Prognosis 377PROGNOSIS
Knowledge about the course and long-term prognosis of CFS
has been increasing. Duration of illness has been mentioned
as a possible predictor of recovery by several investigators.
Recovery rates for individuals in the Reyes et al. (1999) sam-
ple were impacted by duration of illness at time of enrollment
in the study, with individuals with shorter duration of illness
at time of enrollment being more likely to report recovery.
Consistent with the “ndings of Reyes et al. (1999), other
researchers (Clark et al., 1995; Ray, Jeffries, & Weir, 1997)
determined that persistent illness and poorer outcomes could
be predicted by longer duration of CFS symptoms. Wilson
and associates (1994), however, did not “nd duration of ill-
ness to be a predictor of outcome, and Hill and associates
(1999) found that neither duration of illness nor mode of
onset predicted illness outcome.
In a community sample, Jason, Taylor, Kennedy, Song,
et al. (2000) found that individuals with a shorter duration of
illness perceived their health as better and had a more opti-
mistic outlook regarding recovery than those with longer
illness duration. In contrast to these differences in overall
perceptions of health, however, analyses of outcome mea-
sures revealed that the severity of most CFS symptoms re-
mained stable throughout the course of the illness, regardless
of duration. Taken together, these two “ndings may indicate
that individuals with shorter illness duration, though just as
ill as those with longer duration, are more likely to be opti-
mistic about overall self-perceived health and prognosis.
Follow-up studies generally suggest that illness attribution
and coping styles are important predictors of long-term out-
come in CFS. Wilson and associates (1994) conducted a
three-year follow-up study of patients previously enrolled in
a placebo-controlled treatment study. These researchers
found that many remain functionally impaired over time.
Psychological factors were found to be important determi-
nants of outcome such that participants who cope with
distress by somatization (presenting physical rather than psy-
chological symptoms) and discount the possible modulating
role of psychosocial factors are more likely to have an unfa-
vorable outcome. Russo and colleagues (1998) followed ter-
tiary care clinic patients with chronic fatigue for two and a
half years and found that patients whose psychiatric disorders
and physical examination signs were still present at follow-
up were more likely to have persistent fatigue and work
disability. Clark and associates (1995) also followed tertiary
care clinic patients and found that the factors that predicted
persistent illness in chronic fatigue patients included having
more than eight medically unexplained physical symptoms, a
lifetime history of dysthymia, a duration of chronic fatigue
that was more than one and a half years, less than 16 years of
formal education, and age over 38 years. Sharpe, Hawton,
Seagroatt, and Pasvol (1992) conducted a follow-up of ter-
tiary care patients six weeks to four years after initial clinic
visit and similarly found that longer illness duration, belief in
a viral cause of the illness, limiting exercise, changing or
leaving employment, belonging to a self-help organization,
and current emotional disorder predicted greater functional
impairment.
Bombardier and Buchwald (1995) compared functional
outcomes in patients with chronic fatigue and CFS and found
that individuals who met the Holmes et al. (1988) de“nition
of CFS had poorer prognosis than individuals who did not
meet CFS criteria. Similar to the Clark et al. (1995) study, the
coexistence of dysthymia predicted poorer outcome across
groups. Kroenke, Wood, Mangelsdorff, Meier, and Powell
(1988) conducted a one-year follow-up and found that a mi-
nority (28%) of CFS patients improved. Consistent with “nd-
ings of other studies, older patients and individuals with
higher scores on a measure of functional impairment had a
poorer prognosis at follow-up. Vercoulen and associates
(1996) found that improvement in CFS was related to a sense
of control over symptoms and to not attributing the illness to
physical causes.
Reyes et al. (1999) found that those who recovered from
CFS were similar demographically to those who remained ill.
Taylor, Jason, and Curie (2001) examined predictors of in-
creased fatigue severity and predictors of continued chronic
fatigue status at a follow-up within a random community-
based sample of individuals previously evaluated in a preva-
lence study of chronic fatigue and CFS. Findings revealed
that baseline fatigue severity was the only variable that pre-
dicted increased fatigue severity at the follow-up in the over-
all sample of individuals with and without chronic fatigue. In
the smaller sample of individuals with chronic fatigue, base-
line fatigue severity, worsening of fatigue with physical exer-
tion, and feeling worse for 24 hours or more after exercise
signi“cantly predicted continued chronic fatigue status (ver-
sus improvement) at follow-up. Camacho and Jason (1998)
compared individuals who had recovered from CFS versus
those that had not. Analyses show no signi“cant dif ferences
between groups on measures of optimism, stress, and social
support, although a few signi“cant dif ferences were noted
on measures of fatigue and coping. Not surprisingly, those
who had recovered from CFS had less fatigue and spent less
time focusing on symptoms than those who had not recov-
ered. Those who had recovered in comparison to healthy con-
trols more often used positive reinterpretation and growth