What causes mental illness? (Hint: it’s not “thinking too much”)

It’s the million naira question, isn’t it? Where does mental illness come from? In a post I wrote recently for African Hadithi, I described how patients sit in front of me asking if there’s a cure for their illness, and hoping for a concrete answer. I didn’t mention it there, but this is another huge question on the minds of many of the patients that end up in front of me during a typical clinic: “Where did this come from? Why do I have this kind of illness? What caused it?”

The short answer is: “Nobody really knows.”

(If anyone tells you any different, they either don’t know what they’re talking about, or they’re trying to sell you something—and probably something nicely expensive.) (Tweet that!)

The long answer, of course, is this entire post.

I’m sure you’re surprised to hear that we don’t know what causes mental illness. (By “we” I mean all of us who study and practice modern medical science). The question that typically follows is, “But isn’t it due to heredity? Or hard drugs? Or thinking too much?”

(If you’re wondering what “thinking too much” means, you obviously didn’t grow up in Nigeria. That’s a Nigerianism—maybe even an Africanism, I’m not sure—for worrying. I wonder, though, is it possible that our equating mental work with worry a possible reason for our negative view of inllectualism? I don’t know—I’m just wondering.)

Yes, mental disorders can be related to all of those things. And yet, it’s caused by none of them. How does that work? The key is in those two words: “related” and “caused.”

There’s a difference between risk factors and causes of mental illness

People often mix up risk factors and causes. And it’s not just in mental disorders. Take hypertension, for instance. If you asked most people what causes hypertension, they’d tell you everything from excessive eating and excess salt to being overweight and not exercising enough. But none of those are causes, either.

They’re only risk factors.

What’s the difference? Or is this all just semantics?

It’s not, actually. The difference is, causes of a condition are things that will produce that condition when they’re there, but risk factors of a condition are things that increase the chances of a person having that condition. That is, when they’re there, that person is more likely to have it than if they weren’t. But it’s still only a likelihood. It may not happen. And on the other hand, someone who doesn’t have the risk factor at all may end up with the condition.

So you find people who don’t smoke that get lung cancer, while some hard core smokers go their merry way without so much as a cough. That’s because smoking increases the chances of having lung cancer, but it doesn’t actually cause it.

To use an everyday example: you could say someone who drives a car may be more likely to have a car accident, right? But would you say it was the car that caused the accident? Probably not. The cause would have been something else. Maybe the driver was driving too fast—so the cause would be overspeeding. Or maybe he was drunk and reacted too late to a speeding oncoming vehicle—then the cause would be a combination of alcohol intoxication by one driver, and overspeeding by the other. The car itself was only a risk factor.

It’s kind of like that with hypertension and all those things that “cause” it. And something like that with diabetes and “excess sugar.” And it’s similar with mental disorders and all the stuff most people consider to be the causes. More often than not, they are mistaking risk factors for causes. Plus, given all the different types of mental disorders there are, the risk factors aren’t one-size-fits-all either. It all depends.

That said, we do know about causes in medicine—we just don’t know it all…

We do know the causes of a number of medical conditions in general. We know what causes malaria, for instance: Plasmodium parasites transmitted via bites from an infected female Anopheles mosquito. We know that HIV is caused by the eponymous virus, and that tuberculosis is caused by the mycobacterium species. But we don’t know what exactly causes hypertension or diabetes or autism schizophrenia or most cancers or depression.

This doesn’t mean we don’t know anything at all about the cause. For instance, we know that most of these conditions have some genetic basis, and that their appearance in a person is usually a combination of things that happen in them or to them, when they were already prone genetically. But we don’t know the specifics: we don’t always know what genes are involved (although science is getting better at that), and we don’t always know exactly how the other things that happen come together.

Another way to put it is this: we kind of know what factors can contribute to the appearance of a specific health condition in people generally, but we can’t easily say what specific ones they are in a particular person. We can usually identify the risk factors, though. But their presence doesn’t mean the condition will happen. And their absence doesn’t guarantee that it won’t.

This is where it really gets frustrating for most people. I know. I get it. Because it’s like, if you can’t identify the cause, how do you prevent it from happening? But that is just the whole point of rising above it. Science is getting closer and closer to getting to the root of some of the biggest medical questions. But it’s still a long way from an answer for many others. In the meantime, life must go on. A Rise Above It mindset doesn’t think, “How do I relax if I can’t prevent this thing?” It thinks, “How do I live my life to the fullest, whether this happens or not?”

Which do you think is a more productive question?

And if you’re still wondering, “So what are these risk factors of mental illness, anyway?”—that’s just what I’ll be tackling in my next post. I’ve already mentioned some, of course, but there’s more to it, and I’ll be digging in deeper. Catch ya!

Has this helped you a little? Or do you still have any questions? Either way, let me know in the comments! (If the question is too big for the comment, I promise I’ll dedicate a full post to trying to answer it!)

P.S. The medical name for “cause,” by the way, is aetiology (spelled etiology in America).


Published by Doc Ayomide

I’m a medical doctor with specialty training in psychiatry, and I love thinking and writing about what it means to be human.

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