Summary of:
Glass, D. J. (2012). Evolutionary clinical psychology, broadly construed: Perspectives
on obsessive-compulsive disorder. Journal of Social, Evolutionary, and Cultural
Psychology, 6(3), 292-308.
By Melissa Ortiz, Elaine Matteucci, Katie Bowden, Scott Frazier
For Dr. Mills’ Psyc 515 class, Spring, 2014
Obsessive-compulsive disorder (OCD) is an anxiety disorder that is
characterized by “recurrent, unwanted thoughts (obsessions) and/or repetitive
behaviors (compulsions)” (National Institute of Mental Health). Though there is no
known etiology for OCD, there are some possible treatments. These include cognitive
behavior therapy and medications, which are mostly serotonin-selective reuptake
inhibitors. Researchers have slowly constructed an evolutionary approach to
understanding OCD, since they have realized that the brain is an evolved organ, like
every other organ in our body. Therefore, if we investigate how and why it evolved,
we may understand its current workings.
An evolutionary approach could be greatly beneficial to understanding to any
domain an could defined as “the application of biological evolution to the study of the
mind.” A critique in the evolutionary approach is adaptationism, where traits are
supposed to have evolved for the greater fitness of the organism. This view is
particularly bad in the realm of clinical disorders. Therefore, we need other
explanations for mental illnesses. Luckily, adaptationist perspectives are only a small
subset evolutionary approaches to mental illnesses.
The purpose of this paper is to differentiate evolutionary approaches to mental
disorders from adaptationism, using the example of OCD. Discussion points will
relate to the ultimate (evolutionary) cause.
Adaptationism theories to explaining OCD is that these traits were once
beneficial to our fitness. OCD is often thought of as an overexpression of traits or an
extreme adaptation. However, none of the adaptationism perspectives realize that
OCD may be an adaptation that is working just fine, but just may not be necessarily
beneficial to our environment now.
Abed and de Pauw (1998) claim that our “mental module,” which causes us to
think of possible risk scenarios and how to escape them, allows us to think of a priori
solutions to problems. OCD is an malfunction of this system. However, this model is
seen as incomplete. Others cite that the compulsions of OCD, such as cleaning, may
be been beneficial to foraging (Polimeni, Reis, & Sareen, 2005). These authors also
suggest that OCD groups benefited from OCD individuals and therefore resulted in a
net inclusive fitness for OCD along with pressure to maintain OCD genes at an
optimal frequency.
These theories rely on the balancing of OCD genes, which can be possible by
the heterozygote advantage (individuals who carry two different alleles, which an
advantage over those who are homozygous for a particular gene). Antagonistic
pleiotropy, in which a gene has both advantageous and disadvantageous effects
balance each other out, is another mechanism for balancing genes. This has been
proposed to help explain many mental illnesses.
Another theory, by Keller and Miller (2006), is based on mutation-selection
balance- the fact that mutations can arise in a population “faster than natural
selection’s ability to select against them.” Since every individual inherits a relatively
small number of mutations from their parents, a combination of these genes could
result in certain behaviors that can be classified as a mental illness.
Table 1. Possible Evolutionary Forces Accounting for Existence of Mental Disorders
Adaptation
Trait shaped by natural selection to solve
adaptive problems of ancestral
environments
Mismatch
Once-adaptive traits which can be
maladaptive or distressing in novel
environments
Byproduct
Trait not directly shaped by natural
selection, but which arose as a result of
selection on other traits
Balancing selection
Trait which is harmful in some
circumstances but is maintained by
natural selection because its benefits
offsets its costs in particular environments
Mutations
Mutations in single or multiple loci
results in aberrant functioning; natural
selection may be too weak to select
against many minor mutations and thus
mutations are maintained in gene pool
(mutation- selection balance)
Lesion/environmental insult
Physical damage, environmental stress, or
developmental circumstance results in
aberrant functioning
Evolutionary theorists argue that diagnoses of disorders strictly according to the
DSM are too narrow and limiting in their findings. This is due to the fact the criteria
listed in the DSM only takes theoretical descriptions of the clinical syndromes into
account and lacks an evolutionary approach. Therefore, it lacks additional
consideration of how the mind is designed to function and how this can influence the
diagnosable disorder as a result. In response, researchers constructed various
perspectives/possibilities regarding mental disorders in order to determine whether or
not they are being accurately identified as literal disorders in the brain’s ability to
function.
One evolutionistic possibility proposed for how mental disorders arise is the
environmental mismatch theory. This suggests the possibility that a mental or physical
disorder came about as a result of the individual being exposed to an environment that
was unfamiliar to his/her ancestors. Since his/her ancestors never familiarized with
such an environment he/she is not properly equipped for how to handle all the
unfamiliar stimuli and components of the environment. For example, advocates of this
theory have argued that the modern culture of American society is unnaturally socially
structured and therefore can increase individuals’ likeliness in developing ADHD.
Wakefield’s concept of harmful dysfunction stems off of this concept is
describing how something like ADHD/other “syndromes” would or would not be
classified as a disorder. This concept encompasses the idea that a condition should
only be considered to truly be a disorder if it is both harmful and a dysfunction. The
idea that the condition is harming suggests that it suffices the social values that are
considered important in the judgment of the disorder as well as the effects it seems to
have on the person’s functioning and impairments. The idea that the condition is
dysfunctional relies on scientific analysis of the function. Wakefield’s emphasizes that
both these characteristics must be present in order for the condition to be considered
as a disorder. This concept has been especially enlightening for theorists regarding
OCD. Primarily all have agreed that it would be considered a disorder when related to
these criteria because it is both harmful (in that it’s distressing) and dysfunctional (in
that there seems to be functional dysregulations represented in the brain).
Murphy and Stitch explain these dysregulations occurring in the brain by
describing the brain as an evolved system of inter-linked domain specific computation
modules. In this sense, the perceive disorders like OCD occurring due to faulty
information flow from one module to the other. Since these modules are all
interrelated in terms of input and output, a fault at one location between modules can
disrupt the whole system. In relation to this interpretation, Glass suggests that there
are four dissociable patterns of dysfunction in OCD that are each representative of a
specific part of the mental processing that has been affected. Specifically, these four
symptoms suggest distinct neural pathways involved in each of the affected domains,
which include: washing and cleaning, acquiring physical resources, patterns numbers
symmetry and order, and precautions in avoiding danger.
These evolutionary
theories developed in response to mental disorders demonstrate how evolutionary
thinking is grounded in applications broader than just the implications of adaptations.
While adaptations are an important element to consider, evolutionary theorists
recognize and make use of the influences that also stem from population genetics,
mutation-selection balance, ethology, and phylogenetics. The modern evolutionist
understands and acknowledges that phenotypes are a result of an interaction of
influence from both our genes and the environment and therefore accept taking a
holistic approach to analyzing such components.
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