Why does incapacitating mental illness exist? Why would nature consistently produce people born with debilitating health problems? Is nature so cruel and unfair that it curses some people while blessing others? Perhaps. But perhaps there’s an alternative interpretation.
We humans are made up of a collection of traits.* Contrary to early scientific thought, we now know that these traits are rarely useful or dysfunctional on their own. When things go wrong, it’s less about dysfunctional traits and more about dysfunctional combinations. A useful analogy is to think of human characteristics as ingredients in a kitchen. Some combinations taste foul and others sublime; some are subtle, and others can easily overpower. And we humans are the final dishes.
The trouble with this model is that at Bistro Homo Sapien the menu is enormous. Humanity’s kitchen must stock such an immense array of ingredients that inevitably there are going to be some unpleasant combinations.
Take for example people who have difficulty filtering out the mundane elements of their surroundings (latent inhibition). These people struggle to block out irrelevant details, and as you might imagine, this can be hugely problematic. In fact, this dysfunction is associated with an increased risk of schizophrenia—but not always.
For some people, a difficulty to filter combines with another trait—high IQ—to produce a high-functioning creativity. Rather than being overwhelmed by extraneous inputs, these creatives can channel their access to additional information in positive ways. Dysfunction, then, is a matter of compatibility. (Oversimplifying: Low Latent Inhibition × Low IQ = Incompatible Schizophrenia; Low Latent Inhibition × High IQ = Compatible Creativity)
So perhaps human biology is unfair. Although, it may be helpful to remember that, “Nature optimizes for the whole, not for the individual.”2 The mechanism that allows some trait combinations to flourish requires others to falter. In this light, even debilitating mental illness can be seen as a positive—an example of the rich, robust, and beautiful diversity of our species.
* “Traits” is used here as a general, catch-all for observable human characteristics. A person could be described as “naturally shy,” for example. In a more scientific description, we could use phenotype; however, this genetic term often fails to reflect the combination of life-experience, genetic predisposition, and environmental factors that combine to create what most of us colloquially refer to as human traits.