Brain Scans Show 4 Different Types of Depression

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iStock

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]

Chronic Pain Happens Differently in Men and Women

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iStock.com/PeopleImages

Women often feel colder than men due to physical differences. Now, a new study shows that the two sexes have different biological processes underlying a specific kind of pain, too. As WIRED reports, research published in the journal Brain revealed that different cells and proteins were activated in men and women with neuropathic pain—a condition that is often chronic, with symptoms including a burning or shooting sensation. While scientists say further research is needed, these findings could potentially change the way we treat conditions involving chronic pain.

A team of Texas-based neurologists and neuroscientists looked for RNA expressions in the sensory neurons of spinal tumors that had been removed from eight women and 18 men. Some of the patients had pain as a result of nerve compression, while others had not experienced any chronic pain. While studying the neurons of women with pain, researchers noticed that protein-like molecules called neuropeptides, which modulate neurons, were highly activated. For the men, immune system cells called macrophages were most active.

"This represents the first direct human evidence that pain seems to be as sex-dependent in its underlying biology in humans as we have been suggesting for a while now, based on experiments in mice," Jeffrey Mogil, a professor of pain studies at Montreal's McGill University, who was not involved in the Brain study, tells WIRED.

So what exactly do these new findings mean for sufferers of chronic pain? Considering that clinical trials and drug manufacturers have traditionally failed to distinguish between the sexes when it comes to developing pain medication, the study could potentially form a foundation for sex-specific pain therapies that could prove more effective. This might be especially promising for women, who are more likely to have some condition that cause persistent pain, such as migraines or fibromyalgia.

"I think that 10 years from now, when I look back at how papers I've published have had an impact, this one will stick out," Dr. Ted Price, a neuroscience professor and one of the paper's authors, said in a statement. "I hope by then that we are designing clinical trials better considering sex as a biological variable, and that we understand how chronic pain is driven differently in men and women."

[h/t WIRED]

McDonald’s Is Testing Out Vegan McNuggets in Norway

McDonald's has never been an especially welcoming place for vegans (until 1990, even the fries contained meat). But now, the chain's Norwegian locations are working to change that. As Today reports, McDonald's restaurants in Norway have launched a vegan nugget alternative to the classic chicken McNugget.

The new vegan McNuggets are prepared to look like the menu item customers are familiar with. They're coated with a layer of breadcrumbs and fried until they're golden-brown and crispy. Instead of chicken meat, the nugget is filled with plant-based ingredients, including mashed potatoes, chickpeas, onions, corn, and carrots.

The vegan McNuggets are only available to customers in Norway for now, but if they're popular, they may spread to McDonald's in other parts of the world. Norway's McDonald's locations also include a Vegetarian McFeast burger on its menu.

McDonald's is famous for tailoring its menus to international markets, and vegetarian options are much easier to find in restaurants some parts of the world compared to others. In India, where one fifth of the population is vegetarian, customers can order the McAloo Tikki Burger, made from potatoes and peas, or a McVeggie sandwich.

[h/t Today]

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