Books: Good Reasons for Bad Feelings: Insights from the Frontier of Evolutionary Psychiatry

In 2019, one in every eight people, or some 970 million people globally, were living with a mental disorder.¹ This figure increased rapidly and substantially as a result of the COVID-19 pandemic, and global prevalence of anxiety and major depressive disorder (which constituted the most common mental disorders) increased by 26% and 28%, respectively, in just a single year.¹ In England, a study of 8086 adults aged ≥16 years using Health Survey for England 2019 data found that 5.1% of GP consultations were for mental health problems, and 11.5% were for a combination of physical and mental health problems.² Even within my own short career in general practice, I have noticed a clear increase in the proportion of my appointments that deal with anxiety and depression. Many other GPs have recognised a similar trend,^3,4 and many have spent at least some time pondering the cause of this phenomenon.

In his 2019 work, Good Reasons for Bad Feelings: Insights from the Frontier of Evolutionary Psychiatry, Randolph M Nesse attempts to answer this question from a perspective that I had not previously encountered — that of evolutionary medicine, specifically evolutionary psychiatry. Rather than view each mental disorder as a ‘brain disease’ with an underlying direct cause, Nesse applies an evolutionary lens to understand why natural selection has left humans vulnerable to developing these debilitating symptoms that increasingly lead patients to our doors in general practice. He argues that humans have the capacity to experience deeply unpleasant emotions such as anxiety and depression as they are adaptive for our reproductive success, such as anxiety promoting vigilance in a dangerous situation. He uses the analogy of a sensitive smoke alarm, which might inappropriately sound in response to burnt toast — this low-cost inconvenience is worth the high-value protection that the same fire alarm provides when it alerts us early to a genuine threat. Similarly, anxiety and depression, which harbour adaptive functions, might sometimes be turned on inappropriately as well as in response to situations that resemble those they evolved in — this ‘over-sensitiveness’ constitutes a fitness advantage for our genes (which our emotions evolved to propagate).

This evolutionary perspective of mental disorders offered by Nesse has meaningfully updated my understanding of these conditions. Given the scale of the problem in general practice, wider society, and around the world, the personal impact of this book is such that it is consequently my most important read of the past year. The work is highly accessible to anyone with a basic understanding of Darwinian natural selection and reproductive fitness, which all GPs certainly have. I therefore recommend the book to every GP who consults with patients who report mental health problems, and also to those who are struggling with such problems in their own lives.