Is Depression Man-Made?
Depression is the unsurprising consequence of damaging the brain's engine
In 1983, Daniel Everett was back in the Amazon rainforest after having spent years learning the unique language of the Piraha people. His ultimate goal was in fact to convert them to christianity. One evening after dinner, he decided to tell the Piraha the story about why he chose to accept Jesus. Daniel had talked before about how he used to drink, do drugs and was a very unhappy person and christianity helped him through this, but this night he wanted to really open up and tell them something very personal. He shared that in fact his Step Mother committing suicide was what lead him to Jesus. When he finished, the Piraha burst into confused laughter saying:
“She killed herself? Ha ha ha. How stupid. Pirahãs don’t kill themselves.”
From our perspective, laughing at a such a tragedy is incredibly cruel. From the Piraha perspective, clinical depression is such a foreign concept that it seems silly.
Daniel Everett has said that over his decades with the Piraha, he’s never seen any evidence of depression. Similarly, in the Mla Bri Hunter Gatherers of Thailand, suicide was unknown until 2005 or so when they were transitioning into settlements.
So could depression be a man-made thing?
In Chapter 8 of the 2022 textbook Evolutionary Psychology, they argue that clinical depression is a disease of modern lifestyle. Anthropologists who examined various hunter gatherer societies report that the incidence of depression is exceedingly rare in these populations. For example, a 1986 study of the Kaluli people of New Guinea found that only 1 in 2000 people could be considered depressed. Yet as of 2023, 1 in 6 American adults have depression and 1 in 3 have experienced it at some point in their lifetime.
In fact, evidence suggests that the more modernized a society becomes, the higher the rates of depression. You’d think depression would be totally figured out by now - since the 1950’s, tons of research has been done into various treatments for depression. Yet there’s a paradox, despite more and more treatment, there’s not less depression - there’s more nowadays. Use of antidepressants has quadrupled since 1988 … but depression rates just keep going up.
To see the big picture, we need to rewind a lot.
Next stop: 600 BC
Depression has been associated with the brain illness epilepsy for a very long time.
Take a look at this 2600 year old ancient Babylonian Tablet. The tablet is discussing epilepsy. The Babylonians were quite familiar with the disease, they recorded all kinds of different types of seizures. What was the cause of these epileptic seizures? Well - it’s in the name. It is the result of someone being seized, being taken hold of by an evil spirit. Seizures are also documented in the Bible and attributed to demonic possession. Various other mental ailments have been attributed to spirit possession in the Bible. The symptoms of King Saul’s “evil spirit possession” actually sounds alot like clinical depression.
Evil spirit possession sounds silly, but what’s interesting is how Jesus recommended you cure these demons. In Mark 17:21, he says the way to drive out demons is through “prayer and fasting.” On the other hand, Hippocrates correctly identified that epilepsy was a problem of the brain, not the spirit. It was recorded in the hippocratic collection that epileptic seizures could be stopped by completely avoiding food. Today, it’s well known that indeed, fasting - eating nothing will dramatically reduce seizures in most people with epilepsy.
But what does epilepsy have to do with depression, and what does this have to do with food?
Well, the key to the link may lie at the bottom of the ocean and at the top of mountains.
Breathing at a high altitude is hard. Breathing underwater is REALLY hard. Yet, weirdly enough, if someone fasts they can hold their breath longer, which would be really useful for freediving.
Freediving is an intense sport where people dive down 20 to 60 feet without any scuba gear - they just hold their breath.
A 2014 study took elite free divers and tested how long they could hold their breath after eating a 500 calorie meal and after not eating for 13 hours. So basically they finished their dinner the night before and did the breath hold before eating breakfast. Now, a normal person can hold their breath for maybe a minute. After eating their small meal, the free divers held their breath for an average of 3:51 . However after fasting for just 13 hours, they held their breath a whole 50 seconds longer - a total of 4:41 seconds. Another 50 seconds is a huge difference, especially for elite divers.
Now, another study found that just changing the diet of mountaineers somehow allowed their bodies to utilize more oxygen when put in a low oxygen environment. This would be very useful when climbing a mountain because the thin air at high altitude is a challenge for climbers due to the low oxygen.
OK, so fasting rapidly reduces seizures and it happens to make the body perform better when deprived of oxygen. Research suggests that when a seizure is happening, the oxygen concentration of certain areas of the brain can rapidly drop. And oxygen in the brain has been found to be dangerously low after an epileptic seizure as well.
Further, studies suggest that living at high altitude where there is less oxygen increases the risk of developing epilepsy. High altitude also increases the risk of depression* and anxiety.
*Might be more likely if you move from a low altitude to a high altitude region. (See also)
There are all kinds of clues suggesting that low oxygen has something to do with depression and anxiety. The brain gets very anxious when it senses that there is no oxygen coming in.* If you want to feel anxious right now - just hold your breath as long as you can. The feeling that you need to breathe probably doesn’t feel very good - a lot like anxiety. In fact, the physical symptoms people experience when they have altitude sickness are nearly identical to the physical symptoms of a a panic attack.
*The signal to the brain that you’re being deprived of incoming oxygen is actually the buildup of carbon dioxide in the blood.
Hold up, it’s not like all people with depression, anxiety or epilepsy are living at high altitude. So what’s going on?
Well there are other situations that lower oxygen in the body like sleep apnea - this is where people aren’t just snoring, but they stop breathing at night and reduce the oxygen available to the body and brain. I got a sleep test once to see if I had sleep apnea and I had to wear a device that monitored my blood oxygen levels.
Sleep apnea is well known to be strongly linked to depression and anxiety …and it increases the risk of seizures.
Here’s another interesting one - people with diabetes have 2 to 3 times higher risk for depression. And this paper explains that parts of the body in people with diabetes are commonly found to be low in oxygen.
Let’s look at one last connection between oxygen and depression before we examine what fasting and our modern diets have to do with all of this.
Keep reading with a 7-day free trial
Subscribe to Joseph Everett’s Newsletter to keep reading this post and get 7 days of free access to the full post archives.