Randolph M. Nesse, MD, “Good Reasons For Bad Feelings,”  Dutton, 2019, 269 pp.

Dr. Nesse’s book is not just about evolution; it’s also about psychiatry—a discipline the author believes to be in a sorry state. “Like the six blind men each touching a different part of an elephant,” he writes, “each different approach to mental disorders emphasizes one kind of cause and a corresponding kind of treatment. Doctors who look for hereditary factors and brain disorders recommend drugs. Therapists who blame early experience and mental conflicts recommend psychotherapy. Clinicians who focus on learning suggest behavioral therapy. Those who focus on distorted thinking recommend cognitive therapy . . .” And so on. Dr. Nesse has found that, when sufferers can recognize the origin of their conditions not in their own past but in the happenstance of natural selection, it often helps them grapple with their problems.

Hopes were raised that the newly published Diagnostic and Statistical Manual of Mental Disorders, 2013, (DSM-5) would provide better coherence for the diagnostic system than the DSM-4.  A committee of twenty-nine spent a decade on the revision.  But the result created even more conflict and confusion.  (Needless to say, Linda was not on the committee and is not a fan of DSM-5). The crowning blow was the US National Institute of Mental Health (NIMH) abandoning the official DSM diagnoses for mental disorders.  Also, so far the search for finding brain abnormalities that cause mental disorders is not yielding conclusive results.  After decades of research, a specific brain cause has not been found for any of the major mental disorders, except for those such as Alzheimer’s disease and Huntington’s chorea.  (Pg. 8).

Why did natural selection leave us so vulnerable to so many mental disorders?  Pursuing an answer to this is the thesis of this book.  Author Randolph M. Nesse, MD, a founder of the field of evolutionary medicine, uses his decades of experience as a psychiatrist to describe a much-needed new framework for making sense of mental illness.

Why do I feel bad? There is real power in understanding our bad feelings. With his classic Why We Get Sick, (A book I now have on my Kindle but have not yet read) Dr. Randolph Nesse helped to establish the field of evolutionary medicine. Now, instead of asking why certain people suffer from mental illness, Nesse asks why natural selection has left us all with fragile minds.

 Nesse shows how negative emotions are useful in certain situations, yet can become overwhelming. Anxiety protects us from harm in the face of danger, but false alarms are inevitable. Low moods prevent us from wasting effort in pursuit of unreachable goals, but they too can escalate into pathological depression. Other mental disorders, such as addiction and anorexia, result from the mismatch between modern environment and our ancient human past. And there are good evolutionary reasons for sexual disorders and for why genes for schizophrenia persist.

Dr. Neese points out the human body’s unpreparedness to cope with modern environments. When it comes to physical health, this leads to dietary-related scourges such as coronary artery disease and obesity-related illnesses like diabetes: High levels of fats and sugars were rarely available in humanity’s hunter-gathering environments. The same, of course, is largely true for distilled alcohol and a wide array of psychically active chemicals; that’s why Dr. Nesse believes “mismatch” explains much substance abuse.

Then there’s infection. Bacteria, viruses and other pathogens are small, with rapid reproductive rates compared to those of human beings. Their attack strategies thus evolve more rapidly than our defenses do. To cite just one example, the severe psychiatric condition known as Pandas has symptoms that can include obsessive-compulsive tics: The name stands for Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections. If only our immune systems evolved as rapidly as streptococci bacteria, this disease probably wouldn’t exist.

Finally, mental disorders can be influenced by factors directly related to the exigencies of evolution. Complicated things like brains tend to be delicate and easily disrupted, whether by trauma, nutritional inadequacy or other “insults” to the system. And every part of the body has advantages and disadvantages: The immune system is crucial but can be too reactive, leading to autoimmune diseases such as lupus or rheumatoid arthritis. Likewise, responding to threats is a highly adaptive behavior useful to humans, but an over-functioning threat-detection system can manifest as paranoia.

My Notes:

Pg. 12:  Psychology assigns proximate causes to abnormalities, completely ignoring evolutionary connections to the abnormalities.  Both are needed: the proximate causes in each individual and an awareness of the associated evolutionary origins.  See NikoTinbergen’s Four Questions.

Pg. 14:  Diseases do not have evolutionary explanations.  They were not shaped by natural selection.  However, aspects of the body that made us vulnerable to diseases do have evolutionary explanations.  Shifting the focus from diseases to traits that make bodies vulnerable to diseases was the crucial insight that became a cornerstone for evolutionary medicine.

Pg. 15:  Why did natural selection leave our bodies with traits that make us vulnerable to disease?  The question has been debated for millennia as ‘the problem of evil.’  The Greek philosopher Epicurus recognized the conundrum 2,400 years ago; a slight adaptation of David Hume’s terse summary is widely quoted: “Is God willing to prevent evil, but not able?  Then He is not omnipotent.  Is He able, but not willing?  Then He is malevolent.  Is He both able and willing?  Then whence cometh evil?  Is he neither able nor willing? Then why call Him God?”

Pg. 21:  The controversial status of homosexuality as a mental disorder was taken out of the DSM manual when settled by an APA vote in 1974.

Pg. 27:  The rest of medicine recognizes symptoms, such as pain and cough, as protective defenses and carefully distinguishes them from the disorders that arouse them.  In psychiatry, by contrast, extremes of emotions, such as anxiety and low mood, are categorized as disorders, irrespective of any situation that might be arousing them.  This error is so basic and pervasive that it has a name: Viewing Symptoms As Diseases (VSAD).  Reforming psychiatric diagnosis will require recognizing negative emotions as responses that can be useful in certain situations—at least for our genes.

Pg. 34:  Six Evolutionary Reasons Why Bodies/Minds Are Vulnerable To Disease:

1.      Mismatch: our bodies are unprepared to cope with modern environments.

2.      Infection:  bacteria and viruses evolve faster than we do.

3.      Constraints: there are some things that natural selection just can’t do.

4.      Trade-offs:  everything in the body has advantages and disadvantages.

5.      Reproduction:  natural selection maximizes reproduction, not health.

6.      Defensive responses:  responses such as pain and anxiety are useful in the face of threats.

Pg. 53f:  Most approaches to explain emotions represent them as if they were components of a designed machine.  Emotions make more sense when viewed as special modes of operation that increase ability to cope with certain situations.  Emotions are analogous to computer programs that adjust many aspects of the organism to efficiently cope with specific situations and tasks.  So, emotions are best defined as specialized states that must adjust physiology, cognition, subjective experiences, facial expressions, and behavior in ways that increase the ability to meet the adaptive challenges of situations that have recurred over the evolutionary history of a species.

Pg. 57:  Culture influences emotions, just as it influences body weight, blood pressure, and most everything else.  Culture influences what emotions people recognize, the words they use to describe them, the kinds of situations that arouse them and to some extent what emotions are experienced.  However, the capacity to feel emotions is a product of natural selection that we share with one another, and to some extent with other species.

Pg. 85: Mood disorders pose perhaps the most urgent and frustrating medical problem facing our species.  Depression causes more years lived with disability than any other disease.  Suicide is a leading cause of death, increasing by 24 percent from 1999 through 2014 in the US. 

Pg. 101:  The standard way to tell if a drug will be an effective antidepressant is to see if it makes an animal persist in useless efforts.  The Porsolt test measures how long a rat or mouse swims when dropped in a beaker of water.  Rats on Prozac swim longer.  Persisting seems like a good thing, cessation of swimming is designated as a sign of low mood or despair.  But stopping swimming does not mean giving up and drowning, it just jeans switching to a different strategy—like floating with the nose just out of the water.  Rats on drugs that swim longer are more likely to get exhausted and drown.

Pg. 110:  Mood reallocates investments of time, effort, resources, and risk-taking to maximize Darwinian fitness in situations of varying propitiousness.  High and low moods adjust cognition and behavior to cope with propitious and unpropitious situations.

Pg. 133:  Who gets bipolar disorder is explained almost entirely by genetic variations; they account for more than 80 percent of the variation in vulnerability.  If your identical twin has bipolar disorder, your risk is 43 times higher than that of other people. 

Pg. 147:  Substantial evidence suggests that a Mars-sized mass (Thedia) grazed Earth about 4.5 billion years ago, knocking off a piece of our planet that eventually became our moon.

Pg. 161:  For most of the twentieth century, biologists assumed that cooperative tendencies evolved because they were good for groups.  This was debunked in 1966 when George Williams pointed out that especially altruistic individuals would have fewer offspring than others, so alleles for altruism would be selected out.  Then Richard Dawkins published The Selfish Gene with the idea that our brains were shaped to get us to behave in the interests of our genes, not our health.  

Pg. 176:  Social anxiety is overwhelming common because natural selection shaped us to care enormously about what other people think about our resources, abilities, and character.  This is what self-esteem is all about. 

Pg. 187:  The chair of nearly every major psychiatry department used to be held by a psychoanalyst.  They have all been replaced today by neuroscientists.  Purged is a more accurate description.

Pg. 189:  That mechanisms outside of consciousness guide behavior isn’t surprising.  Bacteria and butterflies get along just fine without anything like human consciousness.  Human consciousness involves manipulations of models and comparing the likely outcomes of alternative strategies without the risks of actually doing things. 

Pg. 221:  The obesity epidemic in the US began in 1980.  Many things began to change about that time, including more sedentary jobs, fast food, new processed foods high in fat and sugar, artificial sweeteners, antibiotics, and mass media. 

Pg. 235:  Substance abuse takes a staggering toll.   In the US, 30 percent of adults have at some point qualified for a diagnosis of alcohol abuse.  In 2015 8.4 percent of men and 4.2 percent of women in the US had an alcohol use disorder and 10 percent of the population used illicit drugs.  Worldwide more than a billion people are addicted to nicotine.  In the US the smoking rate has decreased to 20 percent of adults, but smoking still kills 480,000 Americans each year, nearly five times as many as alcohol. 

Pg. 238:  Most chemicals that give humans a buzz evolved to disrupt insect nervous systems.  If our brains used different chemicals, we would not be so vulnerable.  However, we have common ancestors with insects.  It was about 500 million years ago when our ancestors split off from the arthropod lines that became modern insects.  However, our neuro chemicals remain about the same as theirs.  Fortunately, most plant neurotoxins don’t kill us.  We have evolved to eat plants, and we are much larger than insects, so low doses are not fatal.  But drugs can hijack our motivation mechanisms and take control of our lives.

Pg. 245:  Schizophrenia, autism, and bipolar disorder are very different diseases.  Schizophrenia is a cognitive collapse in which every event is imbued with excess personal meaning and the inability to separate inner life from outer life gives rise to hallucinations and delusions.  Autism is manifested in early childhood by a lack of social connectedness and solitary preoccupation with repeated motions and nonsocial thinking.  Bipolar disorder is the product of a broken mood state that causes alternating periods of depression and mania.

Despite their differences, these diseases have overlapping features that make an evolutionary perspective especially useful.  Each afflicts approximately 1 percent of populations worldwide.  Each has milder forms that affect 2 to 5 percent of people.  Vulnerability depends overwhelmingly on what genes a person has, but people with schizophrenia or autism have fewer children than other people.  The evidence for genetic causes is strong.  Genetic variations explain about 70 percent of the risk of bipolar disorder, 80 percent of schizophrenia, and 50 percent of autism. 

Pg. 252:  Boys are many times more vulnerable to autism than girls.  Females are better at social tasks and males are better at systematizing. 

Pg. 263f:  Evolutionary biology is the foundational science for medicine and all studies of behavior.  Bringing it to bear on mental disorders offers a new perspective that will lead to new advances.  The explanations in this book do not provide definitive answers.  Each one requires a full investigation by many scientists.  Human minds carve experience into categories defined by functions.  Chairs are for sitting.  Hammers are for pounding.  Eyes are for seeing.  So it seems natural to ask what schizophrenia is for and how anorexia nervosa is useful.  But disorders don’t have functions.  VDAA (Viewing Diseases As Adaptions) is the most serious error in evolutionary psychiatry.  ADHD was not shaped by selection, but mechanisms that regulate attention were.  Serious depression was not shaped by natural selection, but capacities for normal low and high mood were.