Shouldn’t evolution end mental illness?


By David Joel Miller.

Why are there so very many different genes involved in mental health?

evolution and mental illness

Is Mental illness a survival mechanism?
Photo courtesy of Pixabay.com

Clearly, there were lots of lifeforms on the earth in the past that are no longer around. Without getting sidetracked here by the whole question of evolution or creation or some variant of the two, one still has to wonder how all those things which are calling mental illnesses arose. And why do mental illnesses still exist?

Every additional study I read tells me that someone has identified a gene they believe may be involved in creating or exacerbating a condition we are calling a mental illness. If they haven’t found that gene then they are suggesting one must exist and remains to be found.

This raises the question: “Why are there so many of these mutations?”

That makes me wonder if all these conditions we are calling mental illnesses are of recent origin or did they at some time in the past have some evolutionary advantage. If mental illness did not serve some purpose in the past, why does it still exist?

Ancient literature, the Bible and other writings mention things like alcoholism, drunkenness and some people with impaired reality testing who would in past times have been described as “mad.”  This was Mad as in insane or mentally ill not mad as in uncontrolled anger.

Shouldn’t natural selection be reducing not increasing the number of mental illnesses?

We know that mental illness shortens the life span, the mentally ill live fewer years than those without a diagnosable illness. Over time there should be fewer and fewer of the mentally ill left to reproduce. That would make some sense unless there was at some time, current or past, some advantage to what we now call a mental illness.

Humans now live longer and in larger clusters.

Some authors have suggested that many of the diseases we are now most concerned about, heart conditions, cancers, and diabetes are largely the result of humans living longer than before. When the average lifespan was 30 or 40 years, few people lived long enough to get those old-people diseases. See Sapolsky’s “Why Zebras Don’t Get Ulcers” for more on this topic.

So people live longer now and they also are living more and more in large industrial cities. Crowding of the sort that happens in cities can cause stress and changes in behavior. Is it possible that humans are mentally and emotionally un-adapted to live in large city masses?

There has been an avalanche of children getting mental health diagnosis.

We used to think that childhood was essentially a happy time and then you grew up and had to work. Only back then most children did not grow up, they died. So the more we look at the childhood prevalence of things we call emotional disturbances the more of these things we find. ADHD in elementary school girls is up 600 percent. Depression is more common than expected in children. Suicide rates of children are occurring in younger children and becoming more common.

Are mental illnesses ancient survival mechanisms?

What if some of those things we call mental illness helped people survive in the times when most people lived in rural areas, forests and jungles even, and some of these things use to be good things, but they are no longer as helpful in modern industrial situations.

How could some anger be a good thing?

Anger and its link to the fight or flight responses in the brain appears to occur in all the animals with a brain stem. For creatures of any kind that primitive response to threat can keep you alive in times of hunger when you need to fight for the food. Getting angry and fighting can also keep you from becoming that food.

Killing to preserve your life and your food supply makes sense when you live in the woods and that is a mountain lion out to eat you. That same anger mechanism is less helpful when someone cuts in line in front of you at the supermarket. Get angry and hit someone there and you may be the one getting carted off to jail or the psych hospital.

Why do bipolar people reproduce?

One of the characteristics of bipolar disorder is hyper-sexuality. This same driven sexual behavior can be seen in drug addicts also. Sexual “acting out” as it gets called, can get people with bipolar disorder in trouble with their family and their mates.

People, most of them, who are faithful to their mates get more sex on a regular basis and they tend to live longer than those who have lots of sexual partners. For someone in extreme danger who might get eaten at any moment being hypersexual may not improve your survival but that increased number of offspring may have helped humans expand their population at the expense of other animals.

What is good for the population as a whole is not always good for the individual person and vice versa.

Could depression have been an asset in the past?

Some of the characteristics of depression, the atypical type, are eating everything in sight and then sleeping as much as possible. This is a great strategy if you live in an ice age cave where food is unreliable and you need to conserve energy.

Eating everything in sight and sleeping all day does not work so well when you have a job to go to every day.

The point I am making is that many of the things we think of as “mental illness” may have been functional in the past. Some of these things that are getting labeled illnesses are more “maladaptations.” Even the bears don’t get to hibernate the way they used to.

ADHD may have saved lives.

One of the characteristics of this thing we are calling ADHD is restlessness and hyperactivity. This is useful if you need to outrun run a lion. The more you run around the stronger your legs get. Being fast on your feet keeps you from getting eaten or killed in some situations.

Today children need to stay put and not move to keep the teacher happy. That ancient part of the brain is telling them to run, play and move fast. It may take a long time for the human brain to catch up with the move from the woods to the big city.

Just my speculation on how these things we call mental illnesses may at points in the past have been more adaptive than they are today.  What do you think about this?

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For more about David Joel Miller and my work in the areas of mental health, substance abuse and Co-occurring disorders see the about the author page. For information about my other writing work beyond this blog check out my Google+ page or the Facebook author’s page, up under David Joel Miller. Posts to the “books, trainings and classes” category will tell you about those activities. If you are in the Fresno California area, information about my private practice is at counselorfresno.com. A list of books I have read and can recommend is over at Recommended Books

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