Depression affects more than 300 million people worldwide; that’s almost 4% of the world’s population. Depression and suicide rates are also increasing, specially in Millennials and Generation Z. There are a lot of factors that can affect this including diet, exercise, social media, politics and even the lighting of a room, but much of it is physiological.

Consensus dictates that depression arises due to “monoamine hypothesis”. It says that depressed people have a shortage of serotonin and norepinephrine. So the vast majority of treatment focuses on fixing this imbalance through anti-depressants. This method doesn’t always work however.

According to Yumiko Saito and Yuki Kobayashi, neuroscientists at the Graduate School of Integrated Arts and Sciences at Hiroshima University, 30% of those given anti-depressants do not experience any effects. This calls for a new drug or a new reason for the cause of depression. Results of a new study by them have been published in the journal Neuroscience.

They focus on a protein called RGS8 which is involved in movement and the regulation of mood as well as controlling the hormone receptor MCHR1. When the latter is functional, it regulates sleep, feeding and emotional responses. Previous studies had suggested that low levels of RGS8 had increased depression in individuals. However, there were never any tests done.

This study had mice carry out a forced swim test. Some mice were given increased doses of RGS8. Those same mice had lower levels of immobility (time spent not swimming) than those not given RGS8. Immobility is seen as a sign of depression. This depression was not related to monoamines at all, it was related to MCHR1.