way possible.

Growing up in his home country of Iran, Oveis Gharan discovered a natural appreciation for challenging puzzles. In middle school, he acquired a book of problems from mathematics Olympiad competitions in the Soviet Union. As a student, “I tend to be one of the slower ones,” Oveis Gharan says, noting that he was usually not the first to grasp a new theorem. But within a few years, he had doggedly plowed through the 200-page book.

The effort also provided Oveis Gharan with his first taste of tool collecting, through collaboration with classmates who joined him in working through the math problems. Oveis Gharan found that solutions come easier when many minds contribute. “Each person thinks and solves problems differently,” he says. “Once someone is exposed to many different ideas and ways of thinking on a problem, that will help a lot to increase the breadth of problem-attacking directions.”

Oveis Gharan attended Sharif University of Technology in Tehran before making his first breakthroughs on the traveling salesman problem as a graduate student at Stanford University. He spent over a year cracking just one thorny facet, before moving on to a postdoctoral fellowship at the University of California, Berkeley.
Rather than attacking the problem head-on, Oveis Gharan works on approximate solutions — routes that are slightly longer than the optimal path but can be calculated in a reasonable amount of time. Since the 1970s, computer scientists have known of a strategy for quickly finding a route that is at most 50 percent longer than the shortest possible path. That record held for decades, until Oveis Gharan tackled it along with Saberi and Mohit Singh, then of McGill University in Montreal.

In a paper published in 2011, the team made what might sound like an infinitesimal improvement, shrinking the 50-percent figure by four hundredths of a trillionth of a trillionth of a trillionth of a trillionth of a percentage point. “People make fun of our paper because of that small improvement,” says Oveis Gharan, “but the thing is that in our area, the actual number is not the major question.”
Instead, the goal is to develop new ideas that can begin to crack the problem open, says Luca Trevisan, a computer scientist at Berkeley. “What’s so important is not the specific algorithm that he has devised, but that there is a whole new set of techniques that can potentially be applied to other problems.” Following the advance, other scientists revisited the traveling salesman problem, and decreased the number significantly; the selected route is now at most 40 percent longer than optimal.

To make his breakthroughs, Oveis Gharan keeps tabs on the scientific literature across a variety of mathematical fields. “Every time new papers or new techniques come out, he’s one of the first people who will pick up the paper and read it,” says Saberi. To discover tools outside his areas of expertise, Oveis Gharan poses pieces of the problem to researchers in other fields.

In 2015, Oveis Gharan and computer scientist Nima Anari, then at Berkeley, made further progress on an approximate solution for a more general, and more challenging, version of the traveling salesman problem. In this version, the distance to go from point A to point B might not be the same as going the opposite direction — a plausible situation in cities with many one-way streets. Researchers had a way to estimate the optimum tour length, but they didn’t understand how good the estimate was. Oveis Gharan and Anari showed it was exponentially better than known previously.

To make this advance, Oveis Gharan teased out connections to a seemingly unrelated problem in mathematics and quantum mechanics, known as the Kadison-Singer problem. “That was really surprising,” says computer scientist Daniel Spielman of Yale University, part of a team that solved the Kadison-Singer problem in 2013. “There was no obvious connection,” he says. “Shayan is incredibly brilliant and incredibly creative.”

Oveis Gharan is now focused on a furtherconquest of this version of the traveling salesman problem. Though his new advance helps approximate the optimal tour length, it can’t identify the corresponding route. Next, Oveis Gharan would like to produce an algorithm that can navigate the correct course.

You can bet he’ll continue to add to his tool collection by sampling from related mathematical and computational fields. “The grand plan is: Try to better understand how these different areas are connected to one another,” Oveis Gharan says. “There are many big open problems lying in this intersection.”

Methane didn’t warm ancient Earth, new simulations suggest

Methane wasn’t the cozy blanket that kept Earth warm hundreds of millions of years ago when the sun was dim, new research suggests.

By simulating the ancient environment, researchers found that abundant sulfate and scant oxygen created conditions that kept down levels of methane — a potent greenhouse gas — around 1.8 billion to 800 million years ago (SN: 11/14/15, p. 18). So something other than methane kept Earth from becoming a snowball during this dim phase in the sun’s life. Researchers report on this new wrinkle in the so-called faint young sun paradox (SN: 5/4/13, p. 30) the week of September 26 in the Proceedings of the National Academy of Sciences.

Limited oxygen increases the production of microbe-made methane in the oceans. With low oxygen early in Earth’s history, many scientists suspected that methane was abundant enough to keep temperatures toasty. Oxygen may have been too sparse, though. Recent work suggests that oxygen concentrations at the time were as low as a thousandth their present-day levels (SN: 11/28/14, p. 14).

Stephanie Olson of the University of California, Riverside and colleagues propose that such low oxygen concentrations thinned the ozone layer that blocks methane-destroying ultraviolet rays. They also estimate that high concentrations of sulfate in seawater at the time helped sustain methane-eating microbes. Together, these processes severely limited methane to levels similar to those seen today — far too low to keep Earth defrosted.

New book tells strange tales of evolution

The Wasp That Brainwashed the Caterpillar Matt Simon Penguin Books, $20
Writer Matt Simon begins his new book with a bleak outlook on life: “In the animal kingdom, life sucks and then you die.” But thanks to evolution — which Simon calls “the most majestic problem-solving force on planet Earth” — some critters have peculiar adaptations that make life suck a little less (though sometimes at the expense of other species).

From mustachioed toads to pink fairy armadillos, Simon’s debut book, The Wasp That Brainwashed the Caterpillar, recounts an eclectic cadre of animals that use creative and often bizarre solutions to find love, a babysitter, a meal or a place to crash.
Take, for instance, the book’s title characters. Technically, it’s the wasp larvae that brainwash the caterpillar. Once a female Glyptapanteles wasp deposits eggs into a living caterpillar, she takes off, leaving the oblivious host to babysit her young. After hatching, some larvae stay behind to release chemicals that manipulate the caterpillar’s brain. Once their siblings erupt from the poor creature’s body, the caterpillar mindlessly protects the youngsters from predators.

Mind control isn’t unique to wasps — flies and even fungi do it, too. But the book is about more than just the seemingly diabolical tactics of parasites. Prey species also have skin, or in some cases snot, in the game.

Hagfish, eel-like fish that scavenge the seafloor, eject thick, slimy mucus to clog the gills of sharks that try to make a meal of the hagfish. And the East African crested rat protects itself from dogs and other predators by slathering its fur with the chewed-up bark of the Acokanthera tree, traditionally used by indigenous hunters to make poison arrows. “A species may gain an edge, but any sort of edge is answered,” Simon writes. And so marches on the arms race of natural selection.

The author never dives deeply into exactly how these creatures evolved. The book is a quick, fun read that’s light on science and heavy on snark (not to mention a lot of anthropomorphizing). Readers familiar with Simon’s column for Wired, “Absurd Creature of the Week,” may already be acquainted with some of these animals. But the book is packed full of even more fascinating facts that will both impress and creep out.

Sometimes failure is the springboard to success

Some discoveries originate in failures. Lab failures, of course, can lead to serendipitous findings. Observations that fail to meet your expectations create space for a new idea to take hold. Imperfections — small failures — may tell volumes about how something was made or what it is made of. Exposing flaws in a theory inches scientists closer to a better one. Failure forces us to ask hard questions and look for new answers.
Our cover story follows the aftermath of a recent acknowledgment of a major fail: We haven’t yet taken a complete census of all minerals on Earth. Akin to the search to name all living species on the planet (but less of a moving target), a campaign is under way to add to the more than 5,000 known minerals, freelancer Sid Perkins writes in “Digging Carbon” (SN: 10/15/16, p. 18). It’s a kind of treasure hunt, as these minerals presumably have not yet been found because they are incredibly rare, perhaps existing at only a single location. Especially interesting to rock hounds are the scores of as yet unseen carbon-based minerals predicted to exist by a recent statistical analysis. Hidden in these unexplored gems might lie untold stories about how Earth’s carbon and water cycles have changed over the eons. Just as adding a new bird species to a life list is exciting for bird watchers, finding a new kind of mineral is what many rock hounds aspire to.
Another kind of failure may explain a mysterious missing star, Christopher Crockett reports in “Lost star may be failed supernova” (SN: 10/15/16, p. 8). A giant star, 25 to 30 times as massive as the sun, flared and then fizzled in 2009. Scientists now say it might be a failed supernova, a dying star that didn’t have quite the right stuff to explode and instead went from star straight to black hole. If the star is not just hiding somewhere in the dust, it’s a new cosmic character, a new type of behavior to watch for.

Imperfections in humans’ DNA help make each of us unique. These imperfections, viewed at a population scale, also offer a way (still imperfect in itself) to track ancestry, to get some idea of how human populations moved, mingled and changed in the deep past. In “The Hybrid Factor” (SN: 10/15/16, p. 22), Bruce Bower describes how recent DNA studies of ancient hominids are changing views of human evolutionary history. Early humans, the data show, mated with Neandertals and possibly other hominids, producing viable hybrid offspring. The research gives support to a longtime contention by some paleoanthropologists that certain ancient skeletons might represent human-Neandertal mixes. Further evidence for this point of view is now coming from studies of hybrid baboons and other modern species. Mixing species, it seems, was sometimes a success.

Examining the DNA of wide swaths of living people is also revising ideas about when early humans migrated out of Africa to settle the rest of the globe. Three new studies, described by Tina Hesman Saey in “One Africa exodus populated globe” (SN: 10/15/16, p. 6), suggest that the major ancestral mass migration from Africa occurred between 50,000 and 75,000 years ago. Those migrants succeeded in leaving their genetic mark on all of today’s non-Africans. Other evidence points to earlier, smaller migrations from Africa. Perhaps those were failures in a sense, failing to seed lasting populations in far-off outposts. But, perhaps those earlier, smaller scale treks were just the first steps toward success.

Erasing stigma needed in mental health care

Scientists, politicians, clinicians, police officers and medical workers agree on one thing: The U.S. mental health system needs a big fix. Too few people get the help they need for mental ailments and emotional turmoil that can destroy livelihoods and lives.

A report in the October JAMA Internal Medicine, for instance, concludes that more than 70 percent of U.S. adults who experience depression don’t receive treatment for it.

Much attention focuses on developing better psychiatric medications and talk therapies. But those tactics may not be enough. New research suggests that the longstanding but understudied problem of stigma leaves many of those suffering mental ailments feeling alone, often unwilling to seek help and frustrated with treatment when they do.
“Stigma about mental illness is widespread,” says sociologist Bernice Pescosolido of Indiana University in Bloomington. And the current emphasis on mental ills as diseases of individuals can unintentionally inflame that sense of shame. An effective mental health care system needs to address stigma’s suffocating social grip, investigators say. “If we want to explain problems such as depression and suicide, we have to see them in a social context, not just as individual issues,” Pescosolido says.

Stigma as a mark of disgrace that taints someone in others’ eyes goes back several millennia. Sociologist Erving Goffman wrote in 1963 of stigma as a “spoiled identity” caused by society’s negative attitudes toward conditions such as mental illness. New evidence supports the idea that stigma about psychological problems runs surprisingly deep. What’s more, it filters through families and communities in different ways.

Many depressed people experience their condition primarily as a family predicament, not a brain disease, says a team led by UCLA psychiatrist and medical anthropologist Elizabeth Bromley. Those who seek treatment from primary care physicians feel tremendous shame about depression-related problems, such as being unable to work, that put a burden on their families. They hide their depression and any treatments, fearing rejection by those closest to them, Bromley and her colleagues report in the October Current Anthropology. Even if antidepressants ease symptoms such as insomnia and fatigue, depressed individuals describe the treatment as a Band-Aid stuck on unresolved family fractures, which can include a violent spouse or drug-addicted child.

Bromley’s team examined data from 46 people, representing various ethnic backgrounds and economic classes, identified in primary care clinics in 1996 as having depression. After their diagnosis, participants completed surveys every six months for two years, then at the five-year and nine-year marks. Interviews about symptoms, treatments and coping occurred at a 10-year follow-up.

Only two people described the depression treatment they received as helpful and appropriate to their situation. Both had family and friends who had noticed their depression symptoms and encouraged them to seek help.
The remaining 44 people spoke of depression as a threat to their closest relationships and family standing. They kept treatment secret to avoid intensifying family conflicts and for fear of rejection. Shame and emotional distance from family members remained even if depression treatments had positive effects. Participants commonly spoke of not wanting to burden their families with their condition. Several said that being singled out for treatment, which only required that one take antidepressants or, say, learn relaxation techniques, made them feel more estranged than ever from already fragile families and, what’s more, did nothing to resolve underlying family troubles.

“Individually focused, biomedical approaches can feel stigmatizing to many people with depression,” Bromley says.

Her team’s findings fit with previous observations that stigma discourages many people from discussing depression with their doctors for fear of breaking frayed family ties, writes psychologist Rob Whitley of Montreal’s McGill University in the same issue of Current Anthropology.

Excessively close ties among a network of families can also stoke stigma, researchers find. It can flourish in a wealthy, well-manicured community where everyone knows everyone else, if not in person than by word of mouth, say sociologists Anna Mueller of the University of Chicago and Seth Abrutyn of the University of Memphis.

In one such town, given the fictional name Poplar Grove by the researchers to protect privacy, teenagers struggle mightily under the weight of an “overactive grapevine of gossip.” Parents and peers constantly monitor whether teens live up to a community-wide standard of high academic achievement, the researchers report in the October American Sociological Review. Hard work is admired, but only if it yields superior grades with no signs of extra effort, such as using tutors. Academic struggles, anxiety and depression are stigmatized as signs of imperfection. As a result, most young people fear to seek any help from adults, including parents and teachers. That situation contributed to a rash of 19 suicides among current students and recent graduates of the town’s high school between 2000 and 2015, Mueller and Abrutyn propose.

The pair conducted interviews and focus groups in 2014 and 2015 with 110 volunteers, including teens who grew up in the town and lost a friend to suicide, parents whose children killed themselves, mental health workers in the town and high school teachers and counselors. In public forums held afterward, residents were surprised to hear from Mueller that one of Poplar Grove’s strengths — strong ties among neighbors concerned about the welfare of everyone’s kids — had a dark side. Parents talked about the shame they felt if a child experienced emotional problems and of feeling like bad parents when word got around. Teens expressed intense fear of failing to ace schoolwork and make it seem effortless. Students who had killed themselves were described by friends as having emotionally wilted under those pressures.

Bromley’s and Mueller’s findings underscore the need for mental health services that reach people where they live, Pescosolido says. Local services stand the best chance of getting troubled individuals to see help-seeking as acceptable behavior with the potential to change one’s life for the better.

Possible approaches include training pastors and other religious leaders in how to assist those with mental disorders and establishing public self-help groups and high school clubs devoted to open discussion and support. Local centers housing teams of social workers and counselors able to coordinate care for serious mental disorders would be a big advance, she says.

Job No. 1, Mueller says, involves getting beyond the popular assumption that mental illness and suicide arise solely in individuals. It’s long been known, for example, that chaotic communities where people feel isolated push suicide rates higher. But as Poplar Grove demonstrates, really tight-knit communities can have the same effect. “Deep psychological pain often has family and community sources,” she says.