Depression affects approximately 322 million people across the world, or approximately 2.5 percent of the world’s population, yet only half of those afflicted have been able to benefit from existing treatments. In this video, Inverse takes a look at a new study that might give us an explanation as to why that is.

The short answer is that our understanding of depression has been incomplete. The common knowledge for some time has been that depressed people have lower levels of serotonin and norepinephrine in their brains, which trigger symptoms of depression due to a chemical imbalance. Ninety percent of antidepressants on the market today operate off of this assumption. Yumiko Saito, Ph.D., and Yuki Kobayashi at the University of Hiroshima, the scientists behind this new study, set to be published in the July issue of Neuroscience, are attempting to expand our outlook on the disorder.

According to Saito and Kobayashi, “Thirty percent of people on these drugs do not experience an effect. Obviously, we need a new drug! We need another explanation for what could cause depression.”

depressed girl
Only half of people treated for depression find current drugs effective.

How it Works

This explanation comes in the form of a protein called RGS8. Saito and her team had previously discovered that RGS8 controls MCRH1, a nifty little hormone receptor that helps regulate mood, eating, and sleeping patterns, aka a volatile blend of factors that, if tampered with, could easily trigger depression.

RGS8 can affect mood and body control on its own, and it can also inactivate MCHR1, suggesting that higher levels of RGS8 would increase the likelihood of depression.

After running some tests on two sets of mice, one genetically engineered to have more RGS8 in their system, they found that the mice with more RGS8 actually displayed fewer depressive traits and seemed to have more drive.

mice rat mouse lab depression protein hormone rodent
Scientists at Hiroshima University worked with mice to better understand RGS8's effect on depression.

They also noticed when examining the brains of the mice that they had longer cilia in the regions of the hippocampus where there was a higher concentration of RGS8. Cilia are small organelles that help with cellular communication, but if they’re not in good shape, they’ve been linked to all kinds of ailments, like obesity, kidney disease, and retinal disease, which suggests RGS8 might be the key to longer cilia.

Depression is an awful companion, and the brain’s such a complex piece of machinery that we’re still only getting started with unpacking its depths, but Saito’s team hopes that RGS8 will be “a promising candidate toward the development of new antidepressant drugs.” Whether those only end up working for a small portion of people with depression remains to be seen, but considering that all the drugs prescribed for depression since the ‘70s have been targeted toward serotonin-related issues, this new focus on RGS8 could be the equivalent of finding a new wing in a house you’ve been living in for decades.


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