TIME Social Media

Calm Down: Facebook Isn’t Manipulating Your Emotions

Yes, they played with your News Feeds. Yes, that’s creepy. But here’s why you shouldn’t be so shocked and upset

Have you heard that you might have been Facebook’s guinea pig? That the company, working with some scientists, fiddled around with 698,003 people’s News Feeds in January 2012 and tried to make the users feel sadder (or happier) by manipulating what members read?

Shocked? Violated? Creeped out? Well, be prepared to be even more shocked, violated and creeped out. Because what Facebook did was scientifically acceptable, ethically allowable and, let’s face it, probably among the more innocuous ways that you’re being manipulated in nearly every aspect of your life.

First things first. The researchers didn’t “make” users feel sadder or happier. What they did was make it more or less likely for them to see posts that contained either slightly more negative language or slightly more positive language. Overall, those who had emotionally charged messages hidden from their News Feed used fewer words when posting, and those who did see emotional words tended to reflect the tone of their feeds when they posted. But there’s a difference between using, as the study found, one more negative word per 1,000 in a week of posts, and what psychologists would call feeling sad or depressed.

Adam Kramer of Facebook, one of the study’s co-authors, posted on an apology of sorts, for the way the study was presented. “My co-authors and I are very sorry for the way the paper described the research and any anxiety it caused,” he wrote.

But the study is not without value, says Dr. Nicholas Christakis, director of the Human Nature Lab at Yale University who has studied emotional contagion across social networks. “The scientific concerns that have been raised are mostly without merit,” he says. He points out that while the positivity or negativity of words may not be a validated measure of mood, the fact that the study found similar effects in both directions – people were affected in similar ways when the number of negative and positive words were manipulated in their feeds – suggests emotional contagion on social media is, indeed, real.

Concerns about people’s privacy being violated by the experiment may also be unwarranted. First, Facebook users know that their data is no longer exclusively their own once it’s on the site. And the whole premise of News Feed is that it’s a curated glance at the most appealing or engaging updates your network of friends might post. That’s why the Cornell University Institutional Review Board (IRB), which reviews and approves all human research studies conducted by its members, gave the experiment the green light. They determined that the study posed minimal risk of disrupting people’s normal environments or behavior, and therefore waived the need for getting informed consent from each participant (something that IRBs routinely do for studies involving medical records, prison records and educational information as long as the scientists maintain the anonymity of the owners of the data).

Should the 698,003 users have been told once the study was done? Perhaps, but only out of courtesy, and not for any legal or ethical reasons. “Certain items weren’t shown to people in their News Feed,” says James Fowler, professor of medical genetics and political science at University of California San Diego, who has collaborated with Christakis and has spoken with Facebook about the company’s research. “This sounds like something that happens to people ordinarily. As a consequence, I’m having a hard time understanding why people are so upset.”

“Things that happen to you that you aren’t aware of can be scary to people,” says Fowler. That could explain why, despite the fact that Fowler and Christakis conducted a similar intervention by seeding Facebook users’ accounts with messages from friends asking them to vote at an election, they weren’t accused of manipulating people in the same way. “It’s fascinating to me that everyone is piling on [this study] when we have already done it,” Fowler says of tweaking people’s social network to see how it influences their reactions.

It’s not that anyone condones the fact that we’re being studied and analyzed all the time (the fact that you clicked on this story was recorded by this site’s administrators, as well as how long you’re taking to read it to see if posts like these are appealing).

But if social networks are here to stay, and if, as many intriguing studies suggest, they do have some influence on the way we act and think, then it’s worth trying to figure out how they do it.

“I wouldn’t want the public outcry to shut down the science,” says Fowler. “I would much rather study it and understand it than stick my head in the sand and avoid the issue altogether.”

TIME Research

In 2025, Everyone Will Get DNA Mapped At Birth

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What will the future hold? REB Images—Getty Images/Blend Images

Scientists have scoured trends in research grants, patents and more to come up with these 10 innovations that will be reality in 10 years (or so they think)

Everybody likes to blue-sky it when it comes to technology. Driverless cars! Fat-burning pills! Telepathic butlers! But the folks at Thomson Reuters Intellectual Property & Science do it for a living—and they do it with data.

By examining who’s investing in what, who’s researching what and who’s patenting what, the group has come up with 10 predictions of innovation for 2025, which they presented at the Aspen Ideas Festival. The list included the first attempts at testing teleportation, the ubiquity of biodegradable packaging and electric air transportation.

Here’s what they say will be commonplace in medicine in a decade:

1. Dementia will be on the decline

While the World Health Organization predicts that more than 70 million people will be affected by dementia, much of it related to Alzheimer’s disease, by 2025, that upward trajectory of cases may be blunted somewhat by advances in genetics that will lead to earlier detection and possible treatment of the degenerative brain disorder.

2. We’ll be able to prevent type 1 diabetes

Unlike type 2 diabetes, which generally develops when the body gradually loses its ability to break down sugar properly, type 1 diabetics can’t produce enough insulin, the hormone that dispatches sugar from the diet. Advances in genetic engineering will lead to a more reliable technique for “fixing” genetic aberrations that contribute to type 1 diabetes as well as other metabolic disorders, making it possible to cure these conditions.

3. We will have less toxic cancer treatments

Building on the promise of targeted cancer therapies, which more precisely hone in on tumor cells while leaving healthy cells alone, researchers will have a deeper knowledge of the Achilles’ heels of cancer cells, which will help them to develop more powerful and precise drugs that can dispatch tumors with fewer side effects.

4. Every baby will get its DNA mapped at birth

It’s already a trendy thing to have your genome sequenced, but today there isn’t much you can do with the information. Having that information, however, may prove useful in the near future, both for predicting your risk of developing diseases as well as your ability to respond (or not) to certain drugs. As knowledge about the genome, and what various genes, or versions of genes do, grows, so will doctors’ ability to predict health outcomes and treat patients based on genetic information. So within a decade, getting a baseline DNA map at birth could be a valuable way of preparing to lead a healthier and possibly longer life.

TIME

Here’s What It Will Take to Contain the Worst Ebola Outbreak in History

Doctors Without Borders is calling the latest outbreak in west Africa “out of control,” and here’s why

+ READ ARTICLE

The “perfect storm” analogy is often over-used when it comes to disease outbreaks–all the elements that you don’t want to see converge to make conditions ripe for a bacteria, or, in this case, a virus, to rip through a population at lightning speed: geography, society, culture, a potent virus, reluctant politicians and a weak health care system. But all those factors are contributing to history’s largest-ever Ebola outbreak, which the World Health Organization now calls a “crisis.” Since early spring, Ebola has spread to two additional countries, Sierra Leone and Liberia, infecting 635 people and claiming nearly 400 lives.

MORE: Ebola Outbreak Beyond Our Control, Doctors Without Borders Says

The Ebola virus causes a nasty infection that triggers an inflammatory reaction so intense, patients essentially drown in their own fluids as they bleed internally and externally — victims’ bodies are overtaken with a well-intentioned defensive system run amok. Anyone who comes into contact with the infected fluids can also get infected. As of now, there are no treatments for Ebola. The only hope is for the body to remain strong enough to overcome the initial onslaught from the virus and start to develop antibodies to fight it. As patients get sick, they stop eating and drinking, becoming too weak to develop these critical antibodies. Left alone, nine out of 10 infected people die. At treatment centers, where doctors can provide supportive care with nutrients and hydration, that figure improves to seven out of 10.

Those aren’t great odds, and social and cultural practices in west Africa may be stacking the deck even further. Dr. Michel Van Herp, a physician and epidemiologist with Doctors Without Borders who traveled to Guinea when the outbreak began, says he has been confronted by hostile villagers who did not welcome the medical help.

“I have had aggressive people in front of me in the village,” Van Herp says, as he tried to bring infected patients to treatment centers. “Most villagers are denying the existence of Ebola.”

MORE: 6 Things to Know About the Latest Ebola Outbreak

That denial is fueled by a strong stigma against the disease. In other parts of central Africa where smaller outbreaks occurred, survivors of Ebola returned to their villages only to find their homes burned and their remaining family members ostracized for having been infected.

Such denial not only increases the risk that the close contacts of those infected by Ebola will be affected, but it also creates the ideal situation for the virus to gain an even broader foothold. A critical first step in containing any outbreak of infectious disease involves carefully tracing which people patients have been in contact with. Only then can scientists start to create barriers against the virus by keeping it contained to people known to have already been exposed. In Guinea, denial and stigma against Ebola means some patients who believe they are infected are fleeing to other villages or even crossing the border to another country.

“If you have a guy who runs away to a village 20 kilometers away, then you need to start from scratch in that village to trace his contacts,” says Van Herp.

MORE: What You Need to Know About the Ebola Virus

Making things worse is the fact that in the part of western Africa where the outbreak is centered, the population is particularly mobile, often traveling to nearby Sierra Leone and Liberia in search of work.

“We’ve seen kids who travel between three or four villages, and between the countries before they are too sick and weak that they aren’t able to work any more,” says Van Herp. “In the meantime they have contaminated three or four villages.”

Cultural practices mean that the potential for transmitting Ebola is also amplified if a respected elder is affected.

“If a guy like this falls sick, then more people try to cure him,” says Van Herp. “If he dies, more people are involved in the process of the funeral–in cleaning the dead body, and preparing the body. We have seen that one patient can give disease to 15 or 20 other people.”

Van Herp plans to return to Guinea in July, but he says that so far, there hasn’t been much improvement in people’s education and acceptance about Ebola, despite the rising number of deaths. The WHO has called an emergency meeting of 11 nations next week to discuss ways of containing the outbreak. Attending will be the Minister of Health from Uganda, where the government has made efforts to address the stigma associated with Ebola by creating a survivors network to educate and inform the public about the disease–and hopefully reduce fear and misperceptions about the virus.

TIME

The Oldest Human Poop Tells Us Neanderthals Ate Plants

Our human ancestors ate a varied diet after all – at least according to their fecal remains

If you think that eating a meat-heavy diet will make you lean like our Neanderthal forebears, you might be disappointed. Researchers analyzing sediment from a mid-Paleolithic era site in Alicante, Spain, report in the journal PLOS One that they have the strongest evidence yet that while Neanderthals did consume a lot of meat, they also ate plants as well.

Previous data on the Neanderthal diet relied on indirect evidence of their meals—residues from cooking equipment, and remnants of their prey in areas that the species was known to inhabit that have survived over the ages. More recently, scientists have even found evidence of plant seeds and animal remains in teeth belonging to Neanderthal specimens, but that doesn’t necessarily mean that those food sources were eaten. Neanderthals used their teeth as tools as well.

MORE: 17 430,000-Year-Old Skulls Discovered in ‘Pit of Bones’

But in analyzing sediment from the Spanish site, Ainara Sistiaga and her colleagues found evidence of human fecal remains, and those provide the best evidence yet of what Neanderthals actually ate and relied on for energy daily.

How did Sistiaga know that the fecal sediment belonged to early humans, and not animals? Thanks to the microbes that live in the human gut, the ratio of certain molecules known as sterols and stanols produced by these bacteria when they digest animal fats and plant fibers is uniquely human. Using that as a fingerprint, Sistiaga confirmed that the sediment belonged to the Neanderthal populations that resided in that region, making it the oldest recorded sample of human fecal remains. “At the beginning we didn’t know what the [ratios] meant, but after some research we are confident that we can apply the technique for the first time in this old sediment,” she says.

Based on that analysis, she and her colleagues could also tell that the Neanderthal diet contained not just large amounts of animal protein but some plant metabolites as well.

Sistiaga, a PhD student at Massachusetts Institute of Technology and University of La Laguna in Spain, plans to study even older fecal matter from other primates as well, including the chimpanzee and gorilla, to better understand when in primate evolution species began to favor meat over plants, and how that change affected their development. In the meantime, it looks like even our Neanderthal forebears knew the benefits of eating a balanced diet.

TIME Research

Here’s What You Use to Fight Antibiotic Resistant Bacteria

Researchers say a tough form of fungus may hold the key to battling the bacteria that are resistant to the strongest antibiotics

There’s a war going on, and most of us can’t even see it. Man has been battling microbes for millennia, and despite their microscopic size, the bugs have been winning. But man may finally have a leg up, scientists from Canada and the U.K. say—and it’s all thanks to a humble fungus.

While antibiotics have been a powerful weapon against bacteria that can cause serious and even fatal infections, the microbes have been just as busy as drug makers in finding ways to evade the medications. What’s more, the man-made compounds also appear to pose little challenge to bacteria, which are surrounded by such molecules, made by their neighbors, other microbes or other organisms in their environments. “Bacteria seem to laugh in their face,” says Gerard Wright, director of the Michael G. DeGroote Institute for Infectious Disease Research at McMaster University and the new study’s senior author. The result? Most antibiotics, including penicillin and the carbapenems that have been introduced more recently, contain a chemical ring that bacteria have been remarkably adept at breaking. Once compromised, the ring and the antibiotic are neutralized.

MORE: Antibiotic-Resistant Bacteria Are Now In Every Part of the World

So most drug companies have tried to develop stronger, or slightly different chemical rings, but Wright and his colleagues decided to tackle the problem from a different tack. Why not disrupt the enzyme that the bacteria were using to disable the antibiotics instead?

It’s an old approach that most pharmaceutical companies have abandoned, since the strategy requires combining an antibiotic with something that disables the bacteria’s ability to resist the drug±two drugs means twice the potential complications and side effects, so most large-scale efforts have focused on building better solo antibiotics.

MORE: Antibiotic Resistant Genes Are Everywhere, Even in Arctic Ice

But aware that nature is a rich resource of organisms that naturally make compounds that can interfere with bacterial enzymes, Andrew King in Wright’s lab screened 500 such molecules and found one, from Aspergillus versicolor, that worked remarkably well in inhibiting New Delhi Metallobeta-Lactamase-1 (NDM-1), an antibiotic resistant gene that the World Health Organization recently called a global public health threat. (He also tested 30,000 synthetic compounds and none inhibited NDM-1.)

“Natural products, and especially natural products that come from microbes like bacteria and fungi, are privileged molecules, in the sense that they are products of evolution themselves, so they are much better at interacting with bacteria,” says Wright, who published his results in the journal Nature. Rather than being relatively simple and flat, like the compounds created in labs, these agents are three-dimensional with structures and functions that are difficult to recreate in a petri dish. “If we want to look for inhibitors of antibiotic resistance on a significant scale, we need to go back to these sources,” he says.

MORE: Why You Need to Worry About NDM-1: Not a ‘Superbug,’ But Still a Threat

The fungus turns out to be one of the most resilient organisms on the planet, able to survive in the harsh climates of the arctic, the salty Dead Sea and even the International Space Station. That hardiness also makes it among the most common molds in damp or water-damaged buildings and moist air ducts.

When Wright and his team tested the fungus in mice infected with lethal doses of K. pneumoniae that carried the NDM-1 resistance to antibiotics, the mice shrugged off the infection. In fact, the fungus allowed the antibiotic to work effectively again, essentially circumventing the bacteria’s attempt at resisting the drug.

“The idea of rescuing our old antibiotics, is something that folks are starting to realize is not only a good idea, but doable,” he says. He and his team hope to find similar inhibitors to neutralize resistance against the other major classes of antibiotics, but as optimistic as Wright is about the strategy, he admits that ultimately the bacteria may find ways to resist even these agents. “Resistance is a natural phenomenon’ it’s just natural selection. There’s no way to get around it.” Except perhaps to stay one step ahead of the microbes and find compounds that can thwart them…again and again.

TIME Breast Cancer

High-Tech 3D Mammograms Probably Saved This Woman’s Life

A large study shows the latest screening tool can detect more cancers with fewer false positives

Lori Safer is a convert. The 55 year old occupational therapist had been told by many mammogram technicians that her breasts were hard to image. Her fibrocystic tissue meant that every mammography report was somewhat less than reassuring. “They would say, ‘It doesn’t’ look like anything is there, but just come back in a year, and we’ll keep an eye on it,’” the New Jersey resident says.

Worried that the mammograms were not picking up on possible cancers, Safer went to University of Pennsylvania, where the breast imaging center was testing a 3D mammogram, which is the subject of a new study published in JAMA. Building on the 2D technology, the 3D version simply slices the images of the breast and reconstructs them on a computer in 3D form, allowing doctors to get a better view of the entire breast and any potential tumors growing within.

Sure enough, the 3D test picked up a suspicious lump. She got a biopsy, and even that was negative, but because the 3D mammogram had detected a potential tumor, doctors recommended she have a lumpectomy to remove the growth. It turned out to be malignant. But because the cancer was picked up in its earliest stages, before any cancer cells could spread to the lymph nodes, Safer is now cancer-free. “If I had waited a year, like I would have if I had been getting the regular mammogram, it could be a totally different story,” she says.

MORE: What Now? 4 Takeaways From the Newest Mammogram Study

The latest research on the 3D mammograms, or tomosynthesis, backs her up. Led by Dr. Sarah Friedewald, chief of breast imaging at Advocate Lutheran General Hospital in Illinois, researchers report that 3D mammograms can pick up more breast cancers and lead to fewer callbacks for repeat testing than 2D mammography. It’s the data that many breast cancer physicians have been waiting for.

Since the Food and Drug Administration approved the first 3D mammogram machine in 2011, doctors have been documenting whether the technology can outperform existing mammography by improving detection of breast cancer while cutting back on false positives. In the JAMA study, the researchers collected data from more than 454,000 mammograms done at 13 sites; nearly a quarter included both the traditional 2D mammogram as well as an additional 3D image. Compared to the 2D mammograms alone, the tomosynthesis improved detection of invasive cancers by 41%, while not increasing rates of picking up DCIS cancers, which don’t spread from the milk ducts and have higher survival rates. That’s important because other technologies, including ultrasound and MRI, led to higher rates of detecting all types of growths, but it’s more important to identify early-stage invasive cancers because treating them can lead to higher remission rates and longer survival.

MORE: The Mammogram Melee: How Much Screening Is Best?

“In my long career, this is the biggest improvement in screening I have seen,” says Dr. Emily Conant, professor or radiology and chief of breast imaging at the University of Pennsylvania Perelman School of Medicine and one of the study’s co-authors. “This is much bigger than the improvement in going from analogue or film to digital; I don’t think there’s a doubt about that.”

The study is the largest to show that 3D mammograms can increase the detection of invasive cancers while lowering the rate of recall testing. “That’s a critical point of 3D,” says Friedewald. “Other screening modalities [such as ultrasound and MRI] have shown that they can pick up additional cancers but none have simultaneously reduced the number of recalls.” Fewer recalls can lead to fewer risks, and costs, for women. Safer, for example, says that she has been called back after a mammogram at least six or seven times for additional testing, which contributed to more time and costs for her, not to mention psychological stress about whether she had cancer.

MORE: Higher Risk for Women With False-Positive Mammogram Results

With these findings, the focus will now shift to figuring out how often women need to be screened using the 3D technology, and how to phase in the machines, which cost $500,000. Not all insurers cover the cost of the 3D screening, which is slightly more expensive than traditional mammography. That could also mean that women requesting it will pay more out-of-pocket as well.

The 3D machines used in the study required women to get double the dose of radiation of a regular mammogram, which was still below the safe levels established. But newer versions of the technology will bring that exposure down to levels similar to those of current mammography machines.

Should every hospital switch to imaging? “I think it’s premature to replace 2D mammography, since we are still trying to understand the utility and limitations of the technology,” says Dr. Therese Bevers, medical director of the cancer prevention center at the University of Texas MD Anderson Cancer Center. “But a test that weighs more favorably toward benefits—and fewer callbacks—is a win-win.”

MORE: Breast Cancer Screening Isn’t Going Away—At Least Not Yet

The researchers hope that that results will convince more insurers to cover 3D imaging on the premise that despite its higher upfront cost, the test’s sensitivity in detecting invasive cancers would lead to cost savings by avoiding costly follow ups and additional testing.

For Safer, there’s no question about what type of mammogram she will be getting from now on. “I called all my friends and relatives, and told them you can’t just go for a regular mammogram,” she says. “I told them they have to go online to find places that have 3D.”

If these results hold up, then those facilities won’t be so hard to find in the near future.

TIME

Too Much of a Good Thing: Kids Get Too Many Vitamins and Minerals

Foods fortified with extra vitamins and minerals may be doing more harm than good

Not only are many popular kids’ foods high in calories and sugar—here are 12 cereals of them that are more than 50% sugar by weight—but they may be packing too many vitamins and minerals, says the Environmental Working Group (EWG).

Manufacturers have been using nutrient fortification as a marketing tool to appeal to parents who want healthier foods for their families, but more isn’t necessarily better when it comes to certain nutrients. The advocacy organization studied 1,556 breakfast cereals and 1,025 snack bars and found that many contained substantially higher amounts of three nutrients—vitamin A, niacin and zinc—than is considered safe by the Institute of Medicine (IOM).

While nutrients are important for health, too much of certain nutrients can have harmful effects. Among the products the EWG tested, 114 cereals contained 30% or more of the Food and Drug Administration’s (FDA) recommended daily values for vitamin A, niacin or zinc, and 27 of the snack bars have more than 50% of the recommended values.

MORE: 12 Breakfast Cereals That Are More Than 50% Sugar

The fortification is especially concerning among children, since the values are set for adults, who are physically larger and need more of the nutrients. Children also typically eat more than one serving of cereal or snack bars in a day, and many also take vitamin supplements, further pushing them toward dangerously high levels of vitamin A, niacin and zinc.

Studies have shown that too much vitamin A can contribute to liver damage, brittle nails and hair loss. Overdoing it with zinc can interfere with normal immune functions, while niacin overages can cause rashes and vomiting.

MORE: Study Finds Folic Acid May Decrease Risk For Autism

The authors say that such excess isn’t as much a problem for children who eat more fresh and unprocessed foods. But in the average U.S. diet, earlier studies documented that 45% of children under 8 years old get too much zinc, 13% eat too much vitamin A and 8% get excessive amounts of niacin from their food alone.

To address the “over-nutrient-izing” of the American public, the IOM established upper limits of daily intake for common vitamins and nutrients, calculated for specific age groups and for pregnant women.

The EWG authors are calling for the FDA to adopt similar age specific guidelines for nutrient intake, and to revise its daily values, which were created before many manufacturers began fortifying their products with extra nutrients. And to avoid overdosing their kids on certain vitamins, parents should stay away from products that contain more than 20% to 25% of daily values for vitamin A, niacin and zinc.

TIME social anxiety

This Is the Brain Circuit That Makes You Shy

Using a new light-based technique, scientists trace the nerve network that lights up when mammals meet

What do you do when you want to study something as complicated as what happens deep in the brain when two strangers meet? You develop a completely new way of tracking nerve connections, and then you test it in mice.

That’s what Dr. Karl Deisseroth, a professor of psychiatry and bioengineering at Stanford University, and his colleagues did. “We know social behavior is complicated, but to be able to delve into the brain of freely behaving mammals and to see the signal in real time predicting their social interaction was very exciting,” says Deisseroth, who published his results in the journal Cell.

Brain researchers have long known that certain chemicals known as neurotransmitters soar or drop depending on what we’re doing and how we feel. Based on these observations, drug companies have developed an armada of medications aimed at mimicking these changes to treat everything from depression, hyperactivity and even social anxiety or shyness. But there’s a difference between observing hormone levels rising or falling and identifying a specific circuit — among the millions that occur in the brain — responsible for how we feel and whether we are friendly at a first meeting, say, or a little more reserved. Studying those circuits has been challenging because scientists simply couldn’t get real-time information about which nerves were firing, and where, when certain behaviors, such as a meet and greet, occurred.

(MORE: The Upside of Being an Introvert (and Why Extroverts Are Overrated))

Deisseroth solved that problem. Using optogenetics and fiber photometry, he was able to tag specific nerves in the brain with light-receptor molecules and connect them to ultra-thin fibers that were tied to a switch. Flip the switch on, and the cells were stimulated; turn it off and they quieted down.

Deisseroth and his team hooked up their show to cells that operated on the brain chemical dopamine. When they turned the system on, the cells would release dopamine, and when that happened, the mice showed more interest in investigating newcomers dropped into their cage — they sniffed, they explored and they engaged. When the dopamine activation was turned off, however, the mice made little effort to acknowledge or investigate the intruder.

(MORE: Study: Nearly 1 in 8 Shy Teens May Have Social Phobia)

While manipulating the social interactions of mice is fascinating in itself, Deisseroth sees his findings as being potentially helpful in treating mental illnesses. The fact that he was able to isolate a single circuit that affected something as complex as social behavior suggests that manipulation of deep brain circuits might be a promising way to treat, or modulate behavior in people as well. What if, for example, it became possible to dampen the social aversion that affects some children with autism? If they could interact with people more comfortably, it might be possible to modulate the other symptoms of their developmental disorder. Or what if hyperactivity could be dialed down? Or depression’s darkest moods lightened in the same way?

Deisseroth stresses that we’re far from even speculating how such therapies might be used, but the possibility that deep brain circuits might be tapped to affect behavior is promising. In the meantime, says Deisseroth, “We know these things are complex. The brain is so mysterious, and psychiatry is so mysterious, so our job for a long time will be to deepen understanding of these complex circuits. If that’s the only thing that comes out of this, that would still be great.”

TIME Autism

Pesticide Exposure During Pregnancy Strongly Linked to Autism

Prenatal exposure to commercial pest spraying can boost risk of autism by up to 60%

Autism cannot be attributed to any one risk factor—genes play a role, as does an expectant mom’s diet, some medications and exposure to environmental pollutants. While previous studies have connected autism to prenatal exposure to agricultural chemicals, it wasn’t clear whether other factors could account for the higher rates of autism among their children. A new study gets closer to the answer.

California laws require that commercial pesticide spraying be recorded. So Irva Hertz-Picciotto, professor of epidemiology at the Mind Institute at University of California, Davis, took advantage of the data showing where pesticides had been sprayed and matched it against pregnant women’s home addresses. About one-third of the mothers-to-be lived under a mile from at least one pesticide application during their pregnancy. If the pesticide was an organophosphate, a class of compounds that has largely been phased out of home bug and lawn sprays but remain in commercial applications, the women showed a 60% higher risk of having a child with an autism spectrum disorder (ASD). Living near a spraying of pyrethroids, which are commonly found in home insect sprays, just before conception or during the third trimester of pregnancy increased by up to two-fold the risk of both ASDs and developmental delays.

Insecticides are known to be toxic to nerves, and developing babies may be especially vulnerable, says Hertz-Picciotto, since their brains are just forming important brain structures and connections that can be disrupted by the chemicals. “Many pesticides operate through affecting the nervous system of lower organisms,” she says. “So they should be taken seriously, because they are by design neurotoxic. The question is at what dose.”

Still, while the study involved more than 1,000 participants, Hertz-Picciotto says it’s not definitive proof that pesticides cause autism. They adjusted for potential factors that could also contribute to higher risk of autism, such as parental age, mother’s health, and distance of the residences from freeways. But they did not have information on how many hours the pregnant women typically spent at home, or on whether they were actually at home during the sprayings. The scientists also did not have information on the mothers’ diets, which could introduce pesticide residue from foods, or their occupations, including whether their workplace exposures might have also played a role in their children’s autism risk.

The association does add to growing data that connects pesticide exposure to potential developmental problems in fetuses, however. The fact that the rates of autism were highest among women who lived closest to the pesticide applications, and lower among those who lived further away, suggests that the chemicals are worth studying further for what role, if any, they play in contributing to autism.

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