The Brains of Anxious People May Perceive the World Differently

iStock
iStock

A study showed that people with generalized anxiety disorder unconsciously label harmless things as threats, which may serve to further their anxiety. These findings were published in the journal Current Biology.

Psychologists recognize several forms of clinical anxiety. The most common is generalized anxiety disorder, or GAD, in which people frequently feel very worried or anxious even when it seems like there’s nothing to worry about. Some studies have suggested that anxiety disorders may stem from a process called overgeneralization.

In overgeneralization, the brain lumps both safe and unsafe things together and labels them all unsafe. For this reason, the researchers also call this the “better safe than sorry” approach. Our brains naturally pay more attention to negative or threatening information in our environments. If anxious people perceive more threats in the world around them, it would make a lot of sense for them to be worried.

To find out if overgeneralization was involved, researchers recruited 28 people diagnosed with GAD and 16 people without anxiety and brought them into the lab. The experiment had two parts: training and testing. In the training section, study participants learned to differentiate between three different sounds. Each sound was tied to a different outcome; pressing a key could lead to winning money (the “positive” tone), losing money (the “negative” tone), or nothing (the “neutral” tone).

In the second phase of the experiment, researchers played 15 different sounds for the participants and asked them to press a key when they heard a sound they recognized from the training phase. If they guessed right, they’d win money, but if they guessed wrong, the researchers would take some of their money back.

Because of the risk of losing money, the best strategy for everyone would be a conservative one—not pressing the button much at all based on the assumption that most of the tones were new. But anxious participants were trigger-happy, believing they’d heard many of the unfamiliar tones before. The experience of winning and losing money in training had made a strong emotional impression on them, which led them to overgeneralize new information as relevant.

The researchers also administered brain scans during the testing phase. They found notable differences between anxious and non-anxious brains. While they were focused on parsing new information, anxious people showed more activation in several parts of the brain, including the amygdala, a region associated with fear and worry.

"We show that in patients with anxiety, emotional experience induces plasticity in brain circuits that lasts after the experience is over," senior co-author Rony Paz said in a press release. "Such plastic changes occur in primary circuits that later mediate the response to new stimuli, resulting in an inability to discriminate between the originally experienced stimulus and a new similar stimulus. Therefore, anxiety patients respond emotionally to such new stimuli as well, resulting in anxiety even in apparently irrelevant new situations. Importantly, they cannot control this, as it is a perceptual inability to discriminate."

Paz noted that in dangerous circumstances, the hyper-vigilance associated with anxiety might be a good thing. The problem is that most circumstances aren’t dangerous. "Anxiety traits can be completely normal, and even beneficial evolutionarily," he says. "Yet an emotional event, even minor sometimes, can induce brain changes that might lead to full-blown anxiety."

Does the Full Moon Really Make People Act Crazy?

iStock.com/voraorn
iStock.com/voraorn

Along with Mercury in retrograde, the full moon is a pretty popular scapegoat for bad luck and bizarre behavior. Encounter someone acting strangely? Blame it on the lunar phases! It's said that crime rates increase and emergency rooms are much busier during the full moon (though a 2004 study debunked this claim). Plus, there's that whole werewolf thing. Why would this be? The reasoning is that the Moon, which affects the ocean's tides, probably exerts a similar effect on us, because the human body is made mostly of water.

This belief that the Moon influences behavior is so widely held—reportedly, even 80 percent of nurses and 64 percent of doctors think it's true, according to a 1987 paper published in the Journal of Emergency Medicine [PDF]—that in 2012 a team of researchers at Université Laval's School of Psychology in Canada decided to find out if mental illness and the phases of the Moon are linked [PDF].

To test the theory, the researchers evaluated 771 patients who visited emergency rooms at two hospitals in Montreal between March 2005 and April 2008. The patients chosen complained of chest pains, which doctors could not determine a medical cause for the pains. Many of the patients suffered from panic attacks, anxiety and mood disorders, or suicidal thoughts.

When the researchers compared the time of the visits to the phases of the Moon, they found that there was no link between the incidence of psychological problems and the four lunar phases, with one exception—in the last lunar quarter, anxiety disorders were 32 percent less frequent. "This may be coincidental or due to factors we did not take into account," Dr. Geneviève Belleville, who directed the team of researchers, said. "But one thing is certain: we observed no full-moon or new-moon effect on psychological problems."

So rest easy (or maybe not): If people seem to act crazy during the full Moon, their behavior is likely pretty similar during the rest of the lunar cycle as well.

This story was updated in 2019.

NASA Reveals How Living in Space for a Year Affected Scott Kelly’s Poop

NASA, Getty Images
NASA, Getty Images

When you agree to be part of a yearlong space study, you forfeit some right to privacy. In astronaut Scott Kelly’s case, the changes his body endured while spending a year at the International Space Station (ISS) were carefully analyzed by NASA, then published in a scientific journal for all to see. Kelly submitted blood samples, saliva samples, and cheek swabs. Even his poop was subjected to scrutiny.

As PBS reports, Scott Kelly’s fecal samples revealed that his gut microbiome underwent significant but reversible changes during his time in orbit. In what was surely good news for both Kelly and NASA, his gut bacteria didn’t contain anything “alarming or scary,” according to geneticist Martha Hotz Vitaterna, and it returned to normal within six months of landing on Earth.

Even after being subjected to the challenging conditions of space, “Scott’s microbiome still looked like Scott’s microbiome, just with a space twist on it,” said Vitaterna, who was one of the study’s authors.

The fecal probe was one small part of a sweeping NASA study that was just published in the journal Science, more than three years after Kelly’s return. Dubbed the Twins Study, it hinged on the results of Kelly’s tests being compared with those of his identical twin, retired astronaut Mark Kelly, who remained on Earth as the control subject.

NASA’s goal was to gain insight into the hazards that astronauts could face on proposed long-term missions to the Moon and Mars. The agency has gone to great lengths to get this information, including offering to pay people $18,500 to stay in bed for two months in order to replicate the conditions of anti-gravity.

It also explains why NASA was willing to launch unmanned rockets into space to collect samples of Kelly’s poop. On four different occasions at the ISS, Kelly used cotton swabs to pick up poo particles. When the rockets arrived to drop off lab supplies, they returned to Earth with little tubes containing the swabs, which had to be frozen until all of the samples were collected. The process was tedious, and on one occasion, one of the SpaceX rockets exploded shortly after it launched in 2015.

The study also found that his telomeres, the caps at the ends of chromosomes, had lengthened in space, likely due to regular exercise and a proper diet, according to NASA. But when Kelly returned to Earth, they began to shorten and return to their pre-spaceflight length. Shorter telomeres have a correlation with aging and age-related diseases. “Although average telomere length, global gene expression, and microbiome changes returned to near preflight levels within six months after return to Earth, increased numbers of short telomeres were observed and expression of some genes was still disrupted,” researchers wrote.

Researchers say more studies will be needed before they send the first human to Mars. Check out NASA's video below to learn more about what they discovered.

[h/t PBS]

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