What Causes Mental Illness?

May 16, 2022

If you or someone you love has ever struggled with a mental illness or poor psychological well-being, then you've probably asked yourself why. It's human nature to want to know why. Why did this happen? Why did they do that? What caused that? Why are things this way?

Today, we're going to try to answer those questions: What causes mental illness? Why do some people struggle with their mental health? 

The short answer is...it's complicated. The long answer is that there is no one causal factor. The path toward mental illness is windy and complex. It's like a baking recipe that requires several ingredients, in the right combination, to get that specific outcome.


Factors that cause mental illness

In the world of clinical psychology, we understand mental illness, psychological disorders, and poor mental health using what's called a bio-psycho-social model. 

Think of it like a stool with three legs. You need all three legs for the stool to balance. In the same way, we must consider three "legs" when it comes to understanding mental illness.


Biological factors that impact mental health and well-being

The "bio" part of bio-psycho-social refers to our biology, and this level plays a huge role in how our brains and minds work. We know that there tends to be a genetic loading for a lot of diagnosable mental health conditions. That said, it's not as simple as you get the gene and, boom, you're guaranteed to have the disorder. That's because it's not just one gene. There are tons that contribute to mental health. It gets even more complicated as we consider the emerging field of epigenetics, which looks at how genes can be switched on and off. 

Yep. You read that right. Things we do or experiences in our environments can literally turn certain genes on or off. I told you it's complicated.

Biology includes more than just the genes we inherit, though. Biological factors that we know have a very real impact on the development of mental illness or the worsening of symptoms can include things like inflammation in the body, heart rate variability (essentially how long it takes your nervous system to settle back down once it's been activated), and hormones and chemicals in our brains. In addition, lack of sleep and exercise, which affect our biology in huge ways, are also linked to mental illness.


Individual factors in mental illness

As we consider habits that impact our biology, we start to cross over into the second leg of the stool: our individual psychology. This includes the way we think, our behaviors and habits, the way we navigate our emotions, our personality, unique learning histories, mindset, and worldview. For example overly pessimistic or negative thinking habits up your chances of developing depression. 

The way we interpret and respond to events in our lives can vary widely from person to person, and those tendencies can impact the development of mental illness or serve as protective factors. 


Social influences on mental illness

We don't exist in vacuums, though, and we are shaped by our relationships and social environments. Our families, schools, and communities influence how we think and behave, how we relate to others, and even the habits we develop. What's more, our relationships and environments and the experiences that those bring with them, especially in childhood, can impact the way our brains develop circuitry (again, I told you it was complicated!).

As kids, we look to the adults around us to model good (or bad) coping, to show us how to operate in the world, and how to view ourselves. And if these relationships are toxic or abusive, they can have a detrimental effect on us, impacting how our brains develop (biology) and how we see ourselves and others (psychological). 


A complicated web

Our biology and psychology, situated firmly within our relationships, social networks, and interpersonal contexts, come together in ways that may result in mental illness or mental health. As we consider these different levels that can all contribute to mental illness, we also have to consider interactions among them. That is how things on one level impact the others. Said another way, the lines between these levels are pretty fuzzy. For example, a personal habit of scrolling on instagram at night ("psycho" level) causes disrupted sleep ("bio") that can make you vulnerable to anxiety and depression. A supportive, accepting caregiver who models courage can offset a genetic loading toward anxiety. 



As we consider the causes of mental illness and poor psychological health, I want to be very clear on a few things. First, there is no place for blame here. While, yes we play some role in our habits that may contribute to mental health, it's not helpful (and often not even accurate) to point the finger and assign blame. "If you'd just XYZ, you wouldn't be struggling!" Please don't say that to yourself or anyone else.There may be things that could improve the situation, but it so rarely a single factor contributing the picture.

Similarly, our parents or certain life events may very well contribute to difficulties, but again, unilaterally placing the blame one person or one cause is like trying to paint a beautiful landscape with only the color blue. You need a lot more than blue for the picture to come together. To illustrate, trauma can be a path toward mental illness...but it isn't always. Certain bio-psycho-social factors can protect against the ill effects of trauma or change the trajectory over time. 

Second, mental illness is NOT a weakness. It is not a sign of any deficit in character or intellect. We don't judge people for allergies or cancer, yet we somehow want to treat mental illness like it's a different beast. 

It's not. 

It's a complicated health condition. Period. 

Finally, I encourage you to set aside any notion that having a mental illness means that you can not live a bold, beautiful life. There will be challenges and you will struggle with some things that others may not. And yet it doesn't have to be a prison sentence. While many diagnosable conditions are not curable, per se, there's a lot we can do to improve functioning and our life experiences. With the right know how and habits, and the right interventions, we can learn to thrive with mental illness.


“There is hope, even when your brain tells you there isn't.” 
—John Green, Turtles All the Way Down


Boundaries: A Key to Psychological Freedom

On Thursday, Peak Mind is speaking at the first ever Humanity at Work conference. Our topic is a deep dive into boundaries - why they're important, what makes them hard to set and maintain, and how to get more comfortable and effective in doing so. There's still itme to get your ticket to this virtual event. See you there!


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