I recently wrote an article about the link between being a writer and having depression, as I’m so aware of the effect my mental illness has had on my writing and life in general. While researching for the article, I came across the idea that it stems from the link between a higher IQ and depression.

Relating writing to depression had been enough of a leap for me, as this was something people kind of chose to do, despite the enjoyment being either present or not, but intelligence was a core trait, something buried deep in our DNA and sense of self. Could your level of intelligence really cause you to suffer from a mental illness, and how would we even go about proving this?

The Mensa Study

Mensa is the largest and oldest high IQ society in the world and requires members to have an IQ in the top 2 percent. If you were to look at that in terms of the average intelligence test, this would correspond to an IQ of 132 or higher. The average IQ of the general population is about 100. So you could say they are pretty smart. There are 134,000 members, and their headquarters is in Caythorpe, United Kingdom.

Researcher Ruth Karpinski and her colleagues saw an opportunity in this high IQ society, using it to measure the rumoured link between a high IQ and an increased risk of mood disorders. They provided members with an extensive survey that covered mood disorders (dysthymia, bipolar and depression), anxiety disorders (social, generalised and obsessive-compulsive), autism and ADHD. The survey also covered non-psychological illnesses, such as environmental allergies, autoimmune disorders and asthma. Each respondent had to report whether they had ever been formally diagnosed with one or more of the disorders, or even if they suspected they suffered from it. The latter is an essential aspect for several reasons. Firstly, as the stigma surrounded mental illness can prevent individuals seeking treatment and official diagnosing. It could also be that they have struggled with depression but not to the extent of seeking help, which is not recommended but does occur. The lack of a formal diagnosis should not undermine the severity of a condition. However, to play the devil’s advocate, we could also use this to question the legitimacy of the answers. Would an individual, especially one assured enough of their own intelligence to be in a high IQ society, perhaps overestimate their ability to self-diagnose? Read into symptoms that would not clinically be sufficient for one of these disorders. Food for thought, but we’ll continue.

There was a return rate of almost 75%, which is incredibly high for survey data. Karpinski et al. then compared the results of the 3,715 respondents to the national average. They found the most significant difference in the statistics for mood disorders and anxiety disorders. For 26.7% of the sample reported that they had been formally diagnosed with a mood disorder, and 20% with an anxiety disorder. Given that national averages are 10% for each category, this is significant. The other conditions also showed higher precedents, but at a far smaller difference. The only other diagnosis with higher results was the prevalence of environmental allergies, which was over triple the national average with 33% versus 11%. This may explain the stereotypes regarding intelligence (geekiness) and allergies. As an allergy sufferer, I’ll take it as a compliment.

Why are people with a higher IQ more likely to be depressed?

Karpinski et al. proposed the hyper brain/hyper body theory, which considers high intelligence to come with psychological and physiological “overexcitabilities”. An overexcitability is an unusually intense reaction to an environmental threat or insult, everything from a sudden noise to a confrontation with someone. A physiological overexcitability would revolve around the body’s response to stress, while a psychological overexcitability includes a heightened tendency to ruminate and worry.

This all sounds well, but how would this work in practice? Take an everyday situation, like being scolded by your superior. The theory is that a higher intelligence individual would fixate on the disapproving comment and worry about potential adverse outcomes. Their body would go into a fight or flight mode, inducing stress. But someone less intelligent would move past the situation quicker, and not feel consequences extending past the moment. You could see how such reactions could breed a habitat for depression, anxiety or another disorder.

There are several other routes we could consider when looking at this question. Perhaps the higher IQ leads an individual to fixate on world or society issues more, feeling ‘weltschmerz’ for the imperfection of the world. This is a heavy burden to carry and would leave them vulnerable to emotional turmoil.

Some have suggested that introversion is linked to a higher IQ, and this could leave room for social anxiety or other issues. But we must remember that this is yet to be confirmed, as both extroverts and introverts can struggle with social anxiety or other mental illnesses.

But can we rely on the results of this study?

This study alone is not enough to determine a link between a higher IQ and mental illness. Firstly, because it is only a correlation. It could be that the individuals who join Mensa have more in common than a higher IQ; they may be more occupied with intellectual pursuits and spend less than average time on social interaction and physical exercise. Both of these are beneficial for psychological and physical health. This would mean that higher IQ does not cause the diagnosis of a mental illness or the other way around.

Aside from another cause for the higher rates of mental illnesses in this group, we could also question whether this group actually does have that increased rate. One could ask if the individuals are just more aware of their mental illness and sought out a diagnosis, while individuals from a differing IQ may not recognise/label the disorder as quickly. They may not recognise their depression or anxiety as the disorder that it is, and thus claim not to have a mental illness. Furthermore, one could wonder if mental illnesses are generally more accepted in highly educated groups, suggesting that stigmatisation plays a role in this.

Conclusion

While the results of this study are intriguing and prompt many questions, they are not enough to determine a link between a higher IQ and depression. There are too many other variables to be considered and ruled out. There is a risk when linking characteristics and traits to depression or other disorders. There is the risk of a self-fulfilling prophecy, assuming individuals or yourself will develop the disorder and thus breeding the symptoms of it. But I also see a risk in whittling the disorder down into an oversimplified ‘cause’. By doing that, we undermine the struggle of the individual and lay blame on one aspect. Mental illnesses are not the result of just your biology or your environment, they are a complex web of both elements. Labelling one trait as the reason makes it seem like just as simple a ‘solution’ could be made. That isn’t the case; it is a long road and involves so many factors, you can try your best and still struggle. We shouldn’t offer false hope, but also not the pessimism of blaming a biological trait that you could never suppress. We should approach each case as unique, learning through studies such as the Mensa study, but staying aware of their limitations and lack of generalisability.