Researchers Believe Depression Once Offered Humans an Evolutionary Advantage

Around 15 million US adults suffer from depression. 6.9 million American adolescents have been diagnosed. The condition is common. 10% of the population may suffer from significant depression sometime in their life. While 30-50% of folks are bound to feel some sort of depressive symptoms at some point. This isn’t relegated to the West.

Depressive symptoms have been found in every culture on Earth and throughout history, though at one time it was called melancholia. Unlike other psychiatric disorders, which are rare, depression is fairly common. According to a San Diego University study, depression across the US has increased significantly over the last couple of decades or so, and people are experiencing more symptoms today too, such as difficulty sleeping or concentrating. Suicide is also at a 30 year high. This matches worldwide statistics.

More people in the world today die from their own hand than in wars and car accidents combined. In the US every age group, other than older adults, has been affected. But women and the middle-aged are particularly prone to suicide. Studies have shown that in most cases, depression or some other disorder was the motivating factor. Researchers blame economic anxiety such as financial trouble and job instability and the inability to save for retirement, or even an emergency.

Another reason may be increased social isolation, as the middle-aged have a high rate of divorce. One study even called it a byproduct of modernity. Here the author wrote, “Modern populations are increasingly overfed, malnourished, sedentary, sunlight-deficient, sleep-deprived, and socially-isolated.” Chronic diseases are on the rise too, and this may influence the depression rate.

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