Handbook of Psychology

Diathesis 175

or lifetime history of major depressive disorder between pa-
tient populations with FM and those with RA (Ahles, Khan,
Yunus, Spiegel, & Masi, 1991). Thus, there is accumulating
evidence that depression may be an inherent part of FM and
other pain disorders of unknown origin.

Positive Affect

It is important to keep in mind that depressionis a term that
stands for a heterogeneous set of disturbances of affect and
cognition. Under its umbrella may be found the workings of
two major affect systems: a positive one, characterized by
active, approach behaviors, optimistic expectancies, and
positive emotions, and a negative one, characterized by high
levels of avoidance and retreat behaviors, highly pessimistic
expectancies, and considerable negative emotion. Although
these systems typically operate independently of one another,
they both contribute to our understanding of depression. Both
loss of the capacity for pleasure and sustained elevations in
feeling downhearted and •blueŽ de“ne depressive disorders.
Both of these affect systems may in”uence and are in”uenced
by the chronic pain and disability of musculoskeletal condi-
tions in distinct ways. In an examination of data from three
large community studies of RA patients, Zautra, Burleson,
Smith, et al. (1995) found that these two affect systems were
differentially associated with RA symptoms. RA pain was
strongly associated with higher levels of negative affect, but
was not associated with less positive affect. Disability, how-
ever, was most strongly associated with low levels of positive
affect, and not high levels of negative affect. These two
affects also appeared to be linked with different forms of
coping. Those RA patients who coped actively with the chal-
lenges of their illness were more likely to show high levels of
positive affect. Those who used avoidant and other more pas-
sive strategies tended to experience more negative affect.
How depression plays a role in RA then is best understood by
asking two questions: Does the person experience a relative
de“cit in the positive af fective system and/or an abnormally
high level of negative affectivity?
These distinctions may also be useful in specifying the af-
fective conditions underlying the different forms of chronic
pain. Zautra, Hamilton, and Burke (1999) have provided evi-
dence to suggest that when pain levels are controlled, FM
patients do not differ in level of negative affective responses
from RA and OA patient groups. However, they do appear to
evidence greater de“cits in positive af fects than either RA or
OA groups. During stressful times, these affective conditions
may be particularly important. Zautra, Hamilton, and Yocum
(2000) provide evidence that improvement in positive affect
can reduce disease activity among patients with RA, and

Zautra and Smith (2001) provide further evidence that posi-

tive events may diminish stress-reactive disease processes for

RA patients. Further, Davis, Zautra, and Reich (2001) have

shown that the absence of positive affect is associated with

greater increases in FM pain following the administration of

a laboratory stressor. OA patients did not show the same pat-

terns as the FM subjects, suggesting that affective conditions

are associated with illness symptoms in different ways for

OA and FM patients. Thus, positive affect may serve as a

source of resilience to the effects of stress.

Somatization

Besides depression, chronic pain patients have also been doc-

umented to experience many symptoms of somatization

(Bacon et al., 1994). Somatization is characterized by exces-

sive preoccupation with somatic symptoms and health care

seeking for symptoms with no known cause (American Psy-

chiatric Association, 1994). Somatization disorder has been

associated with chronic pain in general (Wilson, Dworkin,

Whitney, & LeResche, 1994). For instance, somatization be-

havior has been demonstrated in diverse chronic pain condi-

tions such as low back pain (Bacon et al., 1994) and irritable

bowel syndrome (Chang, Mayer, Johnson, Fitzgerald, &

Naliboff, 2000). Thus, it appears that there is only weak evi-

dence of comorbid somatization disorder in musculoskeletal

conditions, and only in FM patients (Kirmayer, Robbins, &

Kapusta, 1988; Wolfe & Hawley, 1999). However, one major

limitation to distinguishing FM symptoms from somatization

behavior is that they share one de“ning feature: widespread

bodily symptoms with no clear physical evidence of a patho-

logical problem.

Social Diathesis Factors

Our discussion to this point has highlighted the biological

and psychological sources of vulnerability and resilience in

adaptation to musculoskeletal conditions. But life experi-

ences, including pain and other symptoms, occur in a social

context. This has profound implications for adaptation and

quality of life. Two important social factors that in”uence the

functioning of individuals with chronic pain include social

support, a source of resilience, and stigmatization, a source of

vulnerability.

Social Support

Supportive social relationships represent one of the most in-

”uential social factors that sustain physical health (Sarason,

Sarason, & Gurung, 1997). Supportive social relationships