What is depression?
The World Health Organization predicts that in 2030, depression will be the main contributor to the global burden of disease. What is causing this, and what can we do about it?
In this article, I will make the case that depression is a biological disease, and provide arguments for why realizing this can be beneficial for treatment. Before you label me as a biological essentialist, let me explain. After all, I’m actually a sociologist. What confuses many people about the whole «nature vs nurture» debate, is that they think something can be either or, when in fact everything is heavily influenced by both factors.
Bodily response to (psychological) pain
Many biologists and psychologists claim that there is a 50–50 contribution from genes and environment when it comes to human characteristics. Robert Plomin, a psychologist at King’s College, claims that genetics is the most important factor for determining in what way people differ from each other. I agree, and would add that environments in turn determine how the different genes express themselves, and in that way are essential for the outcome of individuals. This means that changing the environment can’t create equal outcomes, because of genetic differences, but it can in fact make every individual live up to their full potential, which is a great thing.
For example, there is evidence that stress can cause a drop in IQ by about 10–15 points. Other strong emotions also have the power to infuse how the brain operates, like love, as most of you probably have experienced. But few people walk around in a chronic love-induced brain fog. Stress on the other hand, is prevelant and often chronic, which leads to depression.
Your body creates a biological response when it’s subjected to harmful stimuli, for example pathogens or physical trauma. This biological response is called inflammation. When people have an infection and when they are depressed, the behavioral response is pretty similar. They are deprived of energy, the mood drops, and they isolate themselves. Research shows that loneliness causes inflammation in the brain, in the same way that a virus can cause inflammation in the body. The reason is simple: both loneliness and viruses are recognized by the body as harmful stimuli. The behavioral response mentioned should be interpreted as a sign that something is wrong.
Don’t blame the genes
Some people are more prone to depression than others due to their genes, but nobody is hardwired to live a life chronically depressed. Gary Marcus, neuroscientist at NYU, explains it like this:
Nature bestows upon the newborn a considerably complex brain, but one that is best seen as prewired, flexible and subject to change — rahter than hardwired, fixed and immutable. Nature provides a first draft, which experience then revises. “Built-in” does not mean unmalleable; it means “organized in advance of experience”.
The triggers of depression, then, are environmental. But why are some genes associated with depression? Could there be an evolutionary cause for this?
While living as hunter-gatherers, as we did for 90% of human history, humans were most likely to die of trauma. Diseases took over the role as the greatest threat to human life when agriculture was invented about 12 500 years ago, which is a short period of time, evolutionarily speaking. This led to the growth of bacteria, often transferred from farm animals, that could rely on a high population density to thrive.
8 of the top 10 genes associated with depression also have some sort of immune or inflammatory function. What this means, is that depression could be a way for the body to respond to injury. For example: if you are wounded in battle or infected by a virus, the behavior which is also created by depression, isolation and inactivity makes perfect sense. Not only is the body better suited to use energy more efficiently, which is important to respond to the harmful stimuli, but it also minimizes the risk of infecting other tribe members.
If you are lonely, the body may respond as if you were injured. It is actually not a mistake.The body and the mind are not separate entities. One affects the other, and vice versa, often creating a feedback loop. If the body’s response to psychological damage is similar to the response to physical damage, we can use this knowledge to explore solutions. Today, we are physically healthier than ever, and have a better understanding of treatment of physical trauma and infections than ever before. I would argue that we don’t understand depression nearly as well.
Have you ever wondered why the same drugs that are best for numbing physical pain also works best at numbing psychological pain? Benzodiazepines, like Xanax, and opiates, like heroin, are prescribed by doctors for physical injuries, but also work wonders for depressed and anxious people. This is because the drugs act directly on the central nervous system and decreases pain, both physical and psychological.
Depressed people have up to a 50 % increase in inflammatory markers in their bodies. If depression is a bodily response to handle harmful stimuli, there are a lot of things we can do. Even though we live longer, our modern lifestyle has a lot of elements that cause inflammation.
- Diet and exercise: We are more overweight than ever. High consumption of sugar causes not only weight gain, but also inflammation. This is also true for carbohydrates in general, which we eat more of than ever before. Also, fat tissue will itself cause inflammation. Getting slimmer is just one way exercise contribute to eradicate depression. Therefore, if we get rid of inactivity, which sadly is widespread in developed countries, depression will decrease. Another important factor is the widespread use of vegetable oils, like sunflower oil, which disturbs the body’s balance between inflammatory Omega-6 fatty acids and anti-inflammatory Omega-3 fatty acids. In other words: eating french fries can actually contribute to depression.
- Loneliness: Social psychologist Jonathan Haidt argues that teens who spend the most time on social media, are the most lonely. Since 2010, depression has risen dramatically among young people. The suicide rate for teenage girls is up 82 %, while the number is 34 % for teenage boys. Haidt thinks there’s a direct connection to social media use, which causes people to spend less time actually interacting with their peers.
- Crisis of meaning: Religion is on the decline. This is in my opinion not bad in and of itself, but there may be positive elements of religion that would be beneficial to incorporate more in today’s secular age. First and foremost: Community and purpose. A healthy society needs to provide it’s members with common goals to strive for, and a sense of common belonging, which in turn leads to a strong community. Research shows that there is a correlation between how much people feel belonging to a religious community and how generous and happy they are. In my opinion, this aspect can be improved in today’s modern, secular societies.
There are more elements to this problem, but it seems that a lot can be done by fixing nutrition, spending less time on social media and creating stronger communities. While it is essential to understand the genetic component of depression, we should look to the environment for solutions.
#psychology #mentalhealth #biology #depression #crisisofmeaning #diet #socialmedia