The Evolutionary Significance Of Affective Temperaments
Hagop S. Akiskal, MD
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An evolutionary perspective is not part of the thinking
repertoire of a psychiatrist when faced with a mentally ill
patient. Nonetheless, such an approach has been developing on
the sidelines of psychiatry with potentially very important
contributions to understanding why mental disorders exist.
Unfortunately, while promising, Darwinian psychiatry is fraught
with methodologic difficulties. Unlike the record of somatically
transmitted traits, there is virtually nothing about the
behavior of our species before prehistoric times to serve as
objective data on which to build rational evolutionary
explanations. Although a great deal can be gleaned from the
behavior of other animals, a field which is known as ethology,
mental disorders are far more complex than the behavior of
subhuman primates and mammals.
For this reason, I believe that the "end of the
beginning" of the Darwinian perspective on
mental disorders should attempt ingenious methods of validation.
This report attempts to sketch out a theoretical perspective and
some data-based attempts to validate it.
A Theoretical Framework
Bipolar disorders, like anxiety disorders, represent
excellent opportunities to conceptualize the link between mental
disorders and temperamental attributes. Temperament refers to
stable behavior traits with strong affective coloring. Current
evidence suggests that bipolarity lies along a continuum from
extreme temperament to full-blown affective illness.
Less work has been conducted on the continuum between normal and
extreme temperaments, but whatever data are
available do suggest that most temperamental traits are
continuously distributed. Although the link between temperament
and mental disorder goes back to the earliest days of
psychological medicine in the Greek period, it is not presently
part of the orthodox body of psychological and psychiatric
Nonetheless, many authorities have hypothesized a continuum
between cyclothymia and full-blown manic-depressive illness. The
German psychiatrist Kretschmer expressed it most
eloquently when he stated that "endogenous psychoses are
nothing but exaggerated forms of normal temperament." The
British psychiatrist Miller put it more tersely:
"The term manic-depressive psychosis may be correct enough
for use in mental hospitals...the term cyclothymia, on the other
hand...includes all the milder manifestations, and brings the
whole syndrome within the frontiers of everyday life."
Within this theoretical framework, the author submits that
affective temperaments play a fundamental role in the
predisposition to affective disorder and affective psychoses.
Those who oppose this view question why "normal" or
"supernormal" traits should underlie a major mental
aberration. The question could be more meaningfully examined
from the reverse position. I would suggest that the affective
temperaments represent the most prevalent phenotypic expression
of the genes underlying bipolar disorder: the disorder itself is
an aberration and exists simply because the genes
themselves, likely to conform to oligogenic models, are useful
for evolutionary ends and, in principle, should be demonstrable
in other species. If this model is correct, then adaptive traits
must be more common among the "dilute" forms of the
illness (ie, bipolar II vs bipolar I), or among the biological
"clinically well" relatives who carry some but not all
of the genes of the mentally ill proband. Indeed, in a study
conducted in collaboration with Kareen Akiskal, we
found that creativity was present in 8% of bipolar II or III vs
a negligable rate in bipolar I, schizoaffective, and unipolar
depressive patients; the cyclothymic temperament appeared to
mediate such creativity. Also, Coryell and colleagues
and Richards and colleagues demonstrated far
greater achievement in the families as opposed to the identified
An ethological hypothesis can therefore be formulated that
would suggest that anxious worrying temperamentally subserves an
altruistic role and that a phobic temperament in
fostering dependence would favor the marital bond,
the depressive or melancholic temperament promotes a work
orientation, cyclothymic temperament is involved
in exploration and creativity, and the
hyperthymic temperament in territoriality and leadership.
The Hyperthymic Temperament
An ethological hypothesis can be supported in the most
straightforward fashion with the hyperthymic temperament. This
temperament is characterized by exuberant, upbeat, overenergetic,
and overconfident lifelong traits. Obviously,
such traits have great relevance to territoriality and
leadership. Other authors have also described this trait
behavioral pattern. For instance, Possl and von Zerssen
describe the biography of these individuals in the following
traits: (1) vivid, active, extroverted; (2) verbally aggressive,
self assured; (3) strong-willed; (4) self-employed; (5)
risk-taking and sensation-seeking; (6) breaking social norms;
and (7) generous and spendthrift. This contribution came from a
study of the premorbid behavior of bipolar patients. Gardner,
based on a more intuitive formulation, described the behavior of
these individuals in even more territorial terms: (1)
cheerfulness and joking; (2) irrepressible infectious quality;
(3) unusual warmth; (4) expansive; (5) increased self
confidence; (6) scheming; (7) robust and tireless; and (8) pushy
We have developed an operational definition of this
temperament and studied in a self-rated form (21 items). In a
paper in press, we have reported emergence of a
distinct hyperthymic factor from our analysis of 110 items
representing 5 different temperaments. It is noteworthy that
aspects most relevant to territoriality and leadership had the
highest loadings on this factor, including "I am the kind
of person who likes to be the boss" (Table 1).
Table 1. The Hyperthymic Factor
|51. I have a gift for speech, convincing and
inspiring the others
|48. I often get many great ideas
|52. I love to tackle new projects, even if risky
|45. I like telling jokes, people tell me I'm
|58. I have abilities and expertise in many fields
|54. I am totally comfortable even with people I
|55. I love to be with a lot of people
|60. I am the kind of person who likes to be the boss
The Generalized Anxious Temperament
We have also hypothesized an evolutionary role for a
generalized anxious temperament that represents
an exaggerated personality disposition toward worrying. It can
be considered an "altruistic anxiety" subserving,
hypothetically, the survival of one's extended phenotype in a
keen selection paradigm. That worrying would increase upon
relaxation is not a paradox, and makes sense in an ethological
perspective. It is of great theoretical and practical relevance
in our analysis of the 26 traits that constitute
this construct in its self-rated form (among the total of 110
temperament traits) that an independent generalized anxious
factor emerged with strong loading on the 3 items related to
worrying about one's kin (Table 2).
Table 2. The Generalized Anxious Factor
|99. I am often fearful of someone in my family
coming down with a serious disease
|100. I'm always thinking someone might break bad
news to me about a family member
|98. When someone is late coming home, I fear they
may have had an accident
The Cyclothymic Temperament
Since our original study going back to 1977,
we have found that "falling in and out of love" was a
major characteristic of these individuals. This is obviously of
great ethological significance, because ultimately Darwinian
evolution works through sexual behavior in transmitting
desirable traits. We have hypothesized that the flamboyant and
restless pursuit of romantic opportunities in cyclothymia
subserves such a mechanism. Their creative bent
in poetry, music, painting, or fashion design, too, may have
evolved to subserve such a primordial sexual function.
Further Evidence for the Evolutionary Function of
Depressive traits, among other functions, would subserve
sensitivity to the suffering of other members of the species,
while generalized anxiety temperamentally would subserve
altruistic worries; it would not be far fetched to suggest that
such traits would enhance kin survival and, by proxy, one's own
genome. Cyclothymic traits, with their capriciousness, would
make the subject more difficult to attain for lovemaking,
thereby assuring that the most robust spouse could be found, who
would assure better survival of offspring emerging from such
unions. As already stated, hyperthymic traits would lend
distinct advantages in exploration, territory, leadership, and
mating. These are just some of the possibilities of the rich and
complex temperamental traits within an evolutionary framework.
In line with this formulation, new data from
the author's research (Table 3) have shown that both cyclothymic
(.35) and hyperthymic (.34) traits are positively and the
depressive (-.10) and anxious (-.14) negatively correlated with
TCI's novelty seeking. By contrast, harm avoidance is positively
correlated with the depressive (.58) and the anxious (.48) --
but interestingly also with the cyclothymic (.49) -- and
negatively with the hyperthymic (-.53).The data support the
proposed evolutionary functions of the affective temperaments.
Table 3. Correlation Coefficients Between Temperaments and
Dys, dysthymic; Cyc, cyclothymic; Hyp, hyperthymic; Irr,
irritable; Anx, generalized anxious
These data have important implications for the treatment of
mood disorders, particularly the treatment of bipolar disorders.
Because dilute expressions of the illness may persist between
major episodes, aggressive treatment with mood stabilizers can
comprise adaptive functioning and what is unique to the patient
as a person. Except in the acute phases of the illness, the
emphasis in treatment should be more on functioning than
complete mood stabilization.
There are also psychotherapeutic implications.
Generalized anxious temperament can benefit from meditation, a
phobic temperament from cognitive behavioral approaches, a
dysthymic individual from work as therapy, and the cyclothymic
would require rhythmotherapy and limit setting. Hyperthymic
individuals are action rather than psychologically oriented, and
typically shun psychotherapists and psychiatrists. They are more
interested in running the world than "being lectured
to" about the desirability of some behavior change at a
time of major conflict. The approach to such individuals in
psychotherapy is among the most challenging for our field.
- Akiskal HS. Evolutionary psychiatry: the end of the
beginning. Program and abstracts of the American Psychiatric
Association 156th Annual Meeting; May 17-22, 2003; San
Francisco, California. Abstract S52D.
- Akiskal HS. The bipolar spectrum -- the shaping of a new
paradigm. Curr Psychiatry Rep. 2002;4:1-3. Abstract
- Akiskal HS, Placidi GF, Signoretta S, et al. TEMPS-I:
delineating the most discriminant traits of cyclothymic,
depressive, irritable and hyperthymic temperaments in a
nonpatient population. J Affect Disord. 1998;51:7-19. Abstract
- Kretschmer E. Physique and Character. London: Kegan, Paul,
Trench, Trubner and Co. Ltd.; 1936.
- Miller, Royal Soc Medicine, 1930.
- Akiskal HS. From dysthymia to the bipolar spectrum:
bridging practice and research (Jean Delay Prize paper).
Program and abstracts of the XII World Congress of
Psychiatry; August 24-29, 2002; Yokohama, Japan.
- Akiskal HS, Akiskal K. Re-assessing the prevalence of
bipolar disorders: clinical significance and artistic
creativity. Psychiatrie et Psychobiologie. 1988;3:29s-36s.
- Coryell W, Endicott J, Keller M. Bipolar affective
disorder and high achievement: a familial association. Am J
Psychiatry. 1989;146:983-988. Abstract
- Richards R, Kinney DK, Lunde I, Benet M, Merzel AP.
Creativity in manic-depressives, cyclothymes, their normal
relatives, and control subjects. J Abnorm Psychol.
- Akiskal HS. Toward a definition of generalized anxiety
disorder as an anxious temperament type. Acta Psychiatr
Scand. 1998;98(suppl 393):66-73.
- Akiskal HS. Proposal for a depressive personality
(temperament). In: Tyrer P, Stein G, eds. Personality
Disorders Reviewed. London: Gaskell, Royal College of
- Akiskal HS, Rosenthal RH, Rosenthal TL, Kashgarian M,
Khani MK, Puzantian VR. Differentiation of primary affective
illness from situational, symptomatic, and secondary
depressions. Arch Gen Psychiatry. 1979;36:635-643. Abstract
- Akiskal HS. Dysthymia, cyclothymia and related chronic
subthreshold mood disorders. In: Gelder M, Lopez-Ibor J,
Andreasen N, eds. New Oxford Textbook of Psychiatry. London:
Oxford University Press; 2000:736-749.
- Akiskal HS. Delineating irritable-choleric and hyperthymic
temperaments as variants of cyclothymia. J Person Disord.
- Possl J, von Zerssen D. A case history analysis of the
'manic type' and the 'melancholic type' of premorbid
personality in affectively ill patients. Eur Arch Psychiatry
Neurol Sci. 1990;23:347-355.
- Gardner R Jr. Mechanisms in manic-depressive disorder: an
evolutionary model. Arch Gen Psychiatry. 1982;39:1436-1441. Abstract
- Akiskal HS, Mendlowicz MV, Girardin J-L, et al. Validation
of a scale designed to measure variations in temperament. J
Affect Disord. 2003; In press.
- Akiskal HS, Djenderedjian AH, Rosenthal RH, Khani MK.
Cyclothymic disorder: validating criteria for inclusion in
the bipolar affective group. Am J Psychiatry.
- Akiskal HS. Psychopharmacologic and psychotherapeutic
strategies in intermittent and chronic affective conditions.
In: Montgomery S, Rouillon P, eds. Long-Term Treatment of
Depression. London: J. Wiley & Sons; 1992:245-263.