The Smoke Detector Principle: The Evolutionary Advantage of Overreaction

Notes on anxiety, depression, and borderline personality disorder

You read this newsletter so you’re almost certainly a person of above average intelligence. Intelligence correlates with educational attainment and occupational success.

And people with the highest levels of educational attainment have higher anxiety than people with lower educational attainment. People in white-collar professional occupations also have higher scores for anxiety than those in blue-collar occupations.

Anxiety is, generally speaking, a first-world problem. A 2017 study in JAMA Psychiatry, which used data collected from nearly 150,000 adults in 26 countries, found that generalized anxiety is far more common and more severe among people in wealthy countries.

Considering that half of American adults under the age of 30 report feeling anxious all or most of the time, anxiety is something worth learning more about.

Moreover, the proportion of Americans diagnosed with clinical depression at some point in their lifetime reached an all-time high in 2023, at 29%. Depression can encompass suffocating sadness, an inability to feel pleasure, and lethargy that makes the smallest tasks seem insurmountable.

The percentage of U.S. undergraduates diagnosed with depression and anxiety doubled between 2009 and 2019. Given these findings, depression is something worth learning more about too.