Although depressed persons would at first hardly enjoy viewing
their unpleasant symptoms and behaviors from this angle, the contributors
to this volume hypothesize that not only are mood disorders the
result of situations or lives that go wrong, but they also often
serve important evolutionary purposes. But to understand the adaptive
functions of depression (and its cousin, anxiety) holds out the
promise of more effective treatment strategies.

The titles of the various chapters – – all of which were written
by respected authors – – signal the general themes to come. For
example, consider Varieties of Submissive Behavior as Forms
of Social Defense: Their Evolution and Role in Depression; How
the Involuntary Defeat Strategy Relates to Depression; and
Subordination, Self-Esteem, and Depression.

In the introduction, the editors write, “[I]n any conflict
situation there will often be a winner and a loser, [and] a central
question arises: Which strategies have evolved to enable the one
who is losing to decide when to try harder and when to accept
the inevitability of defeat and adjust one’s behavior accordingly?”
(p. ix). However, they go on to point out, some people may find
a submissive strategy inherently advantageous, and so “Such
submissive behavior need not be associated with a lack of confidence”
(p. x).

In the first chapter, co-editor Gilbert observes that submissive
behaviors developed early in the evolution of various species,
including our own. Such behaviors are even observed in reptiles,
though in social species, especially in mammals, submissive strategies
are much more complex and variable. Further, submissive strategies
are only useful in intra-specie social contexts, since submitting
to a predator would be fatal and therefore (in most cases) detrimental
to the individual and, in extension, to the group as well.

Gilbert inventories ten different submissive strategies that have
been observed in the most social of species. These include escape,
ambivalent defense, arrested flight, arrested fight, loss
of control (avoidance), defeat, enclosed avoidance, reverted escape,
infantilism, and affiliative alliance. Each of these strategies
serves a slightly different purpose and is usually elicited unconsciously
and automatically. Presumably the different types and features
of depression in humans correspond to these strategies.

Interestingly, in this light, submission (and by extension depression)
is not complete loss, and still affords the individual some degree
of control of the situation. “However, control varies greatly
according to the rank of an animal….[and] subordinates are
generally more tense and defensive than dominant animals. They
show reduced explorative behavior and social confidence [and]
have higher levels of stress hormones . . .” (p. 37).

In another chapter, the other co-editor, Sloman, perceptively
notes that “The evolutionary theorist faces the challenge
of having to explain why mood disorders, which are often maladaptive
for the individual, have not been weeded out by natural selection
and, moreover, continue to have a high prevalence” (p. 47).
He goes on to show how the involuntary defeat strategy (IDS, as
he abbreviates it), which was evolved for adaptive purposes, can
become maladaptive for an individual human in today’s world.

When it works properly, IDS limits the level of aggression that
might occur between individuals, signals “no threat”
to opponents and “don’t intervene” to cohorts, and puts
the subordinated person in a “giving up” frame of mind.
The IDS fails to accomplish these goals, however, when the defeated
individual cannot effectively escape the conflict situation. When
this happens, the result is often learned helplessness followed
by chronic, self-reinforcing, and thereby pathological depression.
Depressed people often seem to resort prematurely to an IDS, even
when the conflict is simply imagined or expected. “Premature
triggering of the IDS may be attributed to a history of having
autocratic and punitive parents, physical abuse, or sexual abuse”
(p. 58).

Other chapters delve into the complex biological correlates of
IDS and depression; a proposed intersection of pride and shame;
social comparison processes in depressed individuals; the role
of and risks to self-esteem; and the special usefulness of cognitive
mediation (cognitive-behavioral therapies) with depressed persons.

The ideas presented in this book should be exciting for therapists
and depressed clients alike, because the evolutionary approach
to understanding depression readily suggests the development of
effective psychotherapeutic treatment strategies. Established
and traditional theories are not directly challenged – – but the
addition of the evolutionary perspective would certainly be possible
and would be highly beneficial to them, although some theories
would require a significant bit of adaptation and reformulation.

This book is well worth reading and its content deserves thoughtful
consideration. I have only a couple of suggestions for future
editions.

As much as I enjoyed and benefited from this book, I didn’t find
in it a serious consideration that there might be a biologically
based, natural distribution of mood states in groups of humans.
Any psychotherapist would agree that occasionally the client is
encountered who, although with unremarkable developmental history,
a supportive and loving family, interesting work and a decent
income, still finds him or herself dysphoric, anhedonic, pessimistic,
or generally unhappy with his or her lot in life. (We’ve borrowed
from the French a word for this condition, anomie – – an
inexplicable feeling of alienation from society or from our own
lives, a sense of purposelessness.) In such cases it’s unusually
difficult to hypothesize likely causes, or in some way explain
the unhappiness. It’s as though nature has evolved in human groups
a range of “resting mood states”, just as it has provided
a range of personality types. In a band of hunter-gatherers, it
might have been advantageous to have both optimists (“Let’s
jump on that wooly mammoth right now!”) and pessimists (“That
thing has dangerous tusks and anyway what would we do with so
much meat?”).

In addition, the role of anxiety symptoms in depression received
only a brief glance in this book – – this subject deserves a much
fuller exploration, since a substantial percentage of clients
present not with depressive symptoms but with anxiety; but later,
during the course of treatment, it’s quite common to discover
that the client suffers, after all, from significant depression
as well.

© 2001 Keith Harris

Keith Harris, PhD,
is a clinical psychologist and supervisor of Victor Valley Behavioral
Health Center in San Bernardino county, California. His interests
include clinical supervision, the empirical basis for psychotherapy
research (and its design), human decision-making processes, and
the shaping of human nature by evolutionary forces.

Categories: Genetics, Depression

Tags: Depression (Unipolar)