If a rat is experimentally injected with infectious bacteria, it behaves a bit like I did after the dentist. It withdraws from social contact with other animals; it doesn’t move so much; its sleeping and eating cycles are disturbed.
In short, infection reliably causes a syndrome in animals — called sickness behavior — that is roughly recognizable as akin to the human experience of depression. In fact, you don’t even need to infect a rat to see this sickness behavior. It is enough to inject the rat with cytokines, proving that it is not the germ itself that causes sickness behavior but the immune response to infection.
Inflammation directly causes depression-like behaviors in animals — that is beyond doubt.
Source: The Link Between Inflammation and Depression – Member Feature Stories – Medium
I think this link—if it proves valid—will end up being one of the biggest breakthroughs in mental health in decades. Perhaps equal to the idea that much of our mental functioning takes place in our subconscious.
Last year I created a calculator for determining how depressed you’re likely to be, which also serves as a recommendation engine.
The quote from this article is just remarkable: you can produce depression in animals by challenging their immune systems. Now think of the depressed people you know. How many of them are physically active and eating good foods? How many of them have dental health issues?
In other words, how much of our current depression epidemic is associated with or directly tied to a state of immune system irritation?
Now ask a different question: how many people do you know who eat healthily—with lots of fresh vegetables and very little fast/junk food and who get lots of exercise—are depressed?
There are many causes for depression, so of course it’s possible to be a paragon of physical health and still be depressed.
Anecdotes are not data, but I don’t think I know any. Most are either horrible eaters, obese, sedentary, or all three. The first twenty of these studies I ignored as background noise, but the evidence seems to be adding up. I find it quite fascinating.
I still feel like it’s early in this area of research. And I’m not a doctor so I don’t feel comfortable being certain about these types of things. But here’s what I will say: if you’re in a bad spot, or know someone who is, there seems to be very little risk in entertaining this emerging theory around inflammation.
Consider looking at your diet, dental care, and other sources of inflammation, and then getting serious about exercise.
I think this is likely to (if these studies stand up to scrutiny) become the new standard for not just good health—but good mental health as well.