Positive affect as a factor of resilience in the pain—negative affect relationship in patients with rheumatoid arthritis
The purpose of this study is to examine positive affect (PA) as a factor of resilience in the relationships between pain and negative affect (NA) in a sample of patients with rheumatoid arthritis. Forty-three patients (30 women; mean age, 57 years) were interviewed weekly by telephone for 8 weeks. Multilevel modeling was applied to study the within-week relationships among the variables. There was a Pain x PA interaction effect on NA (beta=-0.05, P<.01) indicating a weaker relationship between pain and NA in weeks with more PA. Pain (beta=0.37, P<.002), interpersonal stress (beta=2.42, P<.001), depression (beta=0.26, P<.01), average perceived stress (beta=10.80, P<.001), and also weekly PA (beta=-0.1, P<.01) had a main effect upon NA. Positive affect is most influential in reducing NA during weeks of higher pain and may be a factor of resilience, helping patients experiencing pain fluctuations as less distressful than at lower levels of PA.
Positive affect as a factor of resilience in the pain—negative affect
relationship in patients with rheumatoid arthritis
Elin B. Strand
, Alex J. Zautra
, Magne Thoresen
, Sigrid adeg3rd
, Arnstein Finset
Department of Behavioural Sciences and Statistics, Institute of Basic Medical Science, University of Oslo, POB 1111 Blindern, N-0317 Oslo, Norway
Department of Psychology, Arizona State University, Tempe, AZ, USA
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
Received 2 May 2005; received in revised form 8 August 2005; accepted 16 August 2005
Objective: The purpose of this study is to examine positive
affect (PA) as a factor of resilience in the relationships between
pain and negative affect (NA) in a sample of patients with
rheumatoid arthritis. Methods: Forty-three patients (30 women;
mean age, 57 years) were interviewed weekly by telephone
for 8 weeks. Multilevel modeling was applied to study the
within-week relationships among the variables. Results: There
was a Pain
PA interaction effect on NA (b=0.05, Pb.01)
indicating a weaker relationship between pain and NA in weeks
with more PA. Pain (b=0.37, Pb.002), interpersonal stress
(b=2.42, Pb.001), depression (b=0.26, Pb.01), average per-
ceived stress (b=10.80, Pb.001), and also weekly PA (b=0.1,
Pb.01) had a main effect upon NA. Conclusion: Positive af-
fect is most influential in reducing NA during weeks of higher
pain and may be a factor of resilience, helping patients experienc-
ing pain fluctuations as less distressful than at lower levels
D 2006 Elsevier Inc. All rights reserved.
Keywords: Negative affect; Pain; Positive affect; Resilience; Rheumatoid arthritis; Stress
In this paper, we ask whether the stressful impact of
chronic pain is lessened by the presence of positive
emotions for patients with rheumatoid arthritis (RA).
Chronic pain is reported as the most widespread and
challenging symptom for patients with RA  and a high
priority for physician’s attention . Pain in RA is also a
potential stressor not only because it is a highly aversive
bodily experience but also because the pain intensity and
duration fluctuate in a relatively unpredictable and uncon-
Pain varies between individuals and across situations in
intensity and duration, and patients differ in the extent that
arthritis pain gives rise to emotional distress. Although there
is a well-established association between pain and negative
affect (NA) [3,4], both interpersonal stress and also
depression play a role in a patient’s vulnerability to pain
[5–11]. For RA patients, negative affective responses to pain
may influence illness course, increasing the freque ncy of
painful flares, lowering pain thresholds, intensifying pain
behaviors, and deteriorating coping [12–19]. Thus, identi-
fying factors that may diminish the established connection
between pain and NA may be of considerable value to the
health as well as the mental health of RA patients.
A shift in focus in pain research to explore an RA patient’s
capacities for resilience as well as their vulnerabilities to pain
appears warranted at this juncture. The concept of resilience
refers to the person’s ability to bounce back from negative
emotional experiences and show a flexible adaptation to the
changing demands of stressful experiences .These
attributes are of considerab le importance for sustaining
health and well being [21,22]. Positive emotions may be
0022-3999/06/$ – see front matter D 2006 Elsevier Inc. All rights reserved.
T Corresponding author. Department of Behavioural Sciences and
Statistics, Institute of Basic Medical Science, University of Oslo, POB 1111
Blindern, N-0317 Oslo, Norway. Tel.: +47 22 85 10 21; fax: +47 22 85 13 00.
E-mail address: firstname.lastname@example.org (E.B. Strand).
Journal of Psychosomatic Research 60 (2006) 477–484
essential factors in the process of resilience following adverse
events [23–27], including adverse experiences wi th chronic
pain . Tugade and Fredrickson  found that high-
resilient individuals tended to report positive emotions even
when under stress, and that these positive emotions con-
tributed to recovery from stress-related negative effects. Their
bBroaden and BuildQ theory of positive emotions  posit s
that persons with higher positive affect (PA) have greater
capacity to recover psychologically and physiologically to
stressful events. Positive emotions may expand the range of
cognitions and behaviors to build an individual’s physical,
intellectual, and social resources [29–31].
The role of PA in persons with chronic pain has been
examined by Zautra et al. [28,32]. In their dynamic model of
affect (DMA), they suggest that the relationship between PA
and NA changes as a function of context [33–35]. Dynamic
model of affect posits that stressful events change the degree
of independence between the affective states so they become
less differentiated, that is, more bipolar. Thus, according to
the DMA, people who can sustain higher levels of PA at the
time of the stressor would show significantly less NA .
In one longitudinal study of arthritis (RA) patients, they
found that the presence of positive affective states reduced
the size of the relationship between the patient’s reported
weekly baverage painQ and NA . Weekly registrations of
pain and affect were employed for a period of 12 to
20 weeks. In this study, they examined the role of PA in the
relationship between pain and NA, and with mood clarity as
a confounder. So far, no study other than Zautra et al’s 
has explored this relationship with a combined within- and
between-person design, and advanced statistical methods
such as multilevel modeling.
Stress is highly related to the environmental context—
especially interpersonal events . For patients with RA,
stress in interpersonal relationship is associated to increased
disease activity, depression, and pain [8,17]. In this group of
patients, the PA–interpersonal stress interaction on NA has
not, as far as we know, been examined. In the current study,
we also explore interpersonal stress, that is, the patient’s
perceived stress in friends, family, and s pouse/partner
The current study is a replication of Zautra et al’s study
 only in so far as it tests the relationships among pain,
PA, and NA. We have also added tests of the role of
interpersonal stress, which was not included in the prior
study. We also studied bworst painQ during the past week,
which was another departure from prior research that relied
on reports of last week’s average pain. The bipolarity of the
affects and the resilience factor are both stress-related
phenomenon. Bipolarity in affects is according to DMA, a
consequence of stressful events. For resilience to display,
there n eed to be aversive stat es to bounce back from, and
because the worst pain more closely identifies a stressful
event, we rely on this pain rating in our study.
To date, the role of PA as a source of resilience has not
been studied in patients with RA. This study aims to bridge
that gap and expand our understanding of the affect
interrelationships in RA.
Norms for experiencing and expressing emotions differ
widely between countries, even between countries that on
most dimensions may appear similar and share many
sociocultural features , such as Norway and the United
States. It is therefore valuable to test the effects of PA on NA
among RA patients who reside in these countries other than
the United States.
In this paper, we examine data on a sample of Norwegian
patients with RA on the association between pain fluctua-
tions, elevations in interpersonal stress, and NAs. We also
address the question of how PA influences these relation-
ships. Finally, we explore individual differences in depres-
sion and perceived interpersonal stress as vulnerability
factors in the experiences of NA during chronic pain.
The sample consisted of 43 patients with RA included
in a 10-year follow-up of the Norwegian EURIDISS
cohort (European Research in Incapacitating Diseases and
Social Support ). At entry into the cohort 10 years
prior, patients had been diagnosed with RA within the
last 4 years. They were asked to take part in the current
study when they came to the hospital for the 10-year
follow-up examination. Of the 238 patients originally
included in the EURIDISS study at T1 (1992), 35 patients
had died. Forty-two individuals refused to take part in the
follow-up, and 12 patients did not take part in the
follow-up for other reasons (could not be located, had
moved, etc.). Thus, 149 (63% of 238) patients took part
in the 10-year follow-up.
Of these 149 patients, 43 participated in the current
study. The present sample consisted of 30 (70%) wom an
and 13 (30%) men. The mean age was 57.5 (S.D.=13.1)
with a range from 33 to 80 years. Of the 43 patients,
26 (60%) were married or living with a partner, 33 (75%)
had one or more children, and 10 (23%) were in a full-time
job, 5 (12%) had a part-time job, and the rest [28 (65%)]
were on age or disability pension. A comparison of this
sample to the EURIDISS cohort on age, education, sex,
Steinbrocker (physical function), Physician global clinical
evaluation (VAS), SF-36, Nottingham Health Profile, HAQ,
and GHQ revealed significant differences only in age and
education. The current sample was younger and had longer
education than the EURIDISS cohort.
Overall, the current sample was functioning at a relatively
high level for RA patients. Of the 43 patients, 80% had a
Steinbrocker score (a global measure of function) of 2 on a
scale ranging from 1, which is no impairmen t, to 4, which
signifies extensive handicap such as using a wheelchair or
staying in bed. None of the RA patients had a score on IV.
E.B. Strand et al. / Journal of Psychosomatic Research 60 (2006) 477 –484478
The patients wer e invited to the hospital for an initial
interview. They were given the first standardized interview
and asked to complete baseline questionnaires. The
participants were then given weekly, standardized telephone
interviews during an 8-week period. In these interviews,
they were asked to give a report about last week’s pain, PA,
NA, as well as interpersonal stress. A total of 336 weeks of
data were obtained, with only 8 weeks of missing data, for a
98.5% completion rate. The missing weeks were distributed
on eight different persons: five women and three men. Two
of the missing weeks were in the person’s interview week
number 3, one in the interview week number 5, another in
the interview week number 7, and the other three in the
interview week number 8. Two of the missing weeks were
due to the interviewer himself, another two were due to
hospital stay, forgetting (two), exhaustion (one), and death
in the family (one). Most of these missing weeks are to be
considered random missing. The proportion of missing
weeks is small, and even smaller are the missing weeks due
to worsening of health or illness fluctuations (n=3). No one
of the patients mentioned pain, PA, NA, interpersonal
stress, or depression, all important variables in the study,
as reasons for not being able to undertake the telephone
interview. Based on this analysis, we do not consider
neither the number nor the reasons for the missing data to
be of any serious threat to the integrity of the data ana-
During the phone interview, the participants were asked
to rate last week’s pain due to their RA on an 11-point
numeric rating scale with points from 0 (no pain) to
10 (worst possible p ain) . They separately rated three
aspects of the pain: the most intense, the least intense, and
the average pain level, over the past week. We provide data
on each of the three pain ratings but rely on the rating of
most intense pain (MIP) in the test of the effects of PA
because this measure most closely identifies weeks when
the person’s pain is the most stressful. Research also has
shown that peak intensity of pain is less likely to be biased
by retrospective recall .
Positive affect and negative affect
To measure affect weekly, we used Positive and
Negative Affect Schedule, which is an established instru-
ment developed to tap the two major dimensions of mood—
positive and negative affectivity . One of the distin-
guishing aspects of the scale’s development was its
emphasis on indices of PA and NA that were indepe ndent.
We used Watson et al.’s own categorizing for PA and NA
with 10 items in each affect category. Participants were
asked to indicate on a five-point scale, bto what extent did
you experience each of the adjectives for positive and for
NA during the previous week.Q The five-point scale is
labeled 1, very slightly/not at all; 2, a little; 3, moderately;
4, quite a bit; and 5, very much. The adjectives for PA were
bproud,Qbalert,Qblively,Qbactive,Q and bdetermined,Q and for
NA, the adjectives were bdistressed,Qbupset,Qbnervous,Q
and bguilty.Q PANAS was translated from English into
Norwegian and then translated back into Norwegian by a
person with English as first language. After discussions
among authors on divergences between the versions, the
final solutions were used in the study. The trans lations of
PANAS were executed specific for this study, and therefore,
there are no other validation of the instruments to compare
with. Watson et al.  assert that internal consistencies for
both scales have been ranging from .86 to .90 for PA and
from .84 to .87 for NA in their studies. In the current study,
the Cronbach’s a was .90 for NA and .83 for PA. In Watson
et al’s studies, the correlation between the NA and PA
scales has been invariably low, ranging from .12 to .23.
In our study, th e correlation between NA and PA
was .11 for the weekly scores and .25 for the average
The patients were asked to indicate on a four-point scale
the extent interpersonal stress arising over the past week in
each of the follow ing areas: friends, family, and spouse/
partner. bOverall, how stressful wer e your relations with
friends (family, partner) this past weekQ (zero=not stressful
at all, 1=a little stressful, 2=moderately stressful, and
3=extremely stressed). Each of these questions followed
probes regarding number of stressful events in eac h of the
three life domains taken from the Inventory of Small Life
Two interpersonal stress variables were computed. An
average interpersonal stress variable across the 8 weeks
was computed for each participant based on the mean of
three weekly ratings: perceived stress with friends, family,
and spouse/partner (if present). Another weekly inter-
personal stress score was calculated by subtracting each
individual’s weekly score from his/her average score. This
person-centered method of creating the weekly deviation
scores was also used for all the weekly variables used in
Beck Depression Inventory (BDI) was given at the initial
interview. Beck Depression Inventory is a wi dely used
instrument to measure depression and consists of 21 items
that assess cognitive–affective and vegetative signs of
depression. The BDI has been used widely to assess depressive
symptoms in psychiatric and nonpsychiatric populations .
E.B. Strand et al. / Journal of Psychosomatic Research 60 (2006) 477 –484 479
We wanted to investig ate the relationship between NA
and pain, PA, interpersonal stress (IS), and depression,
measured at eight weekly time points, adjusting for
individual characteristics of the patients. The assess-
ments provided two levels of data: level 1 consisted of the
variables that varie d within participants across weeks; level
2 variables identified individual differences that varied bet-
ween participants but not over weeks. We analyzed the
multilevel model with SAS PROC MIXED software (e.g.,
Ref. ). For the level 1 data (the relationship among
the variables measured weekly), the equation may be stated
IS þ c
where the subscripts i and j represent week number and
patient number, respectively.
The variable bweek1Q indicates whether the measurement
is made in the first week or not, and inclusion of this
variable controls for elevations in level commonly found at
the first weekly measurement compared with subsequent
weekly assessments. The independent variables weekly
MIP, weekly PA, and weekly IS are centered at the mean
value for each person. These centered variables identify
weekly fluctuations in level of pain, PA, and interpersonal
stress, independent of the person’s average level across the
8 weeks. To test how PA modulates the relationships
between pain, interpersonal stress, and NA, we included
interaction terms shown in the equation.
The level 2 equatio n mod els the between-subject
variation in level 1 intercepts:
This level of analysis is used to explore the extent to
which NA was affected by individual differences in
depression, average perceived interpersonal stress (AvgIS),
average PA (AvgPA), and average MIP (AvgMIP). In
addition, separate equations for the interactions between
levels 2 and 1 examined individual differences in PA on the
Means, S.D., and correlation coefficients of predictor variables in the multilevel analyses
Variable n Mean S.D. Range NA MIP PA IS
NA (raw score) 333 13.8 4.67 23
Within-person deviation scores
Weekly MIP 336 0.00 1.52 11.3 0.12T
Weekly PA 328 0.00 4.46 34.0 0.11 0.06
Weekly IS 333 0.00 0.27 2.31 0.15TT 0.004 0.04
Average MIP 43 4.75 2.32 9.50 0.16
Average PA 43 31.00 6.00 31.5 0.25 0.37T
Average IS 43 0.22 0.23 0.88 0.52TT 0.41TT 0.08
Depression 41 8.34 4.20 20.0 0.32T 0.06 0.35T 0.10
n refers to the number of observations. The scores on the weekly variables are centered by subtracting the observed score from each person’s average across the
eight weekly observations.
T Pb.05 level (two tailed).
TT Pb.01 (two tailed).
Fig. 1. Interaction of PA on weekly MIP on NA.
E.B. Strand et al. / Journal of Psychosomatic Research 60 (2006) 477 –484480
weekly pain–weekly NA and on the weekly IS–weekly NA
relationships (the last one not shown):
BDI þ c
AvgIS þ c
AvgMIP þ u
In the final model, only the intercept (g
) was allowed to
vary among patients and was modeled as a random effect.
Because of the relativel y small number of subjects, we
decided not to attempt to estimate random effects of the
variables in the model. Further, we modeled the dependence
between repeated measurements of NA within patients as an
autoregressive process of order 1. The dependent variable
looked somewhat skewed. One important assumption
behind linear multilevel model is that the residuals are
normally distributed [41,42]. The estimated residuals for
normality were examined and found satisfactory.
Initial analyses provi ded descriptive statistics and corre-
lations among study variables. Means, S.D.s, and correla-
tions between NA and the predictor variables are shown
in Table 1.
Negative affect was correlated with weekly MIP (r=.12,
Pb.05) and IS (r=.15, Pb.01), but not with PA. Negative
affect was, correlated with between-person differences in IS
(r=.52, Pb.01), and depression (r=.32, Pb.01), and not with
PA. Among the between-person variables, there was a
moderate negative correlation between PA and MIP
(r=.37, Pb.05), and MIP was also associated with more
interpersonal stress (r=.41, Pb.01). T here was also a
moderate negative correlation between PA and depression
(r=.35, Pb.05). There was no correlation between MIP and
depression, average PA and average IS, and IS and
depression. These last set of correlations show that our
assessments of PA, pain and stress yielded i ndividual
differences on key variables that were distinct from depres-
sion and also different from one another.
To analyze the effects of weekly MIP, weekly PA, weekly
IS, and individual differences in depres sion and inter-
personal perceived stress on NA, we used multilevel
modeling as outlined earlier.
On level 1, weekly MIP had a strong effect upon NA
(b=0.37, Pb.0002). On weeks with more pain, NA was sig-
nificantly higher. This effect was moderated, however, by
weekly PA. Weeks of a higher PA moderated the effect of
pain on NA. This relationship is illustrated in Fig. 1. Further,
there was a significant effect of weekly PA on NA (Table 2).
Weekly interpersonal stress was also associated with NA
(b=2.42, Pb.0001), but there was no interaction effect
between PA and IS in influencing NA. We also executed the
same analyses for both weekly average pain and weekly
lowest pain level. The same significant result on NA were
found for these pain variables as with the MIP level except
from the interaction with PA, which was nonsignificant for
both the average and lowest pain level.
When examining level 2 variables for between-person
effects, we found that individual differences, both the
average inte rpersonal stress (b=10.80, Pb.0001) as well as
depression (b=0.26, Pb.017), significantly increased NA.
In the final model, we included only those variables that
were significant. This model (illustrated in Fig. 2) can be
formulated as a so-called mixed model:
week1 þ u
where the random effect u
reflects the between-person
variability in the intercept.
Multilevel regression predicting weekly NA
estimated Subject b S.E. ZP
Un (1,1) ID 4.52 1.56 2.89 .001
Ar (1) ID 0.23 0.09 2.60 .009
Residuals ID 8.57 0.95 8.98 .0001
Predictor variables b S.E. tP
Level 1 within-person variables
Weekly IS 2.42 0.58 4.17 b.0001
Weekly MIP 0.37 0.12 3.19 .002
Weekly PA 0.103 0.04 2.88 .004
Week1 1.97 0.49 3.98 b.0001
Weekly PAT Weekly MIP 0.05 0.02 2.37 .019
Level 2 between-person variables
Average PA 0.11 0.08 1.40 .172
Average MIP 0.02 0.22 0.11 .917
Average IS 10.80 1.93 5.61 b.0001
Depression 0.26 0.10 2.52 .017
For the level 1 analyses, we only report the significant results. n=336
weekly measurements for within-person analyses and n=43 for between-
Fig. 2. Final model of associations based on multiple regression analyses.
E.B. Strand et al. / Journal of Psychosomatic Research 60 (2006) 477 –484 481
In this study, we found a significant association between
weekly pain, weekly stress, and weekly NA. Moreover, we
found a weekly Pain
PA interaction effect, indicating that
PA moderated the effects of pain on NA such that higher
levels of PA reduced NA during weeks of high pain. Weekly
PA also had a direct effect on NA in significantly reducing
it. Depression and average perceived stress across weeks
were also associated with weekly NA and served as
vulnerability factors in relation to NA.
Weekly PA did not influence the IS–NA relationship.
The average level of PA across the 8 weeks was unrelated to
NA directly and also did not influence neither the effects of
pain nor the effects of interpersonal stress on NA.
Our findings are similar to those of Zautra et al.  in
their study of a sample of RA and osteoarthritis patients in
the United States. In both studies, weekly PA (bstateQ), but
not mean PA across weeks (btraitQ), was inversely related to
weekly NA, and PA seemed to reduce the effect of pain on
NA in weeks of higher pain. Bot h individual differences in
IS, MIP, and depression were in the current sample
correlated to NA, where IS had the strongest correlation.
In the regression analyses, both average IS and depression
were significantly associated to NA, whereas average MIP
was not. In the United States study, individual differences in
pain across weeks explained a significant proportion of the
variance in weekly NA. In the main model of our study
(Table 2), between-subject differences in pain across weeks
were unrelated to NA. In contrast to the United States study,
this study included interpersonal stress in the model. If
interpersonal stress was removed from the equation, pain
across weeks made a significant contribution to NA similar
to what Zautra et al.  found. Our findings indicate that
both weekly pain and weekly interpersonal stress function
as sources of NA, whereas the stable aspect of pain as a
stressor (at least in our sample) covaried with interpersonal
stress, as a strong predictor of NA. In the United State s
study, the authors used the patients’ average pain as pain
measurement; the Norwegian study used the bMIP.Q The
pain level seems to be somewhat lower in the present study
(MIP, 4.7, and average pain level, 3.5, on a scale from 0 to
10) than in the United States samples (for RA patients,
average pain level was 43 on a scale from 0 to 100); still, we
found the same effect of PA on the pain–NA relationship.
The differences between the studies appear best explained
by the measures of pain used than by cultural differences,
although we do not have data that h ave a direct bearing on
Our findings on the pain–affect relationship are in
accorda nce with the DMA postulatin g a more bipolar
relationship between PA and NA during the stress of
increased pain fluctuations. In our data, higher average PA
did not protect the RA participants from NA associated with
weekly pain. Positive affect was most important as a
deterrent when pain was at its worst. Thus, the state
dimension of PA may be thought of as a source of resilience
during aversive states like with increasing pain. The resilient
effect of PA in the pain–NA relation may result from the rise
in the person’s well-being, and also through shifts in their
cognitive ap praisals of self-efficacy and other reframin g of
the pain and their own coping efforts. More research is
needed to identify the mechanisms by which PA is
protective during painful episo des. Of interest in particular
is the extent to which this influence of PA is due to a
narrowing of affective differentiation as proposed by Zautra
 and/or a boost in affective resources as proposed by
Rheumatoid arthritis participants with more depression
and interpersonally stressed overall reported more NA, and
also, weeks of high IS were associated with elevations in
NA. These findings are in consistence with lots of the
research initially mentioned. However, weekly PA did not
influence the interaction between weekly interpersonal
stress and NA as expected from the DMA. This negative
finding may be due to a small sample and a rather low level
of reported stress, which means that the stress-related NA is
not strong enough to provoke bipolar affective functioning.
If this is the case, then the nonsignificant results on the
stress–PA interaction here are not inconsistent with the
DMA model that we tested. These results may also indicate
that stress and NA are two aspects of the same phenomena
employed in two different ways through affect rating and
questions about perceived stress. The results imply that they
may be linked in such a way that not even an elevation in
PA can separate them. That PA interacts differently in the
pain–NA than in the stress–NA relationship may also
indicate that pain and stress are two very different sources
of NA and, the refore, d emand different sources for
bhealing,Q that is, PA may be a better source of resilience
interpersonal stress. This is quite speculative, and the two
sources of NA such as pain and interpersonal stress should
be further explored.
Both PA and NA mean scores in the present study are
similar to those seen in other samples both clinical and
nonclinical, using PANAS as affect measures [32,43,4 4].
Whether o ur results on the affect relationships woul d
generalize to other populations of chronically ill awaits
The patients in our study were recruited from a lager
sample of RA patient, and one-third took part in our
study. Nonparticipation may be due to several reasons.
Given the difference in age and education between the
total and our samp le, we presume that when presented our
follow-up study, it seemed too demanding to the oldest
and those with the lowest education. In summary, the
sample that completed our study compares favorably with
the larger sample from which they were drawn, which
E.B. Strand et al. / Journal of Psychosomatic Research 60 (2006) 477 –484482
gives us some confidence that the group is not overly
biased in health and/or well-being. Our sample may still
be more resilient than a random sample of the RA
patients. It is noteworthy, however, that they did report
fairly substantial levels of joint pain in our study and
levels of disability comparable to the larger cohort from
which they were drawn.
We used a once-a-week measurement often used in
research, and by consequence, the information is given
retrospectively. Studies comparing patient’s evaluations of
both momentary and recalled pain have shown that
patients accurately recalled the severity of a pain episode
for at least 1 week  and tended to recall the peak level
and the most recent level [46,47]. Thus, the MIP level as
used in our study appears to be relatively free of recall
bias; nevertheless, some caution within interpretation of
the finding is called for given the 7-day time span bet-
The affective state at the time of a painful experience
may shape the nature of the experiences and what is later
recalled . For example, NA at recall, may influence an
individual’s report of the prior week’s pain and interpersonal
stress. For example, depressed persons recall more pain than
those who are not in such a mood [49,50]. Still, an
important quest ion left unresolved is whether the findings
that infer same-time associations refer to influences over the
full week, or are best thought of as associations within a
shorter time span than that which was measured. The DMA
model that was tested makes no assumptions regarding the
proper length of time that a same-time association may be
observed. Further studies are needed to gauge the time
interval within which changes in the nature of the relation-
ships among affective states are most likely to occur. The
weekly variables involved in the study ma y fluctuate
frequently; both pain and affect may change several times
during a week and even within 1 day. Daily and even
within-day assessments are to be encouraged in future
studies of this kind to rule out potential effects of biases in
The main finding from our study is that PA appears to be
an important resilience factor protecting patients with RA
during pain fluctuations. This potential of the positive
affective resources may encoura ge new approaches to
improving the quality of life of patients with chronic pain.
Interesting questions remain regarding the differences
between persons in their capacity to mobilize and experi-
ence positive emotional states when pain increases, and to
what degree the person’s social life and interpersonal
relations influence in this process. In our analyses, we
controlled for individual d ifferences in depression and
interpersonal stress to rule out potential confounds to NA
and PA. Findings from this study invite further exploration
of how differences in individual capacities in emotional
awareness and regulation, and the person’s social resources
and interpersonal relations influence adaptation to chronic
pain conditions such as RA.
This research was funded by the Research Council of
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