170 Arthritis and Musculoskeletal Conditions
should devote balanced attention to these dual in”uences.
Thus, in this chapter, we review the biological, psychological,
and social sources of vulnerability and resilience in the most
common forms of arthritis in the United States: rheumatoid
arthritis (RA), osteoarthritis (OA), and “bromyalgia (FM).
DIATHESIS
According to the diathesis-stress model, the process of adap-
tation and its health consequences are dependent on an
individual•s vulnerability and resistance to the threats to psy-
chological and physical well-being posed by stressful cir-
cumstances. There exist individual differences in biological,
psychological, and social sources of vulnerability and re-
silience, which ultimately interact with stress factors to pro-
duce outcomes. Individuals with musculoskeletal conditions
confronted with the stress of chronic pain react differently
according to their relative balance of vulnerability and re-
silience, so that identical stressors do not produce identical
outcomes across individuals. Furthermore, despite the fact
that RA, OA, and FM have many symptoms in common and
are often treated within the same medical specialty, each dis-
order varies in composition of biological, psychological, and
social factors. Thus, there are individual and disease-speci“c
sources of variability in biopsychosocial diathesis factors. In
this section, we describe the biological and epidemiological
features of each disorder and identify psychological and so-
cial sources of vulnerability and resilience to stress.
Biological Diathesis FactorsRheumatoid ArthritisCurrently, more than two million Americans suffer from
either juvenile or adult RA (Lawrence et al., 1998). RA
differs from OA and FM in several important ways (see
Table 8.1). First, RA is an autoimmune disease characterized
by systemic attacks by immune cells on the synovial tissue
lining the joints of the body. As a result of chronic in”amma-
tion, the synovial lining of affected joints becomes saturated
with lymphocytes, cytokines, and other pro-in”ammatory
cells. These cells in turn release substances that sustain the
in”ammatory responses. The in”ammation at af fected joints
typically causes swelling and tenderness. Over time, the
chronic in”ammation eventually erodes the surrounding car-
tilage, bone, and ligaments, resulting in loss of function in the
affected joint (Harris, 1993).
In RA, disease sequelae often directly produce the most
common symptoms. Aside from the joint swelling and tender-
ness characteristic of in”ammation, other common symptoms
of RA include pain, morning stiffness, and fatigue (Harris,
1993). Joints most commonly affected in RA are the proxi-
mal interphalangeal (PIP), metacarpophalangeal (MCP), and
wrist joints. As the disease progresses, larger joints become
more symptomatic. Another de“ning feature of RA is the
widespread, symmetric involvement of joint in”ammation.
Although joint tenderness and swelling may initially appear
asymmetric, more symmetric involvement occurs as the dis-
ease progresses (Harris, 1993).TABLE 8.1 Characteristics of RA, OA, and FM
RA OA FMPathology Autoimmune disease: In”ammation Imbalance of cartilage destruction Unknown: Possible CNS dysregulation
of synovial lining of joints and repair. of neurohormonal or
leads to destruction of joint. pain-transmitting substances.
In”ammation Systemic. Local. Not present.
Distribution Widespread and usually symmetric. Localized, usually weight-bearing joints Widespread and symmetric.
affected “rst.
Areas commonly Proximal interphalangeal (PIP), Hips, knees, spine, hands, and feet. Tender points.
affected metacarpophalangeal (MCP),
and wrist joints.
Genetic component Present. Present. Present.
Lab measures Radiographic and immune markers Radiographic. Tender point exam.
of in”ammation.
Epidemiology More prevalent in women; Hand, knee, and generalized OA more More prevalent in women; increases
increases with age. common in women; hip OA more with age.
common in men; increases with age.