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Brain Scans Show 4 Different Types of Depression

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Scientists say they’ve found neurological evidence of four different subtypes of depression—a discovery that may someday help doctors select the best treatment for their depressed patients. The research was published in the journal Nature Medicine.

Depression is an exceptionally slippery beast. Unlike ailments located elsewhere in the body, mental illnesses are classified and diagnosed not by concrete physical signs, or biomarkers, but by patients’ behavior. There are a lot of problems with this approach, including the fact that a lot of different illnesses can cause the same symptoms—and that the same illness can cause different symptoms in different people.

What we call “depression” is an experience that likely has many different causes, co-author Conor Liston of Weill Cornell Medical College told Scientific American. “The fact that we lump people together like this has been a big obstacle in understanding the neurobiology of depression.”

Liston and his colleagues analyzed functional magnetic resonance imaging (fMRI) scans from 17 different research sites around the world. They took in scans from 1188 people, about 40 percent of whom had depression, and were able to look closely at an astounding 258 brain regions in each person.

The team had expected to find some differences between the brains of people with depression and without. They found those, but they also found differences within the group of depressed people. Differences in brain activity and connectivity revealed four distinct subtypes among people with depression.

Most excitingly, these brain-activity subtypes matched up with different medical profiles. Patients in subtypes 1 and 2 described feeling more fatigue, while people in subtypes 3 and 4 had trouble feeling pleasure.

The subtypes also responded differently to treatment techniques. People in subtype 1, for example, were more likely to experience relief with transcranial magnetic stimulation (TMS), a non-pharmaceutical method that uses electromagnetic impulses to stimulate a sluggish brain.

More research is needed, but these findings are both heartening and promising, Liston says. Depression “is not just one biological thing.”

[h/t Scientific American]

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Animals
Owning a Dog May Add Years to Your Life, Study Shows
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We've said that having a furry friend can reduce depression, promote better sleep, and encourage more exercise. Now, research has indicated that caring for a canine might actually extend your lifespan.

Previous studies have shown that dog owners have an innate sense of comfort and increased well-being. A new paper published in Scientific Reports and conducted by Uppsala University in Sweden looked at the health records of 3.4 million of the country's residents. These records typically include personal data like marital status and whether the individual owns a pet. Researchers got additional insight from a national dog registry providing ownership information. According to the study, those with a dog for a housemate were less likely to die from cardiovascular disease or any other cause during the study's 12-year duration.

The study included adults 40 to 80 years old, with a mean age of 57. Researchers found that dogs were a positive predictor in health, particularly among singles. Those who had one were 33 percent less likely to die early than those who did not. Authors didn't conclude the exact reason behind the correlation: It could be active people are more likely to own dogs, that dogs promoted more activity, or that psychological factors like lowered incidences of depression might bolster overall well-being. Either way, having a pooch in your life could mean living a longer one.

[h/t Bloomberg]

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Live Smarter
Not Sure About Your Tap Water? Here's How to Test for Contaminants
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In the wake of Flint, Michigan's water crisis, you may have begun to wonder: Is my tap water safe? How would I know? To put your mind at ease—or just to satisfy your scientific curiosity—you can find out exactly what's in your municipal water pretty easily, as Popular Science reports. Depending on where you live, it might even be free.

A new water quality test called Tap Score, launched on Kickstarter in June 2017, helps you test for the most common household water contaminants for $120 per kit. You just need to take a few samples, mail them to the lab, and you'll get the results back in 10 days, telling you about lead levels, copper and cadmium content, arsenic, and other common hazardous materials that can make their way into water via pipes or wells. If you're mostly worried about lead, you can get a $40 test that only tells you about the lead and copper content of your water.

In New York State, a free lead-testing program will send you a test kit on request that allows you to send off samples of your water to a state-certified lab for processing, no purchase required. A few weeks later, you'll get a letter with the results, telling you what kind of lead levels were found in your water. This option is great if you live in New York, but if your state doesn't offer free testing (or only offers it to specific locations, like schools), there are other budget-friendly ways to test, too.

While mailing samples of your water off to a certified lab is the most accurate way to test your water, you can do it entirely at home with inexpensive strip tests that will only set you back $10 to $15. These tests aren't as sensitive as lab versions, and they don't test for as many contaminants, but they can tell you roughly whether you should be concerned about high levels of toxic metals like lead. The strip tests will only give you positive or negative readings, though, whereas the EPA and other official agencies test for the concentration of contaminants (the parts-per-billion) to determine the safety of a water source. If you're truly concerned with what's in your water, you should probably stick to sending your samples off to a professional, since you'll get a more detailed report of the results from a lab than from a colored strip.

In the future, there will likely be an even quicker way to test for lead and other metals—one that hooks up to your smartphone. Gitanjali Rao, an 11-year-old from Colorado, won the 2017 Young Scientist Challenge by inventing Tethys, a faster lead-testing device than what's currently on the market. With Tethys, instead of waiting for a lab, you can get results instantly. It's not commercially available yet, though, so for now, we'll have to stick with mail-away options.

[h/t Popular Science]

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