Darwin and the DSM by James Brody, February 12, 1999

Diagnosis and Evolutionary Theory1

James Brody, Ph.D.2

January 21, 1999

Reminders of Our Past

First, it was noticed recently that some of our female ancestors in Africa had smaller leg bones and a different ankle structure than the males, suggesting to modern scientists that women came to ground from the trees long after the males did. Observers next watched American children on playgrounds; surprisingly, the girls at age 6 climb higher on monkey bars than boys of the same age. Finally, giving young children in Israel or the United States a simulated escape game revealed that girls more often than boys choose to climb trees and climb further out on the branches in order to get away from predators. Israeli girls also climbed higher on the simulated Acacia tree after a coincidental but real terrorist attack.

This sequence of studies -- reported by Richard Coss (rgcoss@ucdavis.edu) at the Human Behavior and Evolution Society in July 1998 -- reveals not only one aspect of our mental architecture but also one of the tactics found in evolutionary research. It's simple to make up stories of how we came to do one thing or another; confirmation requires a series of other steps that can be tedious, lengthy, and laced with possible errors. Despite the risks, evolutionists look for commonalities in response patterns that occur regardless of the human culture that is being studies. Behavior sequences are analyzed for their adaptive design -- that is, what survival problems are solved and how do behavior sequences fit both with each other and with our physical structures. Finally, we try to make specific predictions about data that might be found in modern people, comparing them in different countries and of different races, and relating these new findings both to the environment of a particular era and to our other physical and psychological adaptations.

Another example -- every human 6 year old has a naive biology, a naive physics, and a naive psychology. The last includes notions of how another person thinks and the capacity to interpret the feelings of a second person from facial and vocal displays. Each child tracks others' conduct, monitors social exchanges, and has a sense of fairness and cheating. It seems very probable that chimpanzees, gorillas, and orangutans have the same capacities even if less Simonized.

Carl Sagan and Ann Druyan would perhaps have referred to these traits -- whether tree climbing, the gymnastic talent of young girls, or the untaught capacity for empathy -- as "shadows of forgotten ancestors." Genetics, sociobiology, anthropology, evolutionary psychology, and paleontology offer structures and explanations for how those shadows came to be. These several disciplines also allow predictions about previously unnoticed details of our behavior. It seems plausible that understanding other shadows -- those of emotional distress -- could also be helped by consideration of our probable evolutionary history.

The DSM: An Insect Display Case

Naturalists put things -- shells, insects or pieces of yellowed bone -- in compartmented boxes. Arrays of specimens form on the basis of systematic differences in size, color, and shape, arrays that match the classifier's mind as well as the relationships that he imagines.

Psychiatric diagnoses -- roughly 400 of them -- temporarily occupy a useful display case, the Diagnostic and Statistical Manual, 4th Edition. Intensity and duration are our classification standards for worry, fear, sadness, and grief. Empirical studies of the "natural occurrence" of various disorders show us relationships between some of them. However, because of the self-selected nature of the data and peculiarities of our own evolved mental apparatus, classification and explanation may sometimes be misleading.

Classification by Medicines

Some disorders are more recently classified according to the tools used for treatment -- not such a bad refinement. For example, the '50s and '60s hosted the use of imipramine and lithium and diagnosis according to prescription was popularized. Practitioners commented about a "manic process" if lithium abated a patient's distress; likewise for "schizophrenic process" if chlorpromazine settled them down.

Peter Kramer then gave us "cosmetic psychopharmacology" in the '90s, an understanding that a continuum of discomfort exists for all of us and that many subclinical annoyances respond postively to changes in serotonin. He also suggested that we "listen to Prozac" in order to learn about serotonin and, indirectly, about normal functioning and about psychopathology. Thus, Peter taught us to study the hammer and nail -- Prozac and serotonin -- in order to understand the roof (psychopathology). We now have "serotonergic spectrum disorders" that link such events as self esteem, obsessive compulsive disorder, and panic attacks.

Kramer was right but there are further steps. Serotonin has been in living creatures for about a billion years and does a lot of things. Dopamine and norepinephrine may be equally ancient. Thus, modern information about serotonin reminds us to study not just what it does for us but also for our ancestral relatives and for other species. Prozac opened a door to our past.

A Diagnostic Foundation from Evolutionary Theory

There are several goals that might be achieved from keeping an eye on our ancestors' life styles. Evolutionary understandings should help us to generate diagnostic arrays on the basis of the survival functions for both annoyances such as anxiety, depression, and paranoia but also the zest of elation, grandiosity, and silliness. We also should have a system for diagnoses that incorporates "traits" rather than "disorders" and describes the original functions of our assorted discomforts. An evolutionary system ought to meet the traditional obligations of diagnosis by giving an etiology (both phylo- and ontogenetic), a description of present complaints, suggestions for giving assistance, and a prediction of outcomes. An evolutionary diagnostic system should also:

Understanding Natural Selection

There are several points.

Aspects of Diagnosis and Treatment

Moving from Our Past to Our Future

Finally, Russ Barkley elaborated an earlier theory of Jacob Bronowski, that "executive functions" -- working memory, development of language for memories and exchange of information, sharing of plans, using emotions strategically, and our ability to analyze situations and imagine novel sequences of events -- are perhaps our finest gift from the past 200,000 years. Our executive functions allow us to compare ongoing situations with past experiences and to recall the outcome of our prior behavior. We can choose, on the basis of delayed outcomes, between repeating an earlier sequence of behavior or designing a new one in our minds and implementing it by ourselves or in cooperation with other people. Defects in executive functions commonly lead to the endless repetition of errors, to a failure to plan or to consider options and to depend on emotion and stereotyped responses despite the past ineffectiveness of those same strategies. (We might appraise executive functions more overtly when we see clients instead of making "global assessment of functioning.")

Likewise for us as a species, ignorance of our past guarantees our repeating it. Failure to know about our evolutionary history and the genetic mechanisms that were evolved means that we will react blindly, impulsively, and perhaps disastrously. Certainly, we might have "flown blind" for the past 15 million years or more but have done well because of the survival strategies hammered into our biological executive functions that take the form of genes. However, we now enter times of rapid climate variability and significantly eroded resources. Evolution becomes relevant and not just for knowing our origins but also for using our origins to gain a sense of our possible futures. By knowing where we have been, we can appreciate where we might go. We might still make some choices with the newer parts of our minds instead of relying exclusively on more stubborn, primitive systems that have gotten us to this point.

1.) Dylan Evans, Ph.D. candidate at the London School of Economics and a student of Helena Cronin's, presented a seminar on Evolutionary Psychology and the DSM at last summer's Cape Cod Institute, Healing the Moral Animal: Lessons from Evolution. This year's course is Clinical Sociobiology: Darwinian Feelings and Values and runs from July 19-23, 1999.

2) 1262 West Bridge St, Spring City, PA 19475. (610) 948-5344. Jbrody@compuserve.com. See related work at http:///cgi-bin/ls2.cgi?config=evolutionary/ or http://www.clinical-sociobiology.com. Also submitted to Across Species Comparisons and Psychopathology

Readings

Barkley, R. A. ADHD and the Nature of Self Control. Guilford, 1997

Buss, D. Evolutionary Psychology. Allyn & Bacon, 1999.

Duncan, R. Grooming, Gossip, and the Evolution of Language. Harvard, 1996

Ridley, Matt. Origins of Virtue. Penguin, 1996

Sagan, C. & Druyan, A. Shadows of Forgotten Ancestors. Random House 1992

Stewart, I. Life's Other Secret: The New Mathematics of the Living World. Wiley, 1998

Wilson, E. O. Consilience. NY: Knopf, 1998

Wrangham, R. Demonic Males. 1996

Editor's Note: You are invited to join Jim Brody in discussion of this topic in the Evolutionary Psychology forum.

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