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Emotional distress and fatigue in coronary heart disease: The global mood scale (GMS)
Psychological Medicine, 1993, vol. 23, nr. 1, pp. 111-121
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EMOTIONAL DISTRESS AND FATIGUE IN CORONARY HEART DISEASE :
THE GLOBAL MOOD SCALE (GMS)
Psychological Medicine, in press.
Center of Cardiac Rehabilitation,
University Hospital of Antwerp, Antwerp, Belgium
Address for correspondence :
UZA - Cardiale Revalidatie
Telephone : 00 32-3-829.11.11 ext. 1941
Fax : 00 32-3-829.05.20
This research was supported by a grant of the
National Fund for Scientific Research,
Running title : EMOTIONAL DISTRESS AND FATIGUE IN CHD
Evidence indicates that emotional distress has a long-term impact on morbidity and mortality in
patients with coronary heart disease (CHD), and that symptoms of depression, fatigue, and reduced
energy may identify high-risk patients. This study was designed to (1) devise a sound and practical
measure of emotional distress in CHD patients, (2) examine the relationship between emotional
distress and fatigue following CHD, and (3) examine changes in emotional distress as a function of
cardiac rehabilitation. A sample of 478 men with CHD (mean age= 57.8 ± 8.7 y) filled out
questionnaires 3-6 weeks following a myocardial infarction (N=110), bypass surgery (N=302), or
coronary angioplasty (N=66). Statistical analyses of 56 Dutch mood terms were used to produce the
20-item Global Mood Scale (GMS) which measures negative affect - characterized by fatigue and
malaise - as well as positive affect - characterized by energy and sociability - in patients with CHD.
The GMS was found to be a reliable scale (á>.90; r>.55 over a 3-month period), and correlations
with existing measures of emotional functioning and self-deception indicated its convergent and
discriminant validity. Most important, fatigue was not related to cardiorespiratory fitness in a subset
of 140 patients, but clearly was associated with negative affect. Consistent with the self-efficacy
model, scores on the GMS mood scales improved significantly as a function of rehabilitation
(p<.0001). Although symptoms of emotional distress are easily explained away by situational
factors, previous research suggests that failure to recognize the clinical significance of these
symptoms in CHD patients may result in the delay of much needed intervention. The current
findings suggest that the GMS is a theoretically and psychometrically sound measure of emotional
distress in CHD patients, and that this scale is sufficiently sensitive to assess change.
A growing body of evidence indicates that, apart from biomedical correlates of disease
severity, psychosocial variables may be related to morbidity and mortality in patients with coronary
heart disease (CHD). High levels of life stress (Ruberman et al., 1984), use of sedatives (Wiklund et
al., 1988), depression (Ahern et al., 1990; Silverstone, 1990; Ladwig et al., 1991), psychological
stress symptoms (Frasure-Smith, 1991), and somatic manifestations of emotional distress (Shekelle
et al., 1991) have been associated with an increased long-term risk for reinfarction and cardiac
mortality among post-myocardial infarction patients. Depression has also been associated with
increased morbidity and mortality in arrhythmia patients (Kennedy et al., 1987) and patients with
angiographically documented CHD (Carney et al., 1988). The similarity of results of these studies
suggests that, whether psychological stress is inferred from life circumstances or from symptoms of
distress, the negative emotions involved may have a major long-term impact in CHD patients
(Frasure-Smith, 1991). Moreover, several physiological precursors of sudden death may be
promoted by emotional distress (Kamarck & Jennings, 1991).
Unfortunately, symptoms of emotional distress are non-specific of a cardiac disease.
Emotional distress may, in fact, be associated with cardiologic complaints but not actual CHD (e.g.,
Watson & Pennebaker, 1989). Conversely, research also suggests that depression may be predictive
of CHD (e.g., Booth-Kewley & Friedman, 1987) and mortality (e.g., Murphy et al., 1987). Hence,
the role of emotional distress in the development of CHD remains controversial.
Emotional distress and fatigue. Emotional experience is characterized by two dominant
dimensions: negative and positive affect (Watson & Tellegen, 1985). Although the terms negative
and positive might suggest that these emotional factors are opposites, they are in fact largely
independent dimensions which have quite different correlates and score distributions. Negative
affect is a dimension of distress that is associated with health complaints and mental stress, while
positive affect is a dimension of energy that is associated with activity and social engagement
(Watson & Pennebaker, 1989). Positive affect displays a normal distribution of scores between
individuals, the scores being spread across a broad range of moderate values; negative affect scores,
in contrast, tend to cluster together in a small range of low values. Moreover, negative affect scores
are not likely to change within individuals, but instead tend to remain at a fairly constant low level
(Watson & Tellegen, 1985; Zevon & Tellegen, 1982).
Many patients with CHD may, however, deny negative moods (Ahern et al., 1990), but
rather may complain about feelings of fatigue (Alonzo et al., 1975; Hurst et al., 1990). In the
general population, fatigue is highly associated with emotional distress, and adults who experience
any psychological problems are at much higher risk of feeling fatigue than those who are free from
psychological problems (Chen, 1986). Research suggests that fatigue is a potential premonitory
symptom of myocardial infarction and sudden death (Alonzo et al., 1975; Appels & Mulder, 1988).
Reduced energy and disengagement from activities (i.e., low positive affect) may also be related to
cardiac arrest and mortality in patients with CHD (Ahern et al., 1990). Most important, emotional
distress following CHD is not related to the severity of cardiac disorder (Schleifer et al., 1989), but
predominantly is a function of the individual's general tendency to experience distress (Denollet,
1991 & 1992; Denollet & De Potter, 1992).
Assessment of emotional distress. Since most cardiac patients are not psychiatric patients,
traditional psychometric scales may be burdensome for CHD patients to complete. In this study,
common mood terms were therefore selected to comprise a measure of emotional distress that may
be perceived as being relevant to patients with CHD. Ideally, this scale also had to be sensitive to
changes in emotional distress as a function of intervention. Although cardiac rehabilitation
programs may reduce mortality (O'Connor et al., 1989), research largely failed to document a
psychological effect of these programs (Blumenthal et al., 1988; Taylor et al., 1986). This is an
unexpected finding because rehabilitation enhances the patient's perceived control (Krantz, 1980)
which is closely related to his or her emotional status (Litt, 1988). However, research on the
recovery process is hindered by the lack of standardized instruments that are relevant to patients
with CHD (Krantz, 1980). In view of the central role of emotional distress in recovery from CHD,
the purposes of this study are three-fold: (1) to devise a theoretically and psychometrically sound
measure of emotional distress in CHD, (2) to examine the relationship between distress, fatigue,
and objectively assessed fitness, and (3) to examine changes in emotional distress as a function of
Subject population. A sample of 478 men with CHD (mean age=57.8 years, SD=8.7) was
drawn from four hospitals: the University Hospital of Antwerp (N=284), the Middelheim (N=105)
and Sint Jozef (N=16) hospitals in Antwerp, and the Maria's Voorzienigheid hospital (N=73) in
Kortrijk (a Belgian town which is about 100 kilometers from Antwerp). Subjects of the University
Hospital were referred by their cardiologist or general practitioner to the cardiac rehabilitation
program of this hospital; subjects from the other hospitals either participated in home-based cardiac
rehabilitation (Middelheim hospital) or had no access to a rehabilitation program and received
standard medical care alone (Sint Jozef and Maria's Voorzienigheid hospitals). All subjects agreed
to participate in the study and filled out questionnaires at 3-6 weeks after one of the following
coronary events: acute myocardial infarction N=110, coronary artery bypass surgery N=302, or
percutaneous transluminal coronary angioplasty N=66.
The Antwerp rehabilitation program. The factors that determine the presence of patients
on this program are largely a function of the attitude of cardiologists and general practitioners
towards cardiac rehabilitation. The Antwerp rehabilitation program lasts 3 months and includes
exercise training, psychosocial group interventions, and individual counseling. The exercise
program comprises 36 sessions of one hour each: 24 sessions (3 x week) of exercising on different
apparatus (bicycle, treadmill, etc.) while being monitored on ECG, and 12 sessions (2 x week) of
aerobic exercise and ball games in a sports hall, this time without ECG-monitoring. The
psychosocial program comprises 6 group sessions of two hours each (1 x week) with patients and
spouses, and aims at health education, modification of risk factors, and communication about CHD.
Individual medical, dietary, and psychosocial counseling offers the opportunity to tailor the
rehabilitation program to the needs of each individual patient.
Global Mood Scale (GMS). Since all subjects were native speakers of Dutch (the present
study was conducted in the Dutch-speaking part of Belgium), this language was used to assess
subjective mood states. A list of 56 Dutch mood terms was devised to reflect the two-dimensional
model of mood (Watson & Tellegen, 1985). Statistical analyses on a subsample of 205 subjects
were used to produce an intermediate scale comprising 16 negative and 16 positive mood terms.
This scale was administered to a second subsample, and the following criteria were used to devise
the final scale: mood terms with high (1) endorsement frequency, (2) factor loading, and (3) internal
consistency were retained; mood terms with a substantial loading on both negative and positive
affect dimensions were deleted. Since samples of less than 20 descriptors may not provide an
adequate representation of the two-dimensional mood space (Watson & Tellegen, 1985), the final
version of the GMS comprises 10 negative and 10 positive mood terms that are commonly reported
by male patients with CHD. The respondent is asked to rate on a 5-point scale (ranging from not at
all to extremely) the extent to which he/she has experienced each mood state lately. An English
translation of the GMS is given in the Appendix.
Measures of emotional distress. In order to examine the extent the GMS correlates with
already accepted measures of emotional distress, a subset of 445 patients completed an abbreviated
version of the Profile of Mood States (POMS, Wald & Mellenbergh, 1990), the State-Trait Anxiety
Inventory (STAI, Van Der Ploeg et al., 1980), and the Heart Patients Psychological Questionnaire
(HPPQ, Erdman et al., 1986). The fatigue, depression, tension, and anger subscales of the
abbreviated POMS (Wald & Mellenbergh, 1990) were predicted to correlate positively with the
GMS Negative Affect dimension, while the vigor subscale was predicted to correlate positively
with the GMS Positive Affect dimension. The state subscale of the STAI (Van Der Ploeg et al.,
1980), and the well-being subscale of the HPPQ (Erdman et al., 1986) tap a broad range of pleasant
as well as unpleasant mood states (Watson et al., 1988); therefore, these subscales were predicted to
load on both affect dimensions of the GMS.
Measure of self-deception. The Marlowe-Crowne scale (Crowne & Marlowe, 1960) was
used to assess the self-deceptive factor that underlies defensiveness (Gur & Sackeim, 1979).
Although the Marlowe-Crowne scale was originally developed as a measure of social desirability,
later evidence indicates that this scale measures itself an individual difference variable which is
related to unconscious defensiveness and social adjustment (Lane et al., 1990; McCrae & Costa,
1983). Most important, coronary patients who have a high score on the Marlowe-Crowne scale tend
to remain unaware of unpleasant emotional realities (Denollet, 1991). Since self-deception is a
global personality trait that is largely independent of negative affect and positive affect dimensions
(Denollet, 1992; Denollet & De Potter, 1992), this measure of defensiveness was predicted to be
largely unrelated to the GMS scores.
Cardiorespiratory fitness. The results of a sign- or symptom- limited exercise test at 6
weeks after the coronary event were obtained in a subset of 140 patients. The WATT level
(European standard for work capacity) was predicted to be largely unrelated to the GMS scores.
Sensitivity to change. To examine the sensitivity of the GMS to changes in affect as a
function of cardiac rehabilitation, a subset of 120 patients (mean age 56.3 ± 8.2; myocardial
infarction N=55, bypass surgery N=48, coronary angioplasty N=17) filled out again the GMS at 3
months after the first assessment. Sixty patients received standard medical care at the hospital of
Kortrijk, while 60 patients completed the Antwerp rehabilitation program. Between July 1989 and
December 1990, 11 out of 125 patients dropped out of this 3-month program which includes
exercise training and psychosocial counseling. The 60 selected rehabilitation patients did not differ
from the 54 remaining patients regarding their emotional response to the program.
Statistical analyses. The frequency distribution of the Dutch mood terms was calculated in
order to isolate terms with a high endorsement rate. Multivariate analyses (Mardia et al., 1979) were
used for the development of the GMS. Item level factor analysis (principal components with
varimax rotation) was performed to examine the dimensional structure of mood terms, and the scree
plot (Cattell, 1966) was used to decide on the optimum number of factors to retain. Cronbach's á
was used to obtain internal-consistency estimates of reliability. Test-retest reliability over a 3-month
period was examined in a subset of 60 subjects receiving standard medical care. Pearson's
correlations and scale level factor analysis were used to examine the validity of the GMS, and its
descriptive characteristics were outlined. Changes in emotional distress were analyzed by repeated
measures MANOVAs with program (rehabilitation vs. control) as between-subjects factor and time
(entry vs. end score) as within-subjects factor.
FIGURE 1 Two-dimensional model of affect. Factor analysis of the 20 items comprising the
GMS indicated a marked 'elbow' that inflects at the 3th factor (Figure 1). This finding confirms the
existence of two dominant dimensions in self-reported affect that accounted for 43% and 18% of
the total variance. Succeeding factors are much smaller and roughly similar in size. The 3th, 4th,
and 5th factor, for example, only explained 6%, 5%, and 3% of the total variance, respectively.
Moreover, two out of three items comprising the 4th factor also had substantial loadings on the 1th
factor, while four out of six items comprising the 3th and 5th factors also had substantial loadings
on the 2th factor (i.e., factor loadings in the range of .35 to .55). Of course, the two-dimensional
model is not competitive with, but rather is complementary to, multifactorial models of affect
(Watson & Clark, 1992; Watson & Tellegen, 1985).
TABLE 1 Negative Affect and Positive Affect subscales of the GMS. Most mood terms were
marked positively (i.e., score>0) in at least 50% of the cases, which suggests their relevance to
CHD patients (Table 1). Negative affect was predominantly characterized by terms reflecting
fatigue/malaise, while positive affect was characterized by terms of energy/activity. Factor analysis
indicated that these mood terms are relatively pure markers of either negative or positive affect:
items had a substantial loading on one factor but a much lower loading on the other. Cronbach's á
(>.90) and corrected item-total correlations (>.50) indicated a high level of internal consistency for
both negative and positive mood terms. Items were therefore summed to comprise Negative Affect
and Positive Affect subscales (range 0-48). The reliability of these subscales over a 3-month period
was .66 and .57, respectively (N=60). In general, these findings suggest that the GMS is a sound
measure of negative and positive affect in CHD.
TABLE 2 Relationship to emotional distress, defensiveness, and fitness. The correlation of -.39
among the Negative and Positive Affect subscales indicated that they shared only 15% of their
variance (Table 2, left side). This figure does not suggest a bipolar relation between negative and
positive mood states in CHD. The correlations among the GMS Negative Affect subscale and the
fatigue, depression, and tension subscales of the abbreviated POMS (Wald & Mellenbergh, 1990)
indicated that fatigue was closely related to emotional distress in the current sample of CHD
patients. Likewise, almost 80% of the variance in the GMS Positive Affect subscale could be
explained be a psychological state of vigor. Conversely, the Negative and Positive Affect subscales
were largely independent of defensiveness (i.e., 1% of shared variance with the self-deception
scale). Factor analysis with varimax rotation clearly identified the a priori conceptualized negative
affect, positive affect, and self-deception dimensions (Table 2, right side). As predicted, the
transient distress and well-being scales loaded on both dimensions of the mood space. These
findings revealed a remarkably consistent pattern of convergent and discriminant validity. Most
important, cardiorespiratory fitness as measured by stress testing was neither related to the Negative
(r=-.02) or Positive (r=.05) Affect subscales of the GMS, nor to the Fatigue (r=-.04) or Vigor
(r=.01) subscales of the abbreviated POMS.
TABLE 3 Distribution of GMS scores. The Negative Affect and Positive Affect subscales were
neither related to age [F(1,476)=0.98 and 1.22, respectively, p>.30], nor to medical category
[F(2,475)=1.21 and 0.48, respectively, p>.30]. As could be expected, the mean Negative Affect
score was much lower than the mean Positive Affect score (Table 3). The standard deviations of
both subscales were large enough to provide an acceptable distribution of scores. The 20th, 40th,
60th, and 80th percentiles were used to divide the observed distributions into 5 categories. Intense
negative moods occur infrequently in normal subjects (Clark & Watson, 1991); however, only
frequently endorsed mood terms were selected to comprise the GMS subscales. Therefore,
differences in distribution between extrapolated GMS and POMS scores of negative affect (both
ranging from 0 to 100) were examined. The POMS score of negative affect was extrapolated from
the depression, tension, and anger subscales of the abbreviated POMS (Wald & Mellenbergh,
1990). The extrapolated mean GMS score of negative affect (=23.7) was significantly higher than
that of the POMS (=16.4) [F(1,444)=75.93,p<.0001].
Moreover, the GMS displayed a relatively normal clustering of negative affect scores
(kurtosis=0.65), whereas the POMS displayed a peaked distribution of low negative affect scores
(kurtosis=3.04). These findings suggest the possibility that CHD patients may perceive the GMS as
being more relevant than traditional measures to describe their negative mood state.
TABLE 4 Sensitivity to change. There was no significant difference between the 60
rehabilitation and 60 control subjects with reference to age, medical category, or GMS scores at
baseline. Repeated measures MANOVA indicated that changes in GMS scores over a 3-month
period were significantly different as a function of rehabilitation [F(1,118)=5.68 and 6.21,
respectively, p<.05]. Rehabilitation subjects reported a significant decrease in negative affect, and a
significant increase in positive affect (Table 4). In contrast, control subjects did not report
significant changes in affect. These findings suggest the sensitivity to change of the GMS.
This study demonstrates that the model of negative and positive affect that was primarily
observed in U.S. college students (Watson & Tellegen, 1985; Watson et al., 1988) is equally
applicable to Belgian men with CHD. Fatigue was not related to cardiorespiratory fitness, but
clearly was a marker of negative affect. Correlations among the GMS and frequently used distress
scales indicated that negative affect explained up to 50% of the variance in complaints of fatigue.
Likewise, fatigue in the general population is closely correlated with depression (e.g., Ray, 1991).
A state of depression, which is typically characterized by a combination of high negative affect and
low positive affect (Clark & Watson, 1991), may be a significant precursor of cardiac arrest and
mortality among CHD patients (Ahern et al., 1990; Carney et al., 1988; Kennedy et al., 1987;
Ladwig et al., 1991; Silverstone, 1990). Accordingly, low levels of vigor - a good marker of
positive affect in the current study - were found to predict coronary events in CHD patients (Ahern
et al., 1990). The finding that emotional distress was not related to physical fitness is consistent
with the observation that the relationship between emotional distress and morbidity/mortality
among CHD patients is independent of objective measures of disease severity and physical
condition (e.g., Ahern et al., 1990; Frasure-Smith, 1991; Ruberman et al., 1984). This implies that
vulnerability to emotion-related complications of CHD cannot be inferred from standard medical
diagnosis, and thus requires specific psychological assessment.
With reference to this issue, the research reported here has a number of limitations. The
GMS scales still need to be validated on an English-speaking population and the results of this
study need to be replicated. Moreover, the lack of data indicating the prediction of outcomes such
as coronary events makes it impossible to determine whether the dimensions assessed by the GMS
are, in fact, those which are most important. Prospective studies are needed to evaluate the ability of
the GMS to assess emotion-related mortality in CHD populations. Albeit beyond the scope of this
paper, recent studies suggest that silent myocardial ischemia and platelet activation are involved in
the long-term impact of emotional distress in CHD patients (Grignani et al., 1991; Krantz et al.,
1991). When the coronary endothelium is damaged, platelet-derived serotonin that normally elicits
vasodilatation in smooth coronary vessels instead may cause vasoconstriction (Golino et al., 1991).
Since platelet activation is associated with emotional distress, this finding may help to elucidate the
mechanism by which emotional distress contributes to coronary events in CHD patients (Dimsdale,
1991; Markovitz & Matthews, 1991).
The ability to regulate one's own mood is also an important prerequisite for maintaining a
positive self-appraisal of one's own health status (Croyle & Uretsky, 1987). Emotional distress
therefore may slow recovery from CHD (e.g., Pancheri et al., 1978). Evidence suggests, for
instance, that emotional distress is associated with failure to adhere to exercise therapy (Blumenthal
et al., 1982a) and failure to return to work (Denollet & De Potter, 1992) in CHD populations.
Psychological factors even seem to be stronger determinants of poor adaptation to CHD than
disease severity (Wiklund et al., 1984). Most important, CHD patients who report high levels of
emotional distress in the hospital or during the weeks following discharge are also likely to
experience distress later in their life (Denollet & De Potter, 1992; Frasure-Smith, 1991). These
findings stress the need for adequate measurement of emotional distress in CHD.
The current results suggest that the GMS is a reliable and valid measure of emotional
distress in CHD populations. Factor analysis provided direct evidence for the two-factor model of
affect undergirding its development (Watson & Tellegen, 1985). The GMS was also found to be a
homogeneous (á>.90) and relatively stable (r>.55 over a 3-month period) scale, and correlations
with existing measures of emotional distress indicated its convergent validity. Conversely, the GMS
was largely unrelated to self-deception. However, something more is required than mere
psychometric soundness to establish that the GMS has theoretical value. The GMS is not a
competitor with existing measures of mood such as the POMS or the Multiple Affect Adjective
Check List (MAACL, Zuckerman & Lubin, 1965), but rather is complimentary to them. Given the
overlap of the GMS with measures that are widely used in psychological research, it is important to
provide a clear rationale for the development of this new mood scale.
First, the GMS - unlike the POMS or MAACL - was devised on the basis of the two-factor
model of mood (Watson & Tellegen, 1985), and with a medical population in mind. Despite their
multifactor solutions, the high interscale correlations of both the POMS and the MAACL suggest
that a more parsimonious set of factors may exist. In fact, factor analysis of the POMS in two
samples of cancer patients (Guadagnoli & Mor, 1989), and the MAACL in one sample of
undergraduate students (Gotlib & Meyer, 1986) revealed the presence of two major components
reflecting negative and positive affect. While negative affect accounts for most of the overlap
among self-ratings of depressive and anxious symptomatology, the relative absence of positive
mood is critical in distinguishing depression from anxiety (Clark & Watson, 1991). Since
depression appears to be detrimental to recovery from CHD (e.g., Ahern et al., 1990), the ability to
reliably assess positive affect may be a promising feature of the GMS. Although other scales that
measure negative and positive affect already exist (e.g., Watson et al., 1988), they were not
designed for medical patients (Guadagnoli & Mor, 1989).
Second, the GMS and POMS differed in their threshold for endorsement of negative mood
terms. As a consequence, scores on the negative mood scales of the GMS and POMS are
differentially distributed. The high kurtosis of the POMS could be argument for using this scale,
since higher scores are likely to indicate very distressed individuals. However, the low mean POMS
scores at baseline may leave little room for improvement as a function of treatment. Accordingly,
studies that used the POMS on a test-retest basis revealed mixed evidence for the psychological
effects of exercise (Blumenthal et al., 1982b; Hughes et al., 1986). Because of the infrequent
occurrence of intense negative moods in normal subjects (Clark & Watson, 1991), only frequently
endorsed mood terms were retained to comprise the Negative Affect subscale of the GMS. This
scale has a relatively normal clustering of scores, and appears to be sensitive to change due to
sufficiently high scores at baseline. Albeit largely inconsistent with previous research (Blumenthal
et al., 1988; Taylor et al., 1986), the change in GMS scores as a function of treatment supports the
theoretical notion that cardiac rehabilitation enhances perceived control (Krantz, 1980) which in
turn may reduce emotional distress (Litt, 1988). Multidimensional rehabilitation may, in fact,
improve the emotional status of CHD patients (Dracup et al., 1991). The current findings should be
interpreted cautiously because a quasi-experimental design was used. Since cardiac rehabilitation
may be a life-saving intervention (O'Connor et al., 1989), random assignment of CHD patients to
rehabilitation and control groups is of questionable ethical value (Blodgett & Pekarik, 1987). The
lack of significant differences on demographic or dependent variables at baseline suggests the
appropriateness of the control group.
Third, short and easily repeatable measures are lacking in research on recovery from CHD.
Measures such as the POMS have a relatively long administration time (Guadagnoli & Mor, 1989),
and may be burdensome for nonclinical populations to complete (King et al., 1986). The more
burdensome the scale, the greater likelihood of it not being completed or being answered
illegitimately, which in turn can undermine a study (Gallacher & Smith, 1989). The GMS therefore
is appealing in its practicality: the measure is brief, easy to administer, and may be perceived as
being immediately relevant to CHD patients. Moreover, interpretation of scores is aided by scale
Symptoms of fatigue and general malaise are easily explained away by overwork,
psychological stress, aging, or other situational factors; as a consequence, the overall response of
patients and the medical community to these symptoms is that they are 'manageable' or that a period
of 'wait and see' is appropriate (Alonzo et al., 1975). In contrast, accumulating evidence indicates
that failure to recognize emotional distress in CHD patients may result in the delay of much needed
intervention (e.g., Frasure-Smith, 1991). Apart from treatment of standard risk factors (i.e.,
smoking, hypertension, hyperlipidemia), CHD patients can benefit from help in dealing with their
problems (Wiklund et al., 1988). Reductions in mortality associated with a stress monitoring
program and cardiovascular medication trials may, in fact, fall within the same range (Frasure-
Smith, 1991). In addition, research suggests that feelings of exhaustion (Appels & Mulder, 1988)
and depression (Booth-Kewley & Friedman, 1987) may be associated with the development of
CHD. Although this is a controversial and speculative point, it raises the possibility that
intervention programs aiming at the prevention of CHD in middle-aged subjects (De Backer et al.,
1988) may benefit from the appropriate assessment of emotional distress. On the whole, the current
findings suggest (1) that the GMS is a reliable, valid, and practical measure of emotional distress in
CHD populations, (2) that fatigue is largely unrelated to physical fitness but rather is a good marker
of negative affect in patients recovering from CHD, and (3) that the GMS is sufficiently sensitive to
assess changes in emotional distress.
I wish to thank Prof. D.L. Brutsaert and Prof. P. Van Oost for their help and support. I am
also indebted to Dr. C. Vandermersch, Dr. J. Bergen, and Dr. J. Vandenbogaerde (Maria's
Voorzienigheid Ziekenhuis, Kortrijk), Dr. E. Van Houwe (St. Jozef Ziekenhuis, Kapellen), and Dr.
P. Van Cauwelaert and Dr. P. Muylaert (Middelheim Ziekenhuis, Antwerpen) for their generous
co-operation in the research reported here.
APPENDIX: THE GLOBAL MOOD SCALE
Name: ............................................ Sex: .......... Age: .......... Date: ....................
Below are a number of words that describe different feelings and emotions. Please read each item
carefully and then circle the appropriate number next to that word. Indicate to what extent you have
felt this way lately. Please use the following scale to record your answers.
0= NOT AT ALL
To what extent have you felt this way lately :
1 Wearied → 0 1 2 3 4
2 Active → 0 1 2 3 4
3 Worn out → 0 1 2 3 4
4 Dynamic → 0 1 2 3 4
5 Bright → 0 1 2 3 4
6 Helpless → 0 1 2 3 4
7 Hard-working → 0 1 2 3 4
8 Feeble → 0 1 2 3 4
9 Lively → 0 1 2 3 4
10 Physically weak → 0 1 2 3 4
1= A LITTLE BIT 2= MODERATELY 3= QUITE A BIT 4=
11 Listless → 0 1 2 3 4
12 Tired → 0 1 2 3 4
13 Enterprising → 0 1 2 3 4
14 Relaxed → 0 1 2 3 4
15 Insecure → 0 1 2 3 4
16 Sociable → 0 1 2 3 4
17 Cheerful → 0 1 2 3 4
18 Fatigued → 0 1 2 3 4
19 Weakened → 0 1 2 3 4
20 Self-confident → 0 1 2 3 4
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Table 1 ENDORSEMENT FREQUENCY, FACTOR STRUCTURE, AND INTERNAL CONSISTENCY OF NEGATIVE AFFECT AND POSITIVE AFFECT
NEGATIVE Endorsement Factor Analysis* Internal†
AFFECT Frequency I II Consistency
Weakened 71% .82 -.17 .79
Tired 65% .88 -.12 .84
Fatigued 64% .88 -.17 .86
Physically weak 62% .86 -.12 .82
Feeble 58% .80 -.09 .75
Wearied 55% .85 -.16 .82
Insecure 51% .53 -.22 .51
Listless 43% .70 -.21 .69
Worn out 37% .85 -.11 .80
Helpless 32% .59 -.19 .56
mean eigenvalue Cronbach's
=54% I=8.60 á=.94
* Principal components analysis with varimax rotation; loadings of mood terms assigned to a factor are presented in boldface.
† Corrected item-total correlations.
POSITIVE Endorsement Factor Analysis* Internal†
Frequency I II Consistency
Sociable 91% .07 .69 .57
Bright 90% .06 .66 .54
Lively 89% -.23 .80 .78
Cheerful 89% -.20 .72 .67
Self-Confident 88% -.24 .79 .76
Hard-working 88% -.23 .75 .72
Relaxed 88% -.22 .69 .66
Enterprising 86% -.17 .79 .75
Dynamic 84% -.25 .72 .70
Active 81% -.34 .60 .59
Table 2 INTERCORRELATION MATRIX AND FACTOR ANALYSIS OF THE GMS, POMS, STAI, HPPQ AND MC SCALES (N=445).
Intercorrelation Matrix *
2. 3. 4. 5. 6.
GMS 1. Negative Affect -.39 .92 .63 .58 .41
2. Positive Affect - -.36 -.36 -.30 -.19
POMS 3. Fatigue - .63 .55 .40
4. Depression - .75 .61 -.31
5. Tension - .69
6. Anger -
STAI 8. Transient Distress
HPPQ 9. Well-Being
MC 10. Self-Deception
GMS denotes Global Mood Scale; POMS: Profile of Mood States (Dutch adaptation); STAI: State-Trait Anxiety Inventory; HPPQ: Heart Patients
Psychological Questionnaire; MC: Marlowe-Crowne scale.
* Correlations >.16: p<.001, correlations >.10: p<.01.
Factor Analysis †
7. 8. 9. 10. Factor I Factor II Factor III
-.35 .46 -.60 -.11 .85 -.27 .16
.89 -.49 .46 .12 -.21 .93 .08
-.35 .43 -.55 -.09 .84 -.25 .20
.60 -.57 -.15 .83 -.16 -.19
-.24 .68 -.60 -.17 .82 -.08 -.32
-.14 .49 -.43 -.26 .67
- -.44 .43 .10 -.16 .94 .04
- -.66 -.25 .58
- .23 -.64 .41 .25
- .03 .09 .82
eigenvalues= 5.11 1.49 1.09
† Principal components with varimax rotation; loadings≥.40 are underlined; loading of scales assigned to a factor are presented in boldface.
Table 3 DESCRIPTIVE CHARACTERISTICS OF THE NEGATIVE AFFECT AND POSITIVE AFFECT SUBSCALES OF THE GMS (N=478).
Mean Median Interpretation of Raw Scores
Low Rather Low Intermediate Rather High High
Negative Affect 9.5 (8.7) 7 0 - 1 2 - 4 5 - 9 10 - 15 16 - 40
Positive Affect 19.4 (8.3) 20 0 - 11 12 - 17 18 - 20 21 - 25 26 - 40
Standard deviations appear in parentheses; GMS denotes Global Mood Scale.
Table 4 MEAN ENTRY AND END NEGATIVE AFFECT AND POSITIVE AFFECT GMS SCORES FOR REHABILITATION AND CONTROL SUBJECTS
Entry Score End Score Change F
Rehabilitation 8.9 (8.3) 5.4 (7.1) - 3.5 15.64, p<.0001
Control 8.6 (7.8) 8.0 (8.0) - 0.6 0.51, p=.48
Standard deviations appear in parentheses; GMS denotes Global Mood Scale; entry score: mean score within six weeks after the coronary event;
end score: mean score three months after the initial assessment; F: repeated measures analysis of variance (dfs=1,59).
Entry Score End Score Change F
19.5 (7.4) 24.2 (6.7) + 4.7 24.57, p<.0001
17.6 (8.1) 19.0 (7.0) + 1.4 2.29, p=.14
Scree plot showing the eigenvalues of the first 10 principal factors that were identified in the list of
20 mood terms comprising the GMS.
LEGEND TO FIGURE 1
Dr. M. Fisher,
Editor Psychological Medicine
Institute of Psychiatry
De Crespigny Park,
Denmark Hill, London SE5 8AF
Dear Dr. Fisher,
Re: "Emotional distress and fatigue in coronary heart disease: The Global Mood Scale (GMS)"
I wish to thank you for your letter of 27 May enclosing reviewers comments on the above
manuscript. I do appreciate that you would be willing to consider the present paper for publication
in Psychological Medicine. I am indebted to the anonymous reviewers for their constructive
comments and I am convinced that the manuscript is now improved by the revision you
I am in agreement with most of the comments of the reviewers and therefore have corrected the
paper in a fashion that deals with the various issues raised by them. My responses to these
comments are detailed in the attached sheets.
I hope that this revision of my manuscript meets the various points raised by your referees and that
you therefore would be willing to consider this study for publication in Psychological Medicine.
Please find enclosed 4 copies of the revised manuscript.
Address for correspondence :
UZA - Cardiale Revalidatie
BELGIUM Telephone: 00 32-3-829.11.11 (ext. 1941) Fax: 00 32-3-829.05.20
19 June 1992
Responses to Comments of Reviewer # 1.
Your point regarding the fact that patients with non-cardiac disorder experience fatigue on exercise
is well taken. I agree that the statement that "as a rule, fatigue due to CHD is related to effort,
whereas fatigue related to emotional distress is constantly present" can be questioned. Therefore,
this statement is now deleted (page 3, 4th paragraph).
Page 3, 2th paragraph, first line: the word 'unspecific' is now deleted and replaced by 'non-specific'.
Responses to Comments of Reviewer # 2.
1. Reference to Kroenke et al. 1988 is deleted, and reference is now made to the population based
survey of Chen (1986) on page 3, 4th paragraph, lines 2-6: "in the general population, fatigue is
highly associated with emotional distress, and adults who experience any psychological problems
are at much higher risk of feeling fatigue than those who are free from psychological problems"
2. The reference following the statement that "cardiac patients are not psychiatric patients" on page
4, 2th paragraph, first line, is deleted.
3. The Method section now includes a paragraph which describes the cardiac rehabilitation program
somewhat more in detail (page 4, last paragraph). The selection of the subject sample is now
described in the last two paragraphs of page 4.
4. I rather suspect that, in the context of cardiac rehabilitation, the Marlowe-Crowne scale is not a
social desirability measure but instead is a measure of an individual difference variable which is
related to defensiveness and social adjustment. This is now stated in the Method section (page 5,
last paragraph), and the work of Gur & Sackeim (1979), Lane et al. (1990), and McCrae & Costa
(1983) are cited because these studies provide evidence for the latter contention.
5. The extraction of two factors is now discussed more in detail in the Results section, page 6, last
paragraph. I agree that the number of factors to retain in a factor solution is an important issue;
nonetheless, the present findings are in complete agreement with the Watson & Tellegen (1985)
paper which describes positive and negative affect as two dominant dimensions of emotional
6. Page 11, lines 6-8: it is now stated that "feelings of exhaustion (Appels & Mulder, 1988) and
depression (Booth-Kewley & Friedman, 1987) may be associated with the development of CHD"
7. The exact P values are now incorporated in the 5th and 9th columns of Table 4, page 22.
Responses to Comments of Reviewer # 3.
1. I agree that the final sentence of the third paragraph on page 3 was hard to understand. In fact,
this sentence referred to (1) the distribution of positive and negative affect scores between
individuals, as well as (2) the change in negative affect scores for one individual over time. This is
now more clearly stated on page 3, 3th paragraph, lines 7-11. Reference has now also been made to
the work of Zevon & Tellegen (1982) to further document both contentions.
2. Mention has now been made to the fact that "since all subjects were native speakers of Dutch ( ...
), this language was used to assess subjective mood states" , page 5, second paragraph, lines 1-3.
The fact that the GMS given in the appendix is an English translation of the questionnaire used is
now clearly stated in the last sentence of this paragraph.
3. Page 4, 3th paragraph, line 4: "about 100 kilometers from Antwerp".
4. The Methods section now includes references to Mardia et al. (1979) and Cattell (1966) in the
description of multivariate analysis and use of the scree plot (page 6, 4th paragraph, lines 2 and 5,
5. Mention is now made to the total variance explained by the 3th, 4th, and 5th factor, respectively.
Mood terms that loaded on these factors also displayed, however, substantial loading on one of the
first two factors. The extraction of factors is discussed more in detail on page 6, last paragraph, lines
6. Page 7, last paragraph, line 7. The statement that "negative affect scores tend to remain at a
constant low level" is now deleted and is replaced by the statement that "intense negative mood
terms occur infrequently in normal subject (Clark & Watson, 1991)".
Dr. Penny McLaughlan, Download full-text
Technical Editor Psychological Medicine
1 Exeter Close,
Cambridge CB2 2NG
Dear Dr. McLaughlan,
Please find enclosed a signed copyright form concerning my paper 'Emotional distress and
fatigue in coronary heart disease: the Global Mood Scale (GMS)'.
In response to the additional questions that you posed in your letter, I hereby send you the
1. Cattell (1966). This reference may be replaced by the following reference:
Cattell, R.B. (1966). The scree test for the number of factors. Multivariate Behavioral Research,
2. Denollet (1992). This paper has been accepted for publication. There are no more details
UZA - Cardiale Revalidatie
28 September 1992.