Alexandra Carr
12/15/10
Evolutionary Psychology
Depression:
Could it Really be Useful?
Depression is an epidemic. It is the most common mental disorder and
affects millions of people around the world, and you can be sure that if you were
to ask any one of those people, they would tell you they want to get rid of it.
However, recently the growing field of evolutionary psychology has started to
examine depression through the lens of evolutionary adaptation. Evolutionary
psychologists analyze traits with the theory that each trait is the product of
natural and/or sexual selection, and endures because it is beneficial to posses it.
Therefore, we all have the same evolved set of adaptations that solved problems
that were present in our ancestral environment. Many psychopathologies are not
addressed in evolutionary psychology research because they present
themselves only in a very small percentage of the population, but because
depression affects so many people, it is very likely that it is an evolutionary
advantageous adaptation. Could it really be possible that depression—a
condition that is in fact defined by having a negative impact on life—was once
helpful to us?
Negative Emotions
The fourth edition of The Diagnostic and Statistical Manual of Mental
Disorders (DSM-IV) has a long list of symptoms to define Major Depressive
Disorder. The individual must have periods of depressed mood for at least two
weeks, as well as have at least four other symptoms of depression, which include
fatigue, weight loss or gain, excessive or inappropriate guilt, diminished ability to
think or concentrate, insomnia or hypersomnia, diminished pleasure or interest
(anhedonia), feelings of worthlessness, and recurrent thoughts of dying. 1 Other
related mood disorders are Dysthymia, Bipolar Disorders I and II, and Seasonal
Affective Disorder (SAD). Dysthymia is characterized by a depressed mood for
two or more years, along with other depressive symptoms.2 Bipolar I Disorder is
described as having one or more manic episodes, usually accompanied by Major
Depressive episodes, and Bipolar II entails one or more Major Depressive
episodes and at least one hypomanic episode. 3 SAD, though not specifically
defined in the DSM-IV, is a change in mood with a seasonal pattern, almost
always with people becoming depressed in the wintertime.4 For all these mood
disorders, a key component in diagnosis is that the symptoms must be strong
enough to have a negative impact on your life, whether it is at home, at work, or
in social situations.5 So how could something that has to negatively affect you
have been beneficial?
Firstly, it is important to eradicate the negative connotations of bad
feelings. This is a difficult thing to do; indeed, our language will not even allow us
1
American Psychiatric Association. The Diagnostic and Statistical Maunual of Mental
Disorders, Fourth Edition. 1994.
2
American Psychiatric Association
3
Ibid.
4
The Mayo Clinic. “Seasonal Affective Disorder Definition.” Available at:
http://www.mayoclinic.com/health/seasonal-affective-disorder/DS00195
5
American Psychiatric Association.
to do it, because there are no positive words about bad feelings, and trying to
describe a bad feeling positively just leaves you with a heap of oxymorons. But it
is necessary to recognize that negative emotions have a function. Randolph
Nesse compiled a compelling list in his article ―The Evolution of Hope and
Despair.‖ He argued that despair serves to prevent further immediate losses (if
your baby gets eaten by a lion, grab your kids and run away from the lion), to
avoid situations that caused the loss (stay away from that lion in the future), to
warn kin in order to prevent them from experiencing the same loss (that way,
your sister’s baby will not get eaten by a lion and your genes will live on), to get
help from kin (your sister sees that you are sad so she brings over a dead
opossum for dinner), to recover the lost object (searching seems futile today, but
in ancestral times if your baby simply wandered into the bush, there would be a
good chance he was just lost and needed help getting home), and to replace the
lost object (have another baby soon, so your genes will carry on).6 More
abstractly, despair makes you ruminate, which makes you understand the cause
and meaning of the loss, as well as how to avoid it in the future; reassess your
life and debate whether a change in life strategy is necessary; and offer
reparations or punish yourself in attempt to reconcile a lost relationship if, for
example, your mate left you because of your infidelity.7 Also, if it is a loss in
status, despair would make you retreat, thus avoiding further attacks.8
6
Nesse, Randolph M. “The Evolution of Hope and Despair.” Social Research,
0037783X, Summer99, Vol. 66, Issue 2.
7
Nesse, Randolph M.
8
Ibid.
Another important function of depression and despair is to tell you when to
quit. We tend to think of quitting as bad and perseverance as good, but in reality,
sometimes persisting in efforts in vain is more detrimental. If the effort is futile,
there is no point in wasting time, energy, and resources on it. Throwing in the
towel is an important ability to posses, so you can dedicate yourself to something
that will actually pay off.
So negative emotions do have beneficial and adaptive values. But then
why would we have a mechanism that draws them out to the point of debilitation
and lifelong misery? There are a few different theories.
Resource Gain
One theory is that depression is a plea for help, and a way of manipulating
kin into providing resources for you.9 This is frequently associated with post-
partum depression, which makes a good deal of sense. Immediately after and
throughout the months following birth, not only is a mother physically weakened,
but she now has to take care of a completely dependent infant. This effort is not
only draining, but also prevents her from gathering sustenance and working for
her livelihood. Furthermore, she now has to provide for another individual, so
she has more work to do and less time, energy, and ability to do it. The flaw in
this theory, however, is that reaction to depressed people is largely negative. 10
9
Lewis AJ. Melancholia: a clinical survey of depressive states. J Mental Sci. 1934;80:1-
43. And Hagen EH. The functions of postpartum depression. Evolution Hum Behav. In
press.
10
Coyne JC, Kessler RC, Tal M, Turnbull J. “Living with a depressed person.” Journal of
Consultative Clinical Psychology. 1987;55:347-352. 29.
So while depression may incite pity in others, they are not likely to respond
positively by bringing help and resources.
Energy Conservation
Another theory explaining depression is that it is a way to withdraw and
conserve resources. This is frequently associated with SAD, and it is logical that
what manifests itself as lethargy, anhedonia, and hypersomnia in the winter
would have once been very effective at keeping us close to the fire and
conserving energy when there was not an abundant amount to expend.
Furthermore, in addition to normal depressive symptoms like fatigue and
hypersomnia, SAD has more specific features such as increased appetite and
carbohydrate cravings.11 Unfortunately, extremes of this kind of withdrawal
behavior do not work in the long run. Eventually you need to find the motivation
and energy to get up and search for sustenance, or you will perish. It is also
damaging to social relationships; as mentioned above, people do not respond
well to depressed individuals.
Adaptation to Circumstance
Returning to the idea that depression helps you know when to quit, some
believe that its main function is a way to adapt and accept that a goal is
unattainable. In a study of adolescent girls, Wrosch and Miller found that higher
11
Rosenthal, N. E., Sack, D. A., Gillin, J. C., Lewy, A. J., Goodwin, J. C., Davenport, P.
S., et al. (1984). Seasonal affective disorder: A description of the syndrome and
preliminary findings with light therapy. Archives of General Psychiatry, 41, 72–80. And
Young, M. A. (1991). The temporal onset of individual symptoms in winter depression:
Differentiating underlying mechanisms. Journal of Affective Disorders, 22, 191–197.
baseline depressive symptoms increased the ability to disengage from an
unachievable goal.12 Abandoning an impossible goal is a positive thing because
it promotes quality of life, enables you to engage yourself in more fruitful
activities, and most importantly, decreases depressive symptoms.13
On the opposite side of the spectrum, some believe that depression is a
way to prevent us from giving up. Certain situations, like those in which you have
made a significant lifetime investment, should not necessarily be abandoned.
For example, if you have spent your entire life training and educating yourself for
a particular career or courting a single person, it would be foolish to just throw
those investments away, so depression serves to keep you in place. The
problem with this mechanism is that it does not translate properly into modern
society. In ancestral times, people would have multiple long-term mates in their
lifetimes, and did not commit themselves to a lifelong career in one area; they
simply worked, hunted, or gathered as needed. Now, however, we place a high
value in lifelong commitments that are difficult or even impossible to walk away
from, which makes us feel hopeless, trapped, and depressed.14 Thus, a
mechanism that was once meant to make us stay with a mate just a little bit
longer until our offspring was more competent backfires and drags itself out into
major depression.15 It also further perpetuates itself by getting stuck in a positive
12
Wrosch, C., & Miller, G. E. (2009). Depressive symptoms can be useful: Self-
regulatory and emotional benefits of dysphoric mood in adolescence. Journal of
Personality and Social Psychology, 96(6), 1181-1190.
13
Wrosch, C. and Miller, G. E.
14
Nesse, Randolph M. “Is Depression an Adaptation?” Arch Gen Psychiatry, Volume
57, January 2000. Available from www.archgenpsychiatry.com
15
Nesse, Randolph M.
feedback loop: depression keeps you from walking away from something, but
that failure to disengage makes you more depressed.16 This would be an
example similar to anxiety; it is a useful trait but too much of it creates a problem.
Trait Trade-off
A common reason for seemingly maladaptive traits it that they are
somehow associated with a positive adaptation. An example is the male
peacock’s tail: it makes the peacock more visible to predators, makes it more
difficult to escape those predators, and takes energy to create and maintain, but
it improves the peacock’s chances of mating by signaling fitness to females. It
has been long noted that creative people are more likely to suffer from mood
disorders, so there is a correlation between depression and creativity. 17 This
point is often brought up in the evolutionary rationalization of Bipolar Disorder.
Many think that the major depressive episodes suffered by Bipolar individuals are
a trade off for the high energy, creativity, and productivity experienced during
manic episodes.18 While this could be true in part, it is worthwhile to highlight
that manic episodes are also characterized by reckless, irresponsible, self-
destructive behavior, psychosis, and substance abuse. It is possible (and more
likely, as reflected by its small representation in the population) that Bipolar
disorder really is just a disease, and it has been perpetuated by risky,
promiscuous sex during manic episodes.
16
Nesse, Randolph M.
17
Gaulin, S. and McBurney, D. Evolutionary Psychology, 2nd ed. Prentice Hall: 2003.
18
Gaulin, S. and McBurney, D.
Social Rumination
Human beings are highly social animals. We thrive on contact with fellow
humans, seek their love and approval, and create vast, complex social
structures. That social structure takes huge amounts of energy to conceive,
maintain, and navigate, and living among other people requires social tactics to
keep up relationships, get what you want from them, and anticipate what they
could do for or against you. The mental faculties necessary for these actions
require a lot of energy. Watson and Andrews propose that depression is a way
to reserve the energy necessary to work out these social problems. They say
that the lethargy and anhedonia symptomatic of depression are ways of
preventing us from using the energy that should be directed towards solving an
important social problem.19 This can be expanded to any number of problems,
like how to pull yourself out of unemployment.
This can also be tied in with hypersomnia and the nature of dreaming,
which is our brain’s way of unconsciously ruminating and solving problems.
During sleep cycles, there are two distinct stages: rapid eye movement (REM)
sleep and non-REM sleep.20 We dream during both stages, but the dreams are
very different. During non-REM our dreams are more practical; we practice
skills we used during the day and review the events that are relevant to us at the
19
Watson, Paul and Andrews, Paul. “Toward a revised evolutionary adaptationist
analysis of depression: the social navigation hypothesis.” Journal of Affective Disorders
Volume 72, Issue 1, October 2002, Pages 1-14.
20
“What are Dreams?; Nova.” Directed by Charles Colville and Sara Holt. PBS, 2009.
moment.21 REM dreams are more fantastical, and serve as a way for us to
safely try out different scenarios and see what would happen if we did certain
things.22 Thus, REM sleep is our ruminating sleep, and depressed people not
only sleep more but have longer periods of REM sleep than non-depressed
people.23 There is no way to tell which causes the other, but it is possible that
depressed people sleep more so they can ruminate safely.
Social Yielding
Another theory has to do with conflict. It suggests that depression after
defeat in a conflict resulting in loss of social status serves to make the loser stop
competing with the winner, preventing further injury or loss in social status;
accept that he has indeed lost; and signal submission, which would make the
winner cease oppressive behavior.24 This approach is logical, but as it
specifically concerns conflict and loss of rank, it has limited application.
In Conclusion…
Obviously there are many theories about the purpose of depression, and
beyond those, there are still many more people who simply think it is a disease.
This is easy to believe; the kneejerk reaction when thinking about depression
evolutionarily is that the ancestors who slept constantly and did not put energy
into finding food or mating would have died off pretty quickly. Surely, it becomes
a pathology in its extremes and when persists a long period of time, but it seems
21
“What are Dreams?: Nova.”
22
“What are Dreams?: Nova.”
23
Ibid.
24
Price et al., 1994. J.S. Price, L. Sloman, R. Gardner, P. Gilbert and P. Rohde , The
social competition hypothesis of depression. Br. J. Psychiatry 164 (1994), pp. 309–315.
unlikely that something so common is just a disease. Each of these models has
a specific application and specific flaws, but they can all work in conjunction.
Also, there is evidence that different adverse situations result in different and
appropriate depressive symptom patterns.25 It seems most likely that all of these
models are valid in certain circumstances, and there are surely even more out
there. In the end, it is crucial to remember that something that feels bad could
be—(and probably is, or did at one point—doing something good for us.
25
Keller, M. C., & Nesse, R. M. (2006). The evolutionary significance of depressive
symptoms: Different adverse situations lead to different depressive symptom patterns.
Journal of Personality and Social Psychology, 91(2), 316-330.
Bibliography
American Psychiatric Association. The Diagnostic and Statistical Maunual of
Mental Disorders, Fourth Edition. 1994.
Coyne JC, Kessler RC, Tal M, Turnbull J. ―Living with a depressed person.‖
Journal of Consultative Clinical Psychology. 1987;55:347-352. 29.
Gaulin, S. and McBurney, D. Evolutionary Psychology, 2nd ed. Prentice Hall:
2003.
Keller, M. C., & Nesse, R. M. (2006). The evolutionary significance of depressive
symptoms: Different adverse situations lead to different depressive
symptom patterns. Journal of Personality and Social Psychology,
91(2), 316-330.
Lewis AJ. Melancholia: a clinical survey of depressive states. J Mental Sci.
1934;80:1-43.
The Mayo Clinic. ―Seasonal Affective Disorder Definition.‖ Available at:
http://www.mayoclinic.com/health/seasonal-affective-disorder/DS00195
Nesse, Randolph M. ―The Evolution of Hope and Despair.‖ Social Research,
0037783X, Summer99, Vol. 66, Issue 2.
Nesse, Randolph M. ―Is Depression an Adaptation?‖ Arch Gen Psychiatry,
Volume 57, January 2000. Available from www.archgenpsychiatry.com
Price et al., 1994. J.S. Price, L. Sloman, R. Gardner, P. Gilbert and P. Rohde ,
The social competition hypothesis of depression. Br. J. Psychiatry 164
(1994), pp. 309–315.
Rosenthal, N. E., Sack, D. A., Gillin, J. C., Lewy, A. J., Goodwin, J. C.,
Davenport, P. S., et al. (1984). Seasonal affective disorder: A description
of the syndrome and preliminary findings with light therapy. Archives of
General Psychiatry, 41, 72–80.
Watson, Paul and Andrews, Paul. ―Toward a revised evolutionary adaptationist
analysis of depression: the social navigation hypothesis.‖ Journal of
Affective Disorders, Volume 72, Issue 1, October 2002, Pages 1-14.
―What are Dreams?; Nova.‖ Directed by Charles Colville and Sara Holt. PBS,
2009.
Wrosch, C., & Miller, G. E. (2009). Depressive symptoms can be useful: Self-
regulatory and emotional benefits of dysphoric mood in adolescence.
Journal of Personality and Social Psychology, 96(6), 1181-1190.
Young, M. A. (1991). The temporal onset of individual symptoms in winter
depression: Differentiating underlying mechanisms. Journal of Affective
Disorders, 22, 191–197.