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Evaluating the Centers for Disease Control's Empirical Chronic Fatigue Syndrome Case Definition

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The Centers for Disease Control and Prevention (CDC) recently developed an empirical case definition that specifies criteria and instruments to diagnose chronic fatigue syndrome (CFS) in order to bring more methodological rigor to the current CFS case definition. The present study investigated this new definition with 27 participants with a diagnosis of CFS and 37 participants with a diagnosis of a Major Depressive Disorder. Participants completed questionnaires measuring disability, fatigue, and symptoms. Findings indicated that 38% of those with a diagnosis of a Major Depressive Disorder were misclassified as having CFS using the new CDC definition. Given the CDC’s stature and respect in the scientific world, this new definition might be widely used by investigators and clinicians. This might result in the erroneous inclusion of people with primary psychiatric conditions in CFS samples, with detrimental consequences for the interpretation of epidemiologic, etiologic, and treatment efficacy findings for people with CFS.
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1
Evaluating the Centers for Disease
Control’s Empirical Chronic Fatigue
Syndrome Case Definition
Leonard A. Jason
Natasha Najar
Nicole Porter
Christy Reh
DePaul University, Chicago, Illinois
The Centers for Disease Control and Prevention (CDC) recently developed an empirical case definition that specifies
criteria and instruments to diagnose chronic fatigue syndrome (CFS) in order to bring more methodological rigor to the
current CFS case definition. The present study investigated this new definition with 27 participants with a diagnosis of CFS
and 37 participants with a diagnosis of a Major Depressive Disorder. Participants completed questionnaires measuring
disability, fatigue, and symptoms. Findings indicated that 38% of those with a diagnosis of a Major Depressive Disorder
were misclassified as having CFS using the new CDC definition. Given the CDC’s stature and respect in the scientific
world, this new definition might be widely used by investigators and clinicians. This might result in the erroneous inclusion
of people with primary psychiatric conditions in CFS samples, with detrimental consequences for the interpretation of
epidemiologic, etiologic, and treatment efficacy findings for people with CFS.
Keywords: chronic fatigue syndrome; empirical case definition; Centers for Disease Control and Prevention; Fukuda criteria;
Major Depressive Disorders
Chronic fatigue syndrome (CFS) is a disabling
chronic illness that has been defined by a consensus-
based approach by Fukuda et al. (1994). This case defi-
nition specifies that individuals with this illness must
have 6 or more months of chronic fatigue of new or def-
inite onset, which is not substantially alleviated by rest,
is not the result of ongoing exertion, and results in sub-
stantial reductions in occupational, social, and personal
activities. In addition, to be diagnosed with this illness,
individuals must have four or more symptoms (i.e., sore
throat, lymph node pain, muscle pain, joint pain, postex-
ertional malaise, headaches of a new or different type,
memory and concentration difficulties, and unrefreshing
sleep) that persist 6 or more months since onset.
Although the Fukuda et al. case definition continues to
be widely used, several articles have identified difficul-
ties that this case definition continues to pose to clini-
cians and researchers (Jason, King, et al., 1999; Reeves
et al., 2003). For example, the Fukuda et al. case defin-
ition did not specify which instruments to use and did not
provide empirically derived cutoff points and scoring
guidelines to diagnose CFS.
The Centers for Disease Control and Prevention
(CDC) has now developed an empirical case definition
for CFS that involves assessment of symptoms, disabil-
ity, and fatigue (Reeves et al., 2005). The new CDC
empirical case definition assesses disability using the
Medical Outcomes Survey Short-Form-36 (Ware, Snow,
& Kosinski, 2000), assesses symptoms using the
Symptom Inventory (Wagner et al., 2005), and assesses
fatigue using the Multidimensional Fatigue Inventory
(Smets, Garssen, Bonke, & DeHaes, 1995). The authors
of this empirical case definition feel that the specifica-
tion of instruments and cutoff points would result in a
more reliable and valid approach for the assessment of
CFS. Using these new criteria, the estimated rate of CFS
has increased to 2.54% (Reeves et al., 2007), a rate that
is about 10 times higher than prior CDC estimates
(Reyes et al., 2003) and prevalence estimates of other
Journal of Disability
Policy Studies
Volume XX Number X
Month XXXX xx-xx
© 2008 Hammill Institute
on Disabilities
10.1177/1044207308325995
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hosted at
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Authors’ Note: Address correspondence to Leonard A. Jason, PhD,
Director, Center for Community Research, DePaul University, 990
W. Fullerton Avenue, Suite 3100, Chicago, IL 60614; e-mail:
Ljason@depaul.edu.
Journal of Disability Policy Studies OnlineFirst, published on October 21, 2008 as doi:10.1177/1044207308325995
investigators (Jason, Richman, et al., 1999). It is of
interest that the new CFS rates are within the range of
several mood disorders. Mood disorders are the most
prevalent psychiatric disorders after anxiety disorders:
For a major depressive episode, the 1-month prevalence
is 2.2%, and lifetime prevalence is 5.8% (Regier, Boyd,
& Burke, 1988). It is at least possible that the increases
in the United States are due to a broadening of the case
definition and possible inclusion of cases with primary
psychiatric conditions. CFS and depression are two dis-
tinct disorders, however, even if they share a number of
common symptoms. Including patients with a primary
psychiatric illness in the current CFS case definition
could confound the interpretation of epidemiologic and
treatment studies. Major Depressive Disorder (MDD) is
an example of a primary psychiatric disorder that has
some overlapping symptoms with CFS.
Fatigue, sleep disturbances, and poor concentration
occur in both depression and CFS. It is important to dif-
ferentiate those with a principal diagnosis of MDD from
those with CFS only. This is particularly important
because it is possible that some patients with MDD also
have chronic fatigue and four minor symptoms that can
occur with depression (e.g., unrefreshing sleep, joint
pain, muscle pain, and impairment in concentration).
Fatigue and these four minor symptoms are also defining
criteria for CFS. It is possible that using this broadened
new CFS empirical case definition (Reeves et al., 2005),
some patients with a primary affective disorder could be
misdiagnosed as having CFS. Some CFS investigators
would not see this as a problem because they believe that
CFS is mainly a psychiatric disorder and that distinctions
between the two phenomena are superficial and merely a
matter of nomenclature. However, several CFS symp-
toms, including prolonged fatigue after physical exer-
tion, night sweats, sore throats, and swollen lymph
nodes, are not commonly found in depression. In addi-
tion, although fatigue is the principal feature of CFS,
fatigue does not assume equal prominence in depression
(Friedberg & Jason, 1998; Komaroff et al., 1996).
Moreover, illness onset with CFS is often sudden, occur-
ring over a few hours or days, whereas primary depres-
sion generally shows a more gradual onset. Individuals
with CFS can also be differentiated from those with
depression by recordings of skin temperature levels and
electrodermal activity (Pazderka-Robinson, Morrison, &
Flor-Henry, 2004). Hawk, Jason, and Torres-Harding
(2006) used discriminant function analyses to identify
variables that successfully differentiated patients with
CFS, MDD, and controls. Using percentage of time
fatigue was reported, postexertional malaise severity,
unrefreshing sleep severity, confusion/disorientation
severity, shortness of breath severity, and self-reproach
to predict group membership, 100% were classified cor-
rectly. In summary, CFS and depression are two distinct
disorders, although they share a number of common
symptoms. It is possible to appropriately differentiate
MDD from CFS if one uses appropriate measures.
It is still unclear whether the new empirical case defi-
nition of CFS (Reeves et al., 2005) has inappropriately
included cases of purely affective disorders, such as
MDD. This study evaluated whether the CDC empirical
case definition distinguished between persons with
MDD and persons with CFS. By assessing samples with
MDD and CFS, we hoped to clarify whether the CDC
empirical case definition has been able to successfully
differentiate those with MDD from those with CFS.
Method
Participants
We recruited a total of 64 individuals, 27 with CFS and
37 with MDD. We obtained our sample of participants
with CFS from two sources: local CFS support groups in
Chicago and a previous research study conducted at
DePaul University. To be included in the study, partici-
pants were required to have been diagnosed with CFS,
using the Fukuda et al. (1994) diagnostic criteria, by a
certified physician and were required to currently meet
CFS criteria using the Fukuda et al. criteria. We excluded
individuals who had other current psychiatric conditions
in addition to major depression or who reported having
untreated medical illnesses (e.g., diabetes, anemia).
We solicited 37 participants with a diagnosis of MDD
to participate in this study. We found participants from
three sources: local chapters of the Depression and
Bipolar Support Alliance group in Chicago; Craigslist, a
free local classified ads forum that is community moder-
ated; and online depression support groups. To be
included in the study, all participants were required to
have been diagnosed with MDD by a licensed psycholo-
gist or psychiatrist. We excluded individuals who had
other current psychiatric conditions in addition to MDD
(e.g., bipolar, schizophrenia) and those who reported
having untreated medical illnesses.
Participants who met criteria completed question-
naires that are described below. Participants reported any
previous physical and mental illnesses and the date of
diagnosis as well as current medications being taken to
ensure that no other illness could account for the fatigue.
We carefully screened participants to ensure that partici-
pants from the MDD group did not have CFS as defined
by the Fukuda et al. (1994) criteria.
2 Journal of Disability Policy Studies
Measures
Demographic variables. We collected basic demo-
graphic variables that included age, ethnicity, marital
status, occupation, gender, work status, and educational
level.
The Medical Outcomes Survey Short-Form-36. This
36-item instrument is composed of multi-item scales that
assess functional impairment in eight areas: limits in
physical activities (Physical Function), limits in one’s
usual role activities due to physical health (Role Physical),
limits in one’s usual role activities due to emotional health
(Role Emotional), Bodily Pain, general health perceptions
(General Health), vitality (Energy and Fatigue), Social
Function, and General Mental Health (Ware et al., 2000).
Scores in each area reflect ability to function, and higher
values indicate better functioning. Reliability and validity
studies have demonstrated high reliability and validity in a
wide variety of patient populations for this instrument
(Stewart, Greenfield, Hays, et al., 1989). Based on the
CDC empirical case definition (Reeves et al., 2005), the
Medical Outcomes Survey Short-Form-36 was used to
assess disability (Wagner et al., 2005). According to
Reeves et al. (2005), significant reductions in occupa-
tional, educational, social, or recreational activities were
defined as scores lower than the 25th percentile on
Physical Function (less than or equal to 70), or Role
Physical function (less than or equal to 50), or Social
Function (less than or equal to 75), or Role Emotional
function (less than or equal to 66.7). A person would meet
the disability criterion for the empirical CFS case defini-
tion by showing impairment in only one or more of these
four areas (Reeves et al., 2005).
The CDC Symptom Inventory. The CDC Symptom
Inventory assesses information about the presence, fre-
quency, and intensity of 19 fatigue-related symptoms dur-
ing the past 1 month (Wagner et al., 2005). All 8 of the
critical Fukuda et al. (1994) symptoms were included as
well as 11 other symptoms (e.g., diarrhea, fever, sleeping
problems, and nausea). For each of the 8 Fukuda et al.
symptoms, participants were asked to report the frequency
(1 = a little of the time,2 = some of the time,3 = most of
the time,4 = all of the time) and severity (the ratings were
transformed to the following scale: .08 = very mild, 1.6 =
mild, 2.4 = moderate, 3.2 = severe,4 = very severe; see
Note 1). The frequency and severity scores were multi-
plied for each of the 8 critical Fukuda et al. symptoms and
were then summed. Participants having 4 or more symp-
toms and scoring greater than or equal to 25 would meet
symptom criteria on this instrument according to the CDC
empirical case definition (Reeves et al., 2005).
The Multidimensional Fatigue Inventory. This instru-
ment is a 20-item self-report instrument consisting of
five scales: General Fatigue, Physical Fatigue, Reduced
Activity, Reduced Motivation, and Mental Fatigue
(Smets et al., 1995). Each scale contains four items
rated from 1 to 5, with the scale score of 1 meaning yes,
that is true and the scale score of 5 meaning no, that is
not true. Reeves et al. (2005) used the Multidimensional
Fatigue Inventory to measure severe fatigue, and to do
this, they used only two of the five subscales: General
Fatigue and Reduced Activity. Using the CDC empirical
case definition standards, severe fatigue was defined as
greater than or equal to 13 on General Fatigue or less
than or equal to 10 on Reduced Activity.
Results
Classification by CDC Empirical Case
Definition Criteria
When using the CDC empirical case definition to classify
people with CFS, all 27 participants in the CFS-recruited
group met criteria for CFS. However, 14 additional individ-
uals from the MDD group also met the new CDC criteria
for CFS. That is, 38% of those with a professional diagno-
sis of major depression were misclassified as having CFS
using the CDC empirical case definition.
Sociodemographic Variables
Participants were separated into three groups: Those
27 diagnosed with CFS prior to this study and who met
the new empirical CDC case definition of CFS, those 14
from the group with MDD meeting the new empirical
CDC case definition of CFS criteria (MDD/CFS), and
those 23 from the group with MDD not meeting the new
empirical CDC criteria for CFS (MDD). Sociodemographic
data were compared across all three groups of partici-
pants using Pearson’s χ2and analysis of variance
(ANOVA; see Table 1). Findings indicated a significant
age effect, F(2, 63) = 3.25, p <.05. The average age for
the CFS group was significantly older than the MDD/
CFS group. Furthermore, there were also significant
differences in regard to work status between groups,
χ2(6, N= 64) = 13.92, p<.05. More individuals in the
CFS group were on disability as compared to the MDD/
CFS group, χ2(1, N= 41) = 4.11, p <.05.
Illness Classification by Standardized
Clinically Empirical Criteria
Medical Outcomes Survey Short-Form-36. According
to the CDC empirical case definition, participants are
required to demonstrate functional impairment within
one of the four areas: Physical Function, Role Physical,
Role Emotional, and Social Function. One-way ANOVA
Jason et al. / CDC Empirical Case Definition 3
was used to assess the effect of physical impairment
within four subscales of the Medical Outcomes Survey
Short-Form-36 for the three groups (CFS, MDD, and
MDD/CFS). As seen in Table 2, there were significant
effects for three of the subscales, but not social function-
ing. Using Tukey’s honestly significant difference (HSD)
post hoc test, significant differences were found for Role
Physical; participants with CFS had significantly lower
scores compared to both the MDD group (p<.001) and
the MDD/CFS group (p<.001). In regard to physical
functioning, the participants with CFS had significantly
worse Physical Function impairment scores in compari-
son to participants with MDD (p>.001) and participants
with MDD/CFS (p <.001). Finally, for role emotional
functioning, the MDD/CFS group scored significantly
lower on the Role Emotional scale than both the CFS
(p <.001) and the MDD groups (p<.001).
Examining Table 3, it is apparent that all three illness
groups met criteria for at least one of the four subscales
and thus would meet the disability criteria for the empir-
ical case definition of CFS. It is clear that significantly
more participants from the MDD and MDD/CFS groups
met Role Emotional criteria than the CFS group.
However, if Role Physical or Physical Functioning cri-
teria were used as the sole criterion for disability, sig-
nificantly more participants within the CFS group
would meet the disability criteria than those in the
MDD/CFS and MDD groups.
Symptom Inventory analysis. There was a significant
effect of the total CFS symptom scores, F(2, 61) =
34.184, p<.001. The MDD group had the lowest mean
score, indicating that this group did not likely meet cri-
teria for CFS. The CFS group mean score was direction-
ally but not significantly higher than the MDD/CFS
group score. Tukey post hoc tests indicated that the CFS
and MDD/CFS groups scored significantly higher than
the MDD group (p<.001). Examining Table 3, both the
CFS and MDD/CFS groups had higher percentages of
participants meeting CFS symptom criteria than those in
the MDD group. The fact that 100% of participants in the
CFS and MDD/CFS groups met criteria for this index
suggests that many individuals without CFS will meet
these cutoff criteria for symptom frequency and severity.
4 Journal of Disability Policy Studies
Table 1
Sociodemographic Characteristics Between the CFS, MDD/CFS, and MDD Groups
CFS MDD/CFS MDD
Characteristic n%M (SD) n %M (SD) n %M (SD) Significance
Age 27 49 (13.2) 14 37 (12.3) 23 44 (15.5)
Gender
Male 2 7 1 7 3 13
Female 25 93 13 93 20 87
Race
White 19 70 11 79 17 74
Black 5 19 2 14 0 0
Other 3 11 1 7 6 26
Marital status
Married 7 26 3 21 4 17
Never married 11 41 8 57 15 65
Separated/widowed/divorced 9 33 3 21 4 17
Children
Yes 17 63 5 36 8 35
No 10 37 9 64 15 65
Education
High school degree or less 2 7 2 14 4 17
Partial training 9 33 8 57 6 26
College degree 8 30 3 21 7 30
Grad/profession 8 30 1 7 6 26
Work status
On disability 13 48 3 21 3 13 *
Unemployed 4 15 2 14 7 31
Work part-time 5 18 2 14 1 4
Work full-time 5 18 7 50 12 52
Note: CFS = chronic fatigue syndrome; MDD = major depressive disorder.
*Difference is statistically significant at the p.05 level.
The Multidimensional Fatigue Inventory. The CDC
empirical case definition used the Multidimensional
Fatigue Inventory to measure fatigue. There was a sig-
nificant effect for General Fatigue, F(2, 61) = 4.89, p<
.05, but no significant effect was found for Reduced
Activity. Post hoc analysis using the Tukey HSD test
revealed significant differences for General Fatigue. The
MDD group scored significantly lower on the General
Fatigue scale than both the CFS (p<.01) and MDD/CFS
groups (p<.01). Inspecting Table 3, all participants
within the CFS and MDD/CFS groups met one of the
fatigue criteria. In addition, 87% of those in the MDD
group also met one of the fatigue criteria. This again sug-
gests that for the domain of fatigue, the empirical case
criteria will select many individuals without CFS who will
meet fatigue criteria for the empirical case definition.
Discussion
Reeves et al. (2005) claim that the empirical defini-
tion identifies people with CFS in a more precise manner
than can occur in the more traditional way of diagnosis.
Analyses from this study reveal that the new empirical
case definition identified 38% of the MDD group as
meeting CFS criteria. Cantwell (1996) argues that diag-
nostic criteria should specify which diagnostic instru-
ment to use, what type of informants to interview, and
how to determine the presence and severity of the crite-
ria. The effort by Reeves et al. to specify a certain
number and type of symptoms that should be present in
order to make a particular diagnosis appears to be over-
inclusive, particularly for those having a primarily
depressive disorder.
An analysis of the Medical Outcomes Survey Short-
Form-36 illustrates the problems with the cutoff criteria.
When using the Reeves et al. (2005) cutoff points to
classify functional impairment, all three groups (100%)
met criteria for this instrument in Table 3. However, had
Reeves et al. selected either Physical Function or Role
Physical, better differentiation would have occurred, as
there is a significant difference between the CFS group
and the other two groups for these domains. Because
individuals need only to score lower than the 25th per-
centile in one of these four areas in order to meet the
CFS criteria, individuals might not have any reductions
in key areas of physical functioning and only impairment
in role emotional areas (e.g., problems with work or
other daily activities as a result of emotional problems).
Jason et al. / CDC Empirical Case Definition 5
Table 2
Mean Differences Between the CFS, MDD/CFS, and MDD Groups on Criteria Variables
CFS MDD/CFS MDD
Variable M(SD)M(SD)M(SD) Significance
Medical Outcomes Survey Short-Form-36
Role Physical 5.56 (16.01)a,b 51.79 (40.98)b58.7 (45.61)a***
Social Function 30.09 (28.43) 41.96 (23.31) 40.22 (25.27)
Physical Function 37.41 (23.43)a,b 70.36 (32.90)b76.74 (21.25)a***
Role Emotional 69.14 (40.22)a,b 19.05 (31.25)a30.43 (40.09)b***
CDC Symptom Inventory
CDC scores 43.97 (14.28)b37.56 (10.54)a17.05 (8.62)a,b ***
Multidimensional Fatigue Inventory
General Fatigue 16.74 (2.90)b16.86 (2.80)a14.3 (3.42)a,b **
Reduced Activity 14.44 (3.79) 13.64 (3.95) 13.17 (4.77)
Note: Similar letter subscripts across rows indicate significant differences in means. CFS = chronic fatigue syndrome; MDD = major depres-
sive disorder.
**Difference is statistically significant at the p.01 level. ***Difference is statistically significant at the p.001 level.
Table 3
Percentages of the CFS, MDD/CFS, and MDD
Groups Meeting Specific CFS Criteria
Criteria %CFS %MDD/CFS %MDD Significance
Medical Outcomes Survey
Short-Form-36
Role Physical 50.0 96a,b 50a44b***
Social Function 75.0 96 100 91
Physical Function 70.0 93a,b 43a35b***
Role Emotional 66.7 44a,b 93a78b***
Meets at least 1 100 100 100
CDC Symptom Inventory
CDC scores 25.0 100a100b9a,b ***
Multidimensional Fatigue
Inventory
General Fatigue 13.0 93 93 74
Reduced Activity 10.0 85 86 78
Meets at least 1 100 100 87
Note: Similar letter subscripts across rows indicate significant differ-
ences in means. CFS = chronic fatigue syndrome; MDD = major
depressive disorder.
***Difference is statistically significant at the p.001 level.
For Role Emotional, 93% of the MDD/CFS group and
78% of the MDD group met criteria, a percentage much
higher than the CFS group (44%). Ware et al. (2000)
found that the mean for Role Emotional for a clinical
depression group was 38.9, indicating that almost all
those with clinical depression would meet criteria for
being within the lower 25th percentile on this scale
(which was a score of less than or equal to 66.7). In addi-
tion, King and Jason (2005) compared a group diagnosed
with CFS and a group diagnosed with MDD, and the lat-
ter group had lower scores than the group with CFS (37.8
vs. 48.9), but both groups would have met the CDC cri-
teria as they both scored below 66.7. In contrast, if the
criterion was a score lower than the 25th percentile on
just Physical Function (less than or equal to 70), the par-
ticipants with CFS would have met this criterion as their
average score was 44, whereas many within the MDD
group would have not met this criterion as their average
score was 70.3.
Regarding the Symptom Inventory, 100% of both the
CFS and MDD/CFS groups met criteria, indicating this
instrument did not distinguish the individuals with CFS
from individuals with major depression. It is probable
that the Symptom Inventory misclassified the MDD/CFS
group for several reasons. For example, the Symptom
Inventory asks about the symptom occurrences within
the past month rather than the past 6 months, as required
by the Fukuda et al. (1994) case definition. The require-
ment for a participant to report a symptom for 1 month
might include more individuals within the CFS category
(e.g., a person who has experienced a physical illness
such as influenza or a head cold could very well have
experienced a severe sore throat for the past month).
Even with summed scores for the empirical case defini-
tion needing to be greater than or equal to 25 (Reeves
et al., 2005), the overall level of symptoms might be rela-
tively low for patients with classic CFS symptoms (the
criterion would be met if an individual rated only two
symptoms as occurring all the time, and one was of mod-
erate and the other of severe severity). Similarly, a
person with MDD could endorse symptoms that would
easily meet criteria for this scale, such as unrefreshing
sleep, impaired memory, and headaches, and muscle pain
at a moderate to severe level. However, the most impor-
tant factor is that the Symptom Inventory does not distin-
guish critical symptoms for CFS such as postexertional
malaise, unrefreshing sleep, and cognitive difficulties.
Each symptom is given the same value, which means
that a participant reporting severe and frequent
headaches is given the same value as a participant report-
ing severe and frequent postexertional malaise. Overall,
14 individuals diagnosed with MDD scored 25 or higher
on the Symptom Inventory and reported four or more
symptoms. This demonstrates that individuals with pri-
mary psychiatric illnesses are not always excluded using
the CDC Symptom Inventory.
The Multidimensional Fatigue Inventory was used to
measure severe fatigue, yet 93% of both the CFS and
MDD/CFS groups met criteria for General Fatigue,
while 74% of the MDD group did as well. As for the cri-
teria that Reeves et al. (2005) used, the primary devel-
oper of the Multidimensional Fatigue Inventory had this
to say: “Regarding the criteria suggested by Reeves, we
have no paper to back up their decision, but scanning
their paper it appears that they used the median of their
own data” (E. M. Smets, personal communication, June
29, 2006). In one study of three groups with CFS, the
mean Multidimensional Fatigue Inventory General
Fatigue scores were 18.3 to 18.8 (Tiersky, Matheis,
DeLuca, Lange, & Nateson, 2003). When assessing
Reduced Activity, 85% and 86% of both the CFS and
MDD/CFS groups (respectively) met criteria, as did 78%
of the MDD group. Therefore, 100% of the CFS and
100% of the MDD/CFS group met the CDC fatigue cri-
teria. The problem with this instrument is that it is rela-
tively easy to meet criteria for one of the two categories.
In other words, a depressed person could easily respond
positively to questions such as “I get little done” or “I do
very little in a day” and answer negatively to “I feel very
active” or “I think I do a lot in a day.” Consequently, a
depressed person would meet CFS criteria by answering
“entirely true” to these types of items.
Inspecting the scores of a person with MDD who was
inappropriately classified as having CFS highlights the
problems with the CDC empirical criteria. A 26-year-old
female with MDD met criteria for CFS using the CDC
empirical case criteria (Reeves et al., 2005). For the
Medical Outcomes Survey Short-Form-36, she met cutoff
points for Social Function (scoring 37.5 when needing to
score 75) and Role Emotional (scoring 0 when needing
to score 66.7). With a clinical diagnosis of MDD, she
demonstrated impairment with social and emotional
functioning, two important traits of depression. This
person scored 100 on Physical Function, which is the
highest possible score on this measure, indicating that
she had no difficulties with physical functioning, which
would be a clear indicator that she did not have CFS. On
the CDC Symptom Inventory, she reported that postexer-
tional malaise was mild only some of the time, indicat-
ing that she did not have this cardinal symptom of CFS.
For this individual and others within the MDD/CFS
group, the instruments used to identify cases of CFS did
not adequately exclude persons with primary psychiatric
disorders.
6 Journal of Disability Policy Studies
Study Limitations
There were biases in using a convenience sample, and
recruitment from a population-based referral source
would have been preferable, but such samples are expen-
sive to recruit. Also, the sample sizes overall were rela-
tively small, but even though power was low to detect
differences, we were able to find a number of significant
outcomes, as represented in Tables 2 and 3. In addition,
we focused on only one psychiatric disorder, and future
studies might include anxiety disorders, which might
also be misclassified. In addition, there is probably a
redundancy in some of our findings, as some of the
scales are correlated.
There are other ways that might be used to develop
improvements in the CFS case definition. As an example,
Jason, Corradi, and Torres-Harding (2007) factor analyzed
the core symptoms as defined by the Fukuda et al. (1994)
criteria, but this did not result in interpretable factors.
However, when they included a larger group of theoreti-
cally defined symptoms in the factor analyses, an inter-
pretable set of factors did emerge. The following factors
were found: neurocognitive (e.g., slowness of thought),
vascular (e.g., dizzy after standing), inflammation (e.g.,
chemical sensitivities), muscle/joint (e.g., pain in multiple
joints), infectious (e.g., sore throat), and sleep/postexer-
tional (e.g., unrefreshing sleep). These findings suggest
that theoretical and empirical approaches to determining
critical symptoms of CFS have considerable merit. The
field of CFS studies needs to be grounded in empirical
methods for determining a case definition versus more
consensus-based efforts.
In conclusion, this study suggests that the Reeves et al.
(2005) empirical case definition has broadened the criteria
such that some individuals with a purely psychiatric ill-
ness will be inappropriately diagnosed as having CFS. The
Reeves et al. empirical case definition used specific
instruments (such as the Medical Outcomes Survey Short-
Form-36) to make diagnostic decisions but included
dimensions within them such as role emotional function-
ing that were not specific for this illness. Green, Romei,
and Natelson (1999) found that 95% of individuals seek-
ing medical treatment for CFS reported feelings of
estrangement, and 70% believed that others uniformly
attributed their CFS symptoms to psychological causes.
Inappropriate inclusion of pure psychiatric disorders into
the CFS samples may further contribute to the diagnostic
skepticism and stigma that individuals with this illness
encounter. Several researchers continue to believe that
CFS should be considered a functional somatic syndrome
(Barsky & Borus, 1999), characterized by diffuse, poorly
defined symptoms that cause significant subjective dis-
tress and disability and that cannot be corroborated by
consistent documentation of organic pathology. Taylor,
Jason, and Schoeny (2001) have challenged this position,
but ultimately assessment and criteria that fail to capture
the unique characteristics of these illnesses might inaccu-
rately conclude that only distress and unwellness charac-
terize CFS, thus inappropriately supporting a unitary
hypothetical construct called “functional somatic syn-
drome.” Such blurring of diagnostic categories will make
it even more difficult to identify biological markers for
this illness, and if they are not identified, many scientists
will be persuaded that this illness is psychogenic (Jason &
Richman, 2008). Ultimately, using a broad or narrow def-
inition of CFS will have important influences on CFS epi-
demiologic findings, on rates of psychiatric comorbidity,
on how patients are treated, and ultimately on the likeli-
hood of finding biological markers for this illness.
Note
1. The scale we used had five choices, and we needed to convert
the ratings to a 4-point scale. We divided the five items by 4, which
came to .8. We then made each increment in value .8.
References
Barsky, A. J., & Borus, J. F. (1999). Functional somatic syndromes.
Annals of Internal Medicine,130, 910–921.
Cantwell, D. P. (1996). Classification of child and adolescent psy-
chopathology. Journal of Child Psychology and Psychiatry,37, 3–12.
Friedberg, F., & Jason, L. A. (1998). Understanding chronic fatigue
syndrome: An empirical guide to assessment and treatment.
Washington, DC: American Psychological Association.
Fukuda, K., Straus, S. E., Hickie, I., Sharpe, M. C., Donnibs, J. G., &
Komaroff, A. (1994). The chronic fatigue syndrome: A compre-
hensive approach to its definition and study. Annals of Internal
Medicine,121, 953–958.
Green, J., Romei, J., & Natelson, B. J. (1999). Stigma and chronic
fatigue syndrome. Journal of Chronic Fatigue Syndrome,5, 63–75.
Hawk, C., Jason, L. A., & Torres-Harding, S. (2006). Differential
diagnosis of chronic fatigue syndrome and major depressive dis-
order. International Journal of Behavioral Medicine,13, 244–251.
Jason, L. A., Corradi, K., & Torres-Harding, S. (2007). Toward an
empirical case definition of CFS. Journal of Social Service
Research,34, 43–54.
Jason, L. A., King, C. P., Richman, J. A., Taylor, R. R., Torres, S. R.,
& Song, S. (1999). US case definition of chronic fatigue syn-
drome: Diagnostic and theoretical issues. Journal of Chronic
Fatigue Syndrome,5, 3–33.
Jason, L. A., & Richman, J. A. (2008). How science can stigmatize:
The case of CFS. Journal of Chronic Fatigue Syndrome,14, 85–103.
Jason, L. A., Richman, J. A., Rademaker, A. W., Jordan, K. M.,
Plioplys, A. V., Taylor, R., et al. (1999). A community-based
study of chronic fatigue syndrome. Archives of Internal Medicine,
159, 2129–2137.
Jason et al. / CDC Empirical Case Definition 7
King, C., & Jason, L. A. (2005). Improving the diagnostic criteria and
procedures for chronic fatigue syndrome. Biological Psychology,
68, 87–106.
Komaroff, A. L., Fagioli, L. R., Geiger, A. M., Doolittle, T. H., Lee,
J., Kornish, R. J., et al. (1996). An examination of the working
case definition of chronic fatigue syndrome. American Journal of
Medicine,100, 56–64.
Pazderka-Robinson, H., Morrison, J. W., & Flor-Henry, P. (2004).
Electrodermal dissociation of chronic fatigue and depression:
Evidence for distinct physiological mechanisms. International
Journal of Psychophysiology,53, 171–182.
Reeves, W. C., Jones, J. J., Maloney, E., Heim, C., Hoaglin, D. C.,
Boneva, R., et al. (2007). New study on the prevalence of CFS in
metro, urban and rural Georgia populations. Population Health
Metrics,5, Article 5. Available from http://www.pophealth-
metrics.com/content/5/1/5
Reeves, W. C., Lloyd, A., Vernon, S. D., Klimas, N., Jason, L. A.,
Bleijenberg, G., et al., & the International Chronic Fatigue
Syndrome Study Group. (2003). Identification of ambiguities in
the 1994 chronic fatigue syndrome research case definition and
recommendations for resolution. BMC Health Services Research,
3, Article 25. Available from http://www.biomedcentral.com/con-
tent/pdf/1472-6963-3-25.pdf
Reeves, W. C., Wagner, D., Nisenbaum, R., Jones, J. F., Gurbaxani,
B., Solomon, L., et al. (2005). Chronic fatigue syndrome: A clin-
ically empirical approach to its definition and study. BMC
Medicine,3, Article 19. Available from http://www.biomedcen-
tral.com/content/pdf/1741-7015-3-19.pdf
Regier, D. A., Boyd, J. H., & Burke, J. D., Jr. (1988). One-month
prevalence of mental disorders in the United States: Based on five
Epidemiological Catchment Area sites. Archives of General
Psychiatry,45, 977–986.
Reyes, M., Nisenbaum, R., Hoaglin, D. C., Unger, E. R., Emmons,
C., Randall, B., et al. (2003). Prevalence and incidence of chronic
fatigue syndrome in Wichita, Kansas. Archives of Internal
Medicine,163, 1530–1536.
Smets, E. M., Garssen, B. J., Bonke, B., & DeHaes, J. C. (1995). The
Multidimensional Fatigue Inventory (MFI) psychometric properties
of an instrument to assess fatigue. Journal of Psychosomatic
Research,39, 315–325.
Stewart, A. L., Greenfield, S., Hays, R. D., Rogers, W. H., Berry, S. D.,
McGlynn, E. A., et al. (1989). Functional status and well-being
of patients with chronic conditions: Results from the medical
outcomes study. Journal of the American Medical Association,
262, 907–913.
Taylor, R. R., Jason, L. A., & Schoeny, M. E. (2001). Evaluating
latent variable models of functional somatic distress in a commu-
nity-based sample. Journal of Mental Health,10, 335–349.
Tiersky, L. A., Matheis, R. J., DeLuca, J., Lange, G., & Natelson, B. H.
(2003). Functional status, neuropsychological functioning, and
mood in chronic fatigue syndrome. Journal of Nervous and
Mental Disease,191, 324–331.
Wagner, D., Nisenbaum, R., Heim, C., Jones, J. F., Unger, E. R., &
Reeves, W. C. (2005). Psychometric properties of the CDC
Symptom Inventory for assessment of chronic fatigue syndrome.
Population Health Metrics,3, Article 8. Available from
www.pophealthmetrics.com/content/3/1/8
Ware, J. E., Snow, K. K., & Kosinski, M. (2000). SF-36 Health Survey:
Manual and interpretation guide. Lincoln, RI: Quality Metric.
Leonard A. Jason, PhD, is a professor of psychology at DePaul
University and the Director of the Center for Community Research.
His current interests include myalgic encephalomyelitis/chronic
fatigue syndrome, recovery homes, and tobacco control.
Natasha Najar, BA, currently conducts research at Northwestern
University. She has particular interests in cultural issues.
Nicole Porter, PhD, currently is the project director of a chronic
fatigue syndrome (CFS) epidemiologic grant at the Center for
Community Research, DePaul University. Her interests are in myal-
gic encephalomyelitis/CFS, meditation, and dynamic systems.
Christy Reh, BA, currently is a graduate student at the Alder School
of Professional Psychology in Chicago, Illinois.
8 Journal of Disability Policy Studies
... Reeves and colleagues [6] utilized the SF-36 to operationalize substantial reductions in functioning; they specified that patients must score at or below the 25th percentile of the general population on at least one of the following subscales: Physical Functioning, Role Physical, Social Functioning, or Role Emotional. The selection of the Role Emotional subscale was criticized, as researchers demonstrated that a majority of individuals with Major Depressive Disorder (MDD) would meet the empiric disability criterion, decreasing diagnostic specificity [9]. In further support of this critique, Jason and colleagues [9] applied ROC analysis to the SF-36 scores of individuals with ME or CFS and healthy controls; the Role-Emotional subscale had the lowest sensitivity and specificity out of all of the subscales. ...
... The selection of the Role Emotional subscale was criticized, as researchers demonstrated that a majority of individuals with Major Depressive Disorder (MDD) would meet the empiric disability criterion, decreasing diagnostic specificity [9]. In further support of this critique, Jason and colleagues [9] applied ROC analysis to the SF-36 scores of individuals with ME or CFS and healthy controls; the Role-Emotional subscale had the lowest sensitivity and specificity out of all of the subscales. ...
... This large increase would suggest that the substantial reduction criterion improves this case definition's diagnostic specificity, as the Fukuda et al. [3] CFS criteria include several symptoms may be more commonly experienced by the general population. Furthermore, this case definition's criteria are polythetic, such that participants' symptom presentations could vary widely; this method of diagnosis has shown in past studies to be problematic in diagnosing individuals with ME and CFS [9]. ...
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... If mistakes occur on these critical choice points, it is possible that individuals with other illnesses will be misdiagnosed. To illustrate this point, using the Reeves et al. (53) "empiric criteria", with its decision to use "role emotional" functioning as a measure of substantial reduction, over one-third of individuals with MDD might have been inappropriately classified as having CFS (60). These types of decisions on how to assess substantial reductions in functioning as well as other decisions such as counting a symptom as needing to occur for only 1 rather than 6 months could be responsible for the estimated 10-fold increase in CDC prevalence estimates of CFS that occurred from 2003 to 2007 (9). ...
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One of the key requirements of a reliable case definition is the use of standardized procedures for assessing symptoms. This article chronicles the development of the DePaul Symptom Questionnaire (DSQ) to assess symptoms of the major chronic fatigue syndrome (CFS) and myalgic encephalomyelitis (ME) case definitions. The original questionnaire has been modified and expanded over time to more fully capture symptoms from various adult case definitions, and a brief as well as pediatric version have also been developed. The DSQ has demonstrated very good psychometric properties in terms of test-retest reliability and sensitivity/specificity, as well as construct, predictive, and discriminant validity. The DSQ allows for a clear characterization of a patient's illness and allows scientists and clinicians to improve diagnostic reliability and validity when employing case definitions of ME and CFS.
... Their operationalization required patients to meet cutoff scores on at least one of the following subscales: Physical Functioning (≤ 70), Role Physical (≤ 50), Social Functioning (≤ 75), or Role Emotional (≤ 66.7). However, Jason, Najar, Porter, and Reh [16] found that the inclusion of the Role Emotional subscale was problematic in that it would allow an individual with primarily social or emotional impairments to receive a CFS diagnosis, and that unless there was rigorous screening prior to the use of the specified SF-36 subscales, 38% of those diagnosed with major depressive disorder would meet the Reeves et al. [13] substantial reduction requirements and thus possibly be misdiagnosed with CFS. Additionally, Jason et al. [14] evaluated each SF-36 subscale using receiver operating curves (ROC) and determined the Role Emotional subscale to be the least accurate in distinguishing patients with CFS from controls. ...
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... Their operationalization required patients to meet cutoff scores on at least one of the following subscales: Physical Functioning (≤ 70), Role Physical (≤ 50), Social Functioning (≤ 75), or Role Emotional (≤ 66.7). However, Jason, Najar, Porter, and Reh [16] found that the inclusion of the Role Emotional subscale was problematic in that it would allow an individual with primarily social or emotional impairments to receive a CFS diagnosis, and that unless there was rigorous screening prior to the use of the specified SF-36 subscales, 38% of those diagnosed with major depressive disorder would meet the Reeves et al. [13] substantial reduction requirements and thus possibly be misdiagnosed with CFS. Additionally, Jason et al. [14] evaluated each SF-36 subscale using receiver operating curves (ROC) and determined the Role Emotional subscale to be the least accurate in distinguishing patients with CFS from controls. ...
... Furthermore, the ROC findings indicated that the SF-36 subscales that assessed for impairment as a result of mental health issues (Mental Health Functioning and Role Emotional) were no better than chance at discriminating between known patients and controls in our sample. This underscores the physical nature of the impairment associated with the ME and CFS and fits with previous data that questioned the accuracy the Role Emotional component of the SF-36 in measuring substantial reduction [14,16]. In comparing different combinations of scale cutoffs, including those recommended by Jason et al. [14], it was determined that requiring cutoffs on either two out of three (YI = 0.942) or three out of four (YI = 0.941) of the top performing scales (Physical Functioning ≤ 80; General Health ≤ 47; Role Physical ≤ 25; and Social Functioning ≤ 50) resulted in equally high performing discrimination between patients and controls. ...
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... Of interest to note that repetitive blast-induced injury in war zones often causes fatigue as well as sleep disorders along with long-term cognitive deficits although somewhat differently than other forms of mTBI [19]. ...
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... In Deale and Wessely (2001), 82% of a group of CFS patients referred to a UK hospital-based specialist CFS clinic reported being prescribed antidepressants. Jason et al. found that 38% of patients with major depressive disorder were misclassified as having CFS (Jason et al., 2009). Essentially, many ME/CFS studies are vulnerable to illness misclassification, rendering evidence from these studies unreliable (Nacul et al., 2017). ...
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In 1994, researchers from the U.S. Centers for Disease Control and Prevention developed a revised case definition of chronic fatigue syndrome (CFS) (1), a complex illness characterized by debilitating fatigue and a number of accompanying flu-like symptoms. Although Fukuda and associates intended to resolve complexities surrounding the classification of individuals with CFS stemming from previous definitional criteria (1), significant problems with the revised criteria endure. This article highlights reliability issues and other conceptual and operational difficulties inherent in the current U.S. definition of CFS (1). We employ case studies derived from a community-based epidemiological study of chronic fatigue syndrome (2) to illustrate examples of the potential for misclassification of individuals with CFS using the current U.S. criteria (1). Moreover, we suggest alternative approaches to classification and ways to operationalize specific concepts embedded in the current U.S. criteria (1).
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Surveyed a group of 67 Ss (80% female, aged 18–57 yrs) seeking relief from the incapacitating symptoms of chronic fatigue syndrome (CFS) concerning their feelings of stigma and perceptions of physician attributions of CFS symptoms to psychological causes as a contributor to CFS-related stigma. Most Ss scored high on measures of stigma: 95% had feelings of estrangement, 70% believed that others attributed their CFS symptoms to psychological causes, 77% coped by using an educational strategy (disclosure), and 39% saw a need to be secretive about their symptoms in some circumstances. Most Ss (77%) were labeled as "psychological cases" by one or more of the physicians consulted, but of the 4 stigma measures, only disclosure was related to physician labeling. Such factors as duration of illness and unemployment, dissatisfaction with spouse, and symptom severity correlated significantly with measures of stigma. That many physicians were reportedly ignorant or skeptical of CFS (males more so than females) may influence attempts of CFS patients to legitimize their symptoms by disclosure and lead to high rates of health care system use. (PsycINFO Database Record (c) 2012 APA, all rights reserved)