Content uploaded by Felicity L Bishop
Author content
All content in this area was uploaded by Felicity L Bishop on Mar 07, 2015
Content may be subject to copyright.
Available via license: CC BY-NC-ND 3.0
Content may be subject to copyright.
Psychological Covariates of Longitudinal Changes in
Back-related Disability in Patients Undergoing Acupuncture
Felicity L. Bishop, PhD,*Lucy Yardley, PhD,*Philip Prescott, PhD,
w
Cyrus Cooper, MA, DM, FRCP, FMedSci,
z
Paul Little, MD, PhD, FRCGP,
y
and George T. Lewith, MA, MD, FRCP, MRCGP
y
Objectives: To identify psychological covariates of longitudinal
changes in back-related disability in patients undergoing
acupuncture.
Materials and Methods: A longitudinal postal questionnaire study
was conducted with data collection at baseline (pretreatment), 2
weeks, 3, and 6 months later. A total of 485 patients were recruited
from 83 acupuncturists before commencing acupuncture for back
pain. Questionnaires measured variables from 4 theories (fear-
avoidance model, common-sense model, expectancy theory, social-
cognitive theory), clinical and sociodemographic characteristics,
and disability. Longitudinal multilevel models were constructed
with disability over time as the outcome.
Results: Within individuals, reductions in disability (compared with
the person’s individual mean) were associated with reductions in:
fear-avoidance beliefs about physical activity (b= 0.11, P< 0.01)
and work (b= 0.03, P< 0.05), catastrophizing (b= 0.28,
P< 0.05), consequences (b= 0.28, P< 0.01), concerns (b= 0.17,
P< 0.05), emotions (b= 0.16, P< 0.05), and pain identity
(b= 0.43, P< 0.01). Within-person reductions in disability were
associated with increases in: personal control (b=0.17,
P< 0.01), comprehension (b=0.11, P< 0.05) and self-efficacy
for coping (b=0.04, P< 0.01). Between individuals, people who
were less disabled had weaker fear-avoidance beliefs about physical
activity (b= 0.12, P< 0.01), had more self-efficacy for coping
(b=0.07, P< 0.01), perceived less severe consequences of back
pain (b= 0.87, P< 0.01), had more positive outcome expectancies
(b=0.30, P< 0.05), and appraised acupuncture appointments
as less convenient (b= 0.92, P< 0.05).
Discussion: Illness perceptions and, to a lesser extent, self-efficacy
and expectancies can usefully supplement variables from the fear-
avoidance model in theorizing pain-related disability. Positive
changes in patients’ beliefs about back pain might underpin the
large nonspecific effects of acupuncture seen in trials and could be
targeted clinically.
Key Words: acupuncture, back pain, fear of pain, health knowl-
edge, attitudes, practice, self-efficacy
(Clin J Pain 2015;31:254–264)
Personally, economically, and socially, back pain is
costly.1Acupuncture is recommended by UK clinical
guidelines for low back pain (LBP)2and is commonly used
for LBP.3In randomized clinical trials acupuncture has
shown large effects on chronic pain compared with usual
care or waiting list controls but often only small effects
compared with sham acupuncture.4,5 This suggests acu-
puncture has large nonspecific effects, that is, factors other
than needling characteristics contribute to patients’ out-
comes.6Indeed, acupuncture can be conceptualized as a
complex intervention in which changes in patients’ health
are produced not only by needling but also by more psy-
chosocial factors such as empathic therapeutic relationships
and holistic consultations in which discussions of lifestyle
and self-care can trigger changes in how patients think and
feel about their symptoms and their ability to manage
them.7–10 However, little is known about the psychosocial
factors and processes that might be involved in acupuncture
for LBP: established psychological models have not been
applied to understand acupuncture’s effects. Although
variables from such models may not be explicitly addressed
by acupuncturists, this does not mean they are not involved
in patients’ ongoing LBP in this treatment context. There-
fore, a comprehensive and theoretically informed inves-
tigation of psychological covariates of acupuncture’s effects
on LBP was designed, drawing on major theoretical
frameworks that have predicted LBP outcomes in patients
undergoing other interventions: the fear-avoidance model
(FAM), common-sense model (CSM), expectancy theory,
and social-cognitive theory (SCT).
According to the FAM of chronic pain, psychological
factors are intrinsic to the development and maintenance of
chronic pain.11 When patients catastrophize about pain,
they come to fear pain and avoid situations/activities that
might trigger it. This inactivity (with depression, disability,
and anxiety/hypervigilance) prevents recovery and the pain
experience continues. Positive outcomes have been asso-
ciated with less catastrophizing, weaker fear-avoidance
beliefs, and less negative effect in LBP patients undergoing
conventional and/or explicitly psychological treat-
ments.11–13 If fear-avoidance processes are indeed intrinsic
to the maintenance of chronic pain and associated disability
then one would expect changes in fear-avoidance variables
Received for publication October 28, 2013; revised April 25, 2014; accepted
March 30, 2014.
From the *Department of Psychology; wSchool of Mathematics;
zMRC Lifecourse Epidemiology Unit; and ySchool of Medicine,
University of Southampton, Southampton, UK.
Supported by Arthritis Research UK (Career Development Fellowship
18099), Chesterfield, UK. G.T.L.’s post is supported by a grant
from the Rufford Maurice Laing Foundation. The remaining
authors declare no conflict of interest.
Reprints: Felicity L. Bishop, PhD, Centre for Applications of Health
Psychology, Faculty of Social and Human Sciences, Building 44
Highfield Campus, University of Southampton, Southampton
SO17 1BJ, UK (e-mail: f.l.bishop@southampton.ac.uk).
Supplemental Digital Content is available for this article. Direct URL
citations appear in the printed text and are provided in the HTML
and PDF versions of this article on the journal’s Website,
www.clinicalpain.com.
Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved. This
is an open-access article distributed under the terms of the Creative
Commons Attribution-NonCommercial-NoDerivitives 3.0 License,
where it is permissible to download and share the work provided it
is properly cited. The work cannot be changed in any way or used
commercially.
DOI: 10.1097/AJP.0000000000000108
ORIGINAL ARTICLE
254 |www.clinicalpain.com Clin J Pain Volume 31, Number 3, March 2015
to predict positive outcomes in patients undergoing
acupuncture.
According to the CSM of self-regulation of health and
illness,14 people’s perceptions of symptoms such as LBP are
organized along 5 core cognitive dimensions (identity,
consequences, controllability/cure, causes, timeline) and
guide the individual’s choice of treatment; having more
positive illness perceptions (eg, seeing LBP as more con-
trollable) leads to better health outcomes.15 The theorized
role of illness perceptions in LBP has not yet been tested in
patients receiving acupuncture but is supported by studies
of LBP patients in other settings, including chronic pain
clinics,16 primary care,17 and rehabilitation.18 An extension
of the common-sense model19,20 further suggests that,
regardless of which treatment is chosen, patients who have
positive beliefs about their treatment, practitioner, and
therapeutic relationship (eg, believing their treatment is
credible and their practitioner cares for them), are more
likely to adhere to treatment and experience positive out-
comes. Consistent with this, patients’ appraisals of the
therapeutic relationship predicted acupuncture outcomes in
1 small study21 and in clinical trials an enhanced ther-
apeutic relationship augmented the effects of acupuncture
for patients with irritable bowel syndrome22 but not
osteoarthritis.23 Questions therefore remain about the role
of acupuncture patients’ illness perceptions, treatment
beliefs, and perceptions of their practitioner/therapeutic
relationship with respect to treatment outcome.
According to expectancy theory (which was developed
and tested primarily in relation to placebo effects) response
expectancies are directly related to nonvolitional responses
including pain.24 Applied to a clinical setting, this theory
suggests that when patients expect to experience pain relief
following a particular treatment they are then more likely
to experience pain relief from that treatment. A few acu-
puncture studies have reported that patients who have more
positive expectancies have better outcomes.25–27 However,
overall the evidence for expectancy effects in acupuncture is
mixed and this inconsistency may be related to small sample
sizes and the use of various unvalidated and general ques-
tionnaires to measure expectancies.28,29
SCT is a general theory of motivation and action
which holds that self-efficacy mechanisms are central to
self-regulation processes involved in human behavior: a
strong belief in one’s capability to attain a particular goal is
causally related to one’s actual ability to attain that
goal.30,31 Applied to LBP, belief in one’s ability to cope
with pain is causally related to actual coping ability: people
with higher self-efficacy for coping are expected to commit
to more challenging goals related to coping with LBP, to
put more effort into achieving those goals, and to recover
more quickly after setbacks.32 The predicted relationship
between self-efficacy and coping ability has been demon-
strated in LBP but not specifically in patients under-
going acupuncture for LBP. For example, in 1 multivariate
analysis, illness perceptions and self-efficacy predicted
disability in LBP patients but depression, catastrophizing,
and fear-avoidance did not,33 indicating the value of con-
sidering self-efficacy alongside other psychological
variables.
To summarize, acupuncture has large nonspecific
effects that might be underpinned by psychosocial proc-
esses. Variables from the FAM, CSM, and SCT have been
associated with LBP outcomes in other settings, but there
has been an almost exclusive focus on the role of
expectancies and the therapeutic relationship in research on
psychosocial processes in acupuncture. A prospective
longitudinal observational cohort study with patients
undergoing acupuncture for LBP was conducted to test the
hypotheses that disability is associated with variables
derived from (1) FAM; (2) the CSM; (3) expectancy theory;
and (4) SCT. The aims were (1) to compare the 4 models;
(2) to identify which individual variables across all of these
models were independently associated with disability; and
(3) to test whether each variable had its effect between or
within individuals. If, as the theories suggest, psychological
processes have a causal role in maintaining back pain-
related disability and mediate changes in disability during
the course of acupuncture, then changes in psychological
factors within individuals should be directly associated with
changes in disability levels also within individuals. If psy-
chological factors predispose patients to respond to acu-
puncture (ie, moderate changes in disability), then there
should be between-person effects of psychological factors
on disability levels.
MATERIALS AND METHODS
Design and Measures
Back-related disability (the primary outcome) was
assessed 4 times: pretreatment, 2 weeks after first treatment, 3
months (when most courses of acupuncture for LBP have
been completed), and 6 months. Clinical (eg, LBP duration)
and sociodemographic characteristics (eg, age, work status)
previously associated with disability were assessed pretreat-
ment. Depression and anxiety were assessed pretreatment,
appraisals were assessed posttreatment, and all other psy-
chological predictors described below were assessed at every
measurement occasion. Self-report questionnaires were
chosen for their theoretical relevance, psychometric proper-
ties, and length (to reduce response burden). They are
described briefly here; further details are available in Sup-
plemental Digital Content 1, http://links.lww.com/CJP/A107.
Disability
The primary outcome, back pain-related disability was
assessed using the 24-item Roland Morris Disability
Questionnaire (RMDQ),34 which asks patients to think
about “today” and to indicate whether their back pain
interferes with 24 activities, for example “I stay at home
most of the time because of my back.” High scores indicate
greater back-related disability.
Fear-Avoidance Model Measures
Catastrophizing was assessed using the 6-item catas-
trophizing subscale of the Coping Strategies Ques-
tionnaire.35 Fear-avoidance beliefs about activity and work
were assessed using the 4- and 7-item subscales of the Fear-
Avoidance Beliefs Questionnaire.36 Anxiety and depression
were measured using the two 7-item subscales of the
14-item Hospital Anxiety and Depression Scale.37
Common-Sense Model Measures
Illness perceptions of back pain were measured with
the 9-item Brief Illness Perception Questionnaire.38
Responses to the free-response question that asks
respondents to name the 3 main causes of their back pain
were inductively grouped into categories, resulting in
dichotomous variables representing whether or not each
Clin J Pain Volume 31, Number 3, March 2015 Psychological Covariates of Longitudinal Changes
Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved www.clinicalpain.com |255
participant believed that their back pain was caused by:
work, disease, injury, age, and activity.
Treatment beliefs were assessed with the 3 subscales of
the Complementary and Alternative Medicine Belief
Inventory39 which measure respondents’ beliefs in holistic
approaches to health (6 items), natural treatments (6 items),
and participation in treatment (5 items). Treatment
appraisals were assessed with the Treatment Appraisal
Questionnaire,40 using the 10-item subscale measuring
appraisals of one’s therapist and 5 single items measuring
appraisals of practical aspects of treatment (eg, cost).
Appraisals of the credibility of acupuncture were assessed
with the 3-item credibility subscale of the Credibility
Expectancy Questionnaire.41 Appraisals of the acupunctu-
rist’s empathy were measured using the 10-item CARE.42
Expectancy Theory Measures
Response expectancies were measured using the 3-item
expectancy subscale of the Credibility Expectancy Ques-
tionnaire (41).
Social-Cognitive Theory Measures
Self-efficacy for coping with back pain was assessed
using the 5-item Chronic Pain Self-Efficacy for Pain Man-
agement subscale.43
Procedure and Participants
Ethics approval was obtained from Southampton and
South West Hampshire Research Ethics Committee (A) (08/
H0502/92). In the United Kingdom, many forms of acu-
puncture are available (eg, western acupuncture, traditional
Chinese acupuncture) in different types of clinic (eg, com-
plementary medicine, pain clinics) and different health care
sectors (private, National Health Service); acupuncturists
were recruited from a range of settings to reflect this diversity
(Table 1). Eighty-three acupuncturists were recruited from
across Great Britain and Northern Ireland through the Pri-
mary Care Research Network, acupuncturist associations,
and internet searches for hospital-based services.
Acupuncturists distributed baseline questionnaires
(including information and consent documents) to consec-
utive patients identified from waiting lists or at triage who
were: aged over 18 and scored at least 4 on the RMDQ.34
Patients with pain associated with cancer were excluded.
Patients returned baseline questionnaires and consent forms
by Freepost directly to the researchers, from November 2008
until October 2010. Subsequent questionnaires were posted
to participants. Gift vouchers and personalized repeated
follow-ups were sent to enhance recruitment and retention.44
Data Analysis
Within each timepoint, the proportion of missing data
was low (typically <5% missing values per variable) and
Missing at Random (according to Little’s Missing Com-
pletely at Random test) and thus missing values were
imputed using EM.45 Data were not imputed when a par-
ticipant provided no data at a particular timepoint.46 IBM
SPSS Statistics 19 was used to impute missing data and
generate descriptive statistics. There were no very high (>0.9)
bivariate correlations among predictors, suggesting absence
of problematic multicollinearity.45 LBP duration at baseline
was categorized as acute (< 6 wk), persistent (6 to 52wk), or
chronic (>52 wk).2
A longitudinal multilevel approach modeled linear
trends in disability over time using MLwiN.47 Level 1 units
were timepoints, level 2 units were individual patients, and
level 3 units were acupuncturists. Intercepts and slopes were
allowed to vary between individuals and level 2 residual
covariance (between the slope and intercept across all
individuals) was estimated. The fixed effects of clinical and
sociodemographic variables were assessed by comparison
with this 3-level model.
To assess the effects of variables on posttreatment dis-
ability, timepoint was centered on 6 months.48 Variables
measured at baseline only and measures of treatment
appraisals were included as time-invariant predictors. Other
psychological variables were included as time-varying pre-
dictors, that is, changes in these variables measured over the
study period were modeled. Time-varying predictors were
person-mean centered at level 1 (time) and level 2 (person) of
each model. The level 1 coefficient is the within-person effect
of the predictor and the level 2 coefficient is the between-
person effect.49 For example, significant positive coefficients
of catastrophizing would be interpreted as follows: at level 1,
increased catastrophizing in an individual (comparedwiththeir
own personal average level of catastrophizing) is associated
with increases in disability, when controlling for between-
person differences in catastrophizing. At level 2, higher levels
of catastrophizing overall (compared with the sample average
level of catastrophizing) are associated with higher levels of
disability compared with other people, when controlling for
within-person changes in catastrophizing over time.
A series of multilevel models tested which psychological
variables were independently associated with disability over
time after controlling for clinical and sociodemographic
characteristics that were significant in univariate analyses
(Table 1, univariate models). First, a model including clinical
and sociodemographic characteristics was specified to provide
a nested comparison model for subsequent models (Table 1,
multivariate model). Then, 4 separate models were specified to
test whether each set of psychological variables (from each
theoretical framework) was associated with disability and to
identify, within each framework, which variables were inde-
pendently associated with disability. The difference between
the 2 log-likelihoods of nested models was used to test
comparative fit.46 Finally, variables from all 4 theoretical
frameworks were entered together to identify which psycho-
logical factors overall were independently associated with
disability. For this model, plots of residuals against normal
scores, participant ID, time, and pain confirmed that level 1
and level 2 residuals were approximately normally distributed
and met assumptions of heteroscedasticity. These plots iden-
tified 4 possible outliers, but removing these participants did
not alter the fixed-effects estimates.
Throughout, Wald statistics were used to evaluate the
significance of individual variables. Pseudo-R
2
statistics
were calculated by computing and squaring the sample
correlation between observed and predicted values of dis-
ability48 and are reported as an approximate indicator of
the proportion of variance explained.
RESULTS
Clinical and Sociodemographic Characteristics,
Pain, and Well-Being
In total, 1371 baseline questionnaires were distributed
to participating acupuncturists, and completed baseline
questionnaires were received from 524 patients; 39 were
excluded for scoring <4 on the RMDQ, giving a final
Bishop et al Clin J Pain Volume 31, Number 3, March 2015
256 |www.clinicalpain.com Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved
sample at baseline of 485. The majority of participants
provided data at all 4 timepoints (n = 326, 67%) and 420
(87%) provided data at baseline and at least 1 follow-up
(Fig. 1). In logistic regression analyses, baseline disability
levels did not predict dropout (b= 0.003, SE = 0.02). Age
was the only characteristic that predicted dropout
(b= 0.05, SE = 0.01): patients who dropped out were
younger (M = 48.03, SD = 16.48) than those who did not
(M = 56.37, SD = 14.22). Of the psychological variables
measured at baseline, only timeline perceptions predicted
dropout (b= 0.14, SE = 0.06): patients who dropped out
believed their back pain would last less time (M = 7.76,
SD = 2.13) than those who did not dropout (M = 8.23,
SD = 1.97). To facilitate model comparison, the analyses
reported below are conducted on the 420 participants who
supplied data at baseline and at least 1 follow-up.
Table 1 shows participants’ clinical and sociodemo-
graphic characteristics and the effects of these factors on
disability. Characteristics that were significant univariate
predictors of disability and were thus included as covariates
in all subsequent models were: age, work status, LBP-
related benefits status, LBP-related compensation status,
reporting at least 1 comorbidity, reporting at least 1
cotreatment, duration of LBP, clinic type, and health care
sector.
Fear-Avoidance Model
Participants had moderate levels of catastrophizing
and fear-avoidance beliefs at baseline (Table 2). Mean levels
of psychological symptoms fell just below (for depression)
and just above (for anxiety) clinical cut-off points for
medical patients.50
As a set, these variables significantly improved model
fit w
2
(8) = 305.85, P< 0.001, and explained an additional
20.93% of the variance in disability beyond that accounted
for by clinical and sociodemographic characteristics.
Within individuals over time, reductions in disability were
associated with decreasing fear-avoidance beliefs about
work and/or activity and decreasing catastrophizing.
Between individuals, people who had lower levels of dis-
ability had lower levels of depression, catastrophizing, and
fear-avoidance beliefs about activity.
TABLE 1. Clinical and Sociodemographic Characteristics, and Effects on Disability
Fixed Effects on Disability Over Time
Univariate Multiplew
Variables n (%) bSE bSE
Personal characteristics
Age (mean [SD]) 55.0 (15.1) 0.03* 0.02 0.01 0.02
Sex: male 130 (31)
Sex: female 290 (69) 0.20 0.49
Education, work, and economic factors
Education: left school aged <16 y 52 (12.4)
Education: completed aged 16 y 174 (41.4) 0.14 0.72
Education: completed aged 18 y 104 (24.8) 0.74 0.78
Education: postschool education 90 (21.4) 1.50 0.79
Work: working usual job 147 (35)
Work: restricted due to back pain 95 (22.6) 4.86** 0.57 3.40** 0.58
Work: homemaker/retired/student 178 (42.4) 2.58** 0.48 1.34* 0.54
Receiving state benefits 74 (17.6) 4.34** 0.57 2.74** 0.57
Compensation claim 40 (9.5) 2.05** 0.75 1.22 0.69
Health factors
Previously had acupuncture 171 (40.7) 0.39 0.45
Comorbidity 189 (45) 1.32** 0.44 0.57 0.42
Cotreatment 330 (78.6) 1.80** 0.54 0.84 0.51
Duration: acute 53 (12.6)
Duration: persistent 136 (32.4) 0.10 0.73 0.22 0.66
Duration: chronic 231 (55) 1.83** 0.70 0.28 0.67
Cause: nonspecific 384 (91.4)
Cause: nerve compression/fracture 27 (6.4) 0.40 0.90
Cause: inflammatory condition 9 (2.1) 0.42 1.51
Clinic characteristics
Type: complementary medicine 133 (31.7)
Type: physiotherapy 112 (26.7) 0.61 0.70 2.76* 1.01
Type: pain clinic 114 (27.1) 2.56** 0.77 2.12 1.18
Type: GP 61 (14.5) 0.33 0.85 4.00** 1.22
Sector: National health service 267 (63.6)
Sector: private 153 (36.4) 1.62* 0.63 3.19** 1.04
Style: unclear 142 (33.8)
Style: western acupuncture 171 (40.7) 0.24 0.58
Style: traditional acupuncture 91 (21.7) 0.61 0.66
Style: mixed acupuncture 16 (3.8) 0.92 1.24
wMultiple model includes all significant univariate predictors of disability.
*P< 0.05.
**P< 0.01.
Clin J Pain Volume 31, Number 3, March 2015 Psychological Covariates of Longitudinal Changes
Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved www.clinicalpain.com |257
Common-Sense Model
Participants had particularly strong concerns about
their pain, thought it would last a long time, and appraised
their acupuncturist positively (Table 3). Most commonly,
participants attributed their back pain to work or other
activities.
As a set, variables from the CSM significantly
improved model fit w
2
(41) = 665.18, P< 0.001, and
explained an additional 33.76% of the variance in disability
beyond that accounted for by clinical and sociodemo-
graphic characteristics. Within individuals, reductions in
disability were associated with adaptive changes in illness
perceptions: increasing perceptions of control over back
pain (both personal control and treatment control);
improving sense of understanding back pain; associating
fewer symptoms with back pain; being less concerned about
back pain; perceiving fewer severe consequences of back
pain; and associating fewer emotions with back pain.
Between individuals, people who had lower levels of dis-
ability: attributed back pain to aging or hereditary factors,
perceived LBP as less threatening (less severe consequences,
more personal control, fewer associated symptoms), and
appraised appointments as inconvenient.
Expectancy Theory
When added to the model with clinical and socio-
demographic characteristics, expectancies significantly
improved model fit w
2
(2) = 59.21, P< 0.001, and explained
an additional 5.12% of the variance in disability. Within
individuals, reductions in disability were associated with
increasingly positive expectancies (b=0.38, SE = 0.06,
P< 0.01). Between individuals, people who had lower
levels of disability had more positive expectancies
(b=0.43, SE = 0.09, P< 0.01).
FIGURE 1. Flow diagram of participants through study. RMDQ indicates Roland Morris Disability Questionnaire.
Bishop et al Clin J Pain Volume 31, Number 3, March 2015
258 |www.clinicalpain.com Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved
Social-Cognitive Theory
At baseline, participants had moderate levels of self-
efficacy for coping (M = 52.23, SD = 18.78). Adding self-
efficacy significantly improved model fit w
2
(2) = 275.88,
P< 0.01, and explained an additional 18.90% of the var-
iance in disability beyond that explained by clinical and
sociodemographic characteristics. Within individuals,
reductions in disability were associated with increasing self-
efficacy (b=0.10, SE = 0.01, P< 0.01). Between indi-
viduals, people with lower levels of disability had higher
self-efficacy (b=0.15, SE = 0.01, P< 0.01).
Combined Model
When predictors from all the theoretical frameworks
were modeled simultaneously, variables from the FAM,
CSM, expectancy theory, and SCT were independently
associated with disability after controlling for clinical and
sociodemographic characteristics (Table 4). Within indi-
viduals, reductions in disability were associated with:
decreasing catastrophizing and fear-avoidance beliefs about
activity and work; increasing personal control over and
understanding of back pain and perceiving fewer symp-
toms, concerns, consequences, and emotions associated
with back pain; and increasing self-efficacy. Between indi-
viduals, people with lower levels of disability had lower
levels of depression and fear-avoidance beliefs about
activity; perceived less severe consequences of back pain
and greater treatment control over back pain, perceived
their back pain was caused by activities of daily living, and
appraised appointments as inconvenient; had higher
expectancies; and had higher levels of self-efficacy. Overall,
adding these psychological variables significantly improved
model fit w
2
(53) = 793.47, P< 0.01, and explained an
additional 38.16% of the variance in disability beyond that
explained by clinical and sociodemographic characteristics.
This final multilevel model incorporating variables from all
4 theoretical frameworks accounted for approximately 64%
of the variance in disability.
Exploring Causality
For each psychological variable that had a significant
within-person effect on disability in the combined model,
the direction of causality was explored. Table 5 shows the
b-coefficients of models in which (1) disability scores at 3
months were regressed on changes in psychological varia-
bles from baseline to 2 weeks; and (2) scores on psycho-
logical variables at 3 months were regressed on changes in
disability from baseline to 2 weeks. Changes in disability
early in treatment predicted fear-avoidance, catas-
trophizing, self-efficacy, and perceptions of personal control
at 3 months but not vice versa. Increased understanding of
back pain early in treatment predicted disability at 3 months
but not vice versa. Other illness perceptions (consequences,
identity, and concerns) had reciprocal relationships with
disability: early changes in illness perceptions predicted
disability at 3 months and early changes in disability pre-
dicted illness perceptions at 3 months.
DISCUSSION
As hypothesized, variables derived from expectancy
theory, FAM, CSM, and SCT were associated with changes
in disability among back pain patients receiving acu-
puncture. The final model showed that variables from these
theoretical frameworks had independent effects and,
together with clinical and socio-demographic character-
istics, accounted for two thirds of the variance in disability.
Within-individual reductions in disability were con-
sistently associated with decreases in: fear-avoidance beliefs
about physical activity and work; catastrophizing; per-
ceived symptoms associated with LBP; concerns about
LBP; perceived consequences of LBP; and emotions asso-
ciated with LBP. Within-individual reductions in disability
were consistently associated with increases in: perceived
personal control over LBP; perceived comprehension of
LBP; and self-efficacy for coping with LBP. Further anal-
ysis suggested that changes in fear-avoidance beliefs and
self-efficacy for coping may be epiphenomenal and occur
after changes in disability, although it is possible that our
measurement points were too far apart in time to capture
what might be a very close reciprocal relationship between
changes in fear-avoidance beliefs, self-efficacy, and dis-
ability. Changes in illness perceptions appeared to both lead
to and result from changes in disability, which is consistent
with the idea that illness perceptions evolve over time and
patients’ perceptions of their symptoms influence their
concrete experiences of therapy which in turn can feedback
and modify their illness perceptions.19,51 The results of this
study suggest that illness perceptions appear to be
TABLE 2. Fear-Avoidance Model: Baseline Values and Fixed Effects on Disability Over Time
Fixed Effect on Disability Over TimewBaseline Values
Predictors bSE M SD a
Anxiety 0.03 0.06 9.26 4.15 0.83
Depression 0.25** 0.06 6.92 3.89 0.83
Fear-avoidance beliefs—activity 15.01 5.50 0.74
Between-persons effect 0.21** 0.04
Within-persons effect 0.21** 0.03
Fear-avoidance beliefs—work 13.36 14.43 0.88
Between-persons effect 0.02 0.02
Within-persons effect 0.04** 0.01
Catastrophizing 2.52 1.57 0.90
Between-persons effect 0.85** 0.16
Within-persons effect 0.76** 0.12
wAdjusted for clinical and sociodemographic characteristics: age, work status, low back pain (LBP)-related benefits status, LBP-related compensation
status, reporting at least 1 comorbidity, reporting at least 1 cotreatment, duration of LBP, clinic type, and health care sector.
**P< 0.01 (Wald test for fixed parameters).
Clin J Pain Volume 31, Number 3, March 2015 Psychological Covariates of Longitudinal Changes
Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved www.clinicalpain.com |259
TABLE 3. Common-Sense Model: Baseline Values and Effects on Disability Over Time
Fixed Effect on Disability Over TimewBaseline Values
bSE M SD a
Illness perceptions
Consequences 7.33 1.79
Between-persons effect 1.04** 0.16
Within-persons effect 0.35** 0.08
Timeline 8.17 1.99
Between-persons effect 0.03 0.11
Within-persons effect 0.02 0.07
Personal control 3.85 2.29
Between-persons effect 0.24* 0.11
Within-persons effect 0.24** 0.05
Treatment control 6.58 2.03
Between-persons effect 0.02 0.14
Within-persons effect 0.13* 0.06
Identity 7.37 1.75
Between-persons effect 0.39* 0.16
Within-persons effect 0.44** 0.08
Concerns 8.60 1.55
Between-persons effect 0.13 0.14
Within-persons effect 0.28** 0.08
Comprehension 6.50 2.79
Between-persons effect 0.12 0.08
Within-persons effect 0.13* 0.06
Emotions 6.76 2.44
Between-persons effect 0.16 0.10
Within-persons effect 0.26** 0.06
Caused by activities of daily living (n [%]) 140 (28.9)
Between-persons effect 0.57 0.47
Within-persons effect 0.40 0.25
Caused by work/activities (n [%]) 293 (60.4)
Between-persons effect 0.03 0.40
Within-persons effect 0.13 0.25
Caused by accident/injury (n [%]) 167 (34.4)
Between-persons effect 0.10 0.41
Within-persons effect 0.31 0.31
Caused by age or genes (n [%]) 138 (28.5)
Between-persons effect 0.87* 0.42
Within-persons effect 0.33 0.28
Caused by a disease or illness (n [%]) 117 (24.1)
Between-persons effect 0.19 0.43
Within-persons effect 0.08 0.32
Treatment beliefs
Credibility 0.08 2.60 0.89
Between-persons effect 0.20 0.12
Within-persons effect 0.04 0.06
Holistic health 30.05 5.42 0.61
Between-persons effect 0.06 0.04
Within-persons effect 0.04 0.03
Natural treatments 31.89 6.40 0.82
Between-persons effect 0.04 0.03
Within-persons effect 0.00 0.03
Participation in treatment 26.76 4.43 0.62
Between-persons effect 0.01 0.04
Within-persons effect 0.02 0.03
Treatment appraisals
Not too expensive (n [%]) 0.28 0.41 150 (35.7)
Value for money (n [%]) 0.37 0.49 114 (27.1)
Convenient appointments (n [%]) 1.25** 0.43 143 (34.0)
Not difficult to travel to appointments (n [%]) 0.53 0.45 222 (52.9)
Not effortful (n [%]) 0.04 0.46 262 (62.4)
Perceptions of empathy 0.05 0.03 41.38 8.93 0.97
Perceptions of acupuncturist 0.06 0.03 59.71 9.76 0.91
wAdjusted for clinical and sociodemographic characteristics: age, work status, low back pain (LBP)-related benefits status, LBP-related compensation
status, reporting at least 1 comorbidity, reporting at least 1 cotreatment, duration of LBP, clinic type, and health care sector.
*P< 0.05.
**P< 0.01 (Wald test for fixed parameters).
Bishop et al Clin J Pain Volume 31, Number 3, March 2015
260 |www.clinicalpain.com Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved
mediators of changes in disability over the course of acu-
puncture treatment and they could be deliberately targeted
clinically to enhance acupuncture’s effectiveness.
Variables that only had a between-person effect are
possible moderators of changes in disability over the course
of acupuncture treatment. People who had lower levels of
disability appraised appointments as inconvenient and had
higher outcome expectancies. Appraisals were measured
after 2 weeks of treatment and so it might be that people
who were less disabled early in treatment were less moti-
vated to attend appointments and so appraised them as
inconvenient. Having low expectations of benefit might be a
marker for acupuncture patients at high risk of relatively
poor outcome.
The findings have implications for how we theorize
disability in patients with LBP undergoing treatment. Each
of our models explained some of the variance in changes in
disability over time; conceptually, the theories provide
somewhat complementary but at times overlapping
insights. The fear-avoidance model11 focuses on emotional
representations, whereas the common-sense model14 better
elaborates cognitive illness representations. Self-efficacy for
coping overlaps conceptually with perceptions of personal
control from the common-sense model. Both the extended
CSM19,20 and expectancy theory24 emphasize treatment
cognitions, which in this study distinguished between peo-
ple who also reported different levels of disability but were
rarely associated with individual changes in disability.
Although no single theoretical framework provided a
complete account of the psychological factors involved in
disability, we found that changes in illness perceptions were
the most likely to be causally related to improvements in
LBP-related disability over time, at least during acu-
puncture treatment. Given that psychological theories
implicitly focus on within-person processes, analytic
TABLE 4. Effects of Variables From 4 Theoretical Frameworks on
Disability Over Time
Fixed Effect on
Disability Over Timew
Predictors bSE
Fear-avoidance model
Anxiety 0.08 0.05
Depression 0.14** 0.05
Fear-avoidance beliefs—activity
Between-persons effect 0.12** 0.03
Within-persons effect 0.11** 0.03
Fear-avoidance beliefs—work
Between-persons effect 0.00 0.02
Within-persons effect 0.03* 0.01
Catastrophizing
Between-persons effect 0.09 0.16
Within-persons effect 0.28** 0.11
Common-sense model: illness perceptions
Consequences
Between-persons effect 0.87** 0.15
Within-persons effect 0.28** 0.08
Timeline
Between-persons effect 0.11 0.10
Within-persons effect 0.03 0.07
Personal control
Between-persons effect 0.07 0.11
Within-persons effect 0.17** 0.05
Treatment control
Between-persons effect 0.41** 0.15
Within-persons effect 0.05 0.07
Identity
Between-persons effect 0.28 0.15
Within-persons effect 0.43** 0.08
Concerns
Between-persons effect 0.18 0.13
Within-persons effect 0.17* 0.08
Comprehension
Between-persons effect 0.13 0.07
Within-persons effect 0.11* 0.05
Emotions
Between-persons effect 0.08 0.11
Within-persons effect 0.16* 0.06
Caused by activities of daily living
Between-persons effect 0.88* 0.44
Within-persons effect 0.42 0.24
Caused by work/activities
Between-persons effect 0.26 0.39
Within-persons effect 0.08 0.24
Caused by accident/injury
Between-persons effect 0.16 0.38
Within-persons effect 0.28 0.30
Caused by age or genes
Between-persons effect 0.67 0.39
Within-persons effect 0.27 0.27
Caused by a disease or illness
Between-persons effect 0.55 0.41
Within-persons effect 0.06 0.31
Common-sense model: treatment beliefs
Credibility
Between-persons effect 0.03 0.13
Within-persons effect 0.00 0.07
Holistic health
Between-persons effect 0.02 0.04
Within-persons effect 0.04 0.03
Natural treatments
Between-persons effect 0.02 0.03
Within-persons effect 0.00 0.03
(Continued )
TABLE 4. (continued)
Fixed Effect on
Disability Over Timew
Predictors bSE
Participation in treatment
Between-persons effect 0.01 0.04
Within-persons effect 0.01 0.03
Common-sense model: treatment appraisals
Not too expensive 0.28 0.38
Value for money 0.43 0.45
Convenient appointments 0.92* 0.40
Not difficult to travel to appointments 0.23 0.42
Not effortful 0.16 0.43
Perceptions of empathy 0.04 0.03
Perceptions of acupuncturist 0.05 0.03
Expectancy theory: expectancies
Between-persons effect 0.30* 0.15
Within-persons effect 0.04 0.07
Social-cognitive theory: self-efficacy for coping with pain
Between-persons effect 0.07** 0.02
Within-persons effect 0.04** 0.01
wAdjusted for clinical and sociodemographic characteristics: age, work
status, low back pain (LBP)-related benefits status, LBP-related compensa-
tion status, reporting at least 1 comorbidity, reporting at least 1 cotreatment,
duration of LBP, clinic type, and health care sector.
*P< 0.05.
**P< 0.01 (Wald test for fixed parameters).
Clin J Pain Volume 31, Number 3, March 2015 Psychological Covariates of Longitudinal Changes
Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved www.clinicalpain.com |261
techniques to distinguish within and between-person effects
(such as those used here) could inform further theoretical
development.
Other studies have looked at smaller subsets of the
variables we investigated in different settings. In 1 RCT of
physical therapy and CBT for chronic back pain, expect-
ancy predicted disability and satisfaction with treatment,
whereas credibility predicted symptoms and satisfaction.52
In a mixed cohort of patients with neck and/or back pain,
fear-avoidance beliefs, negative affect, and expecting pain
to persist (similar to timeline beliefs) all independently
predicted disability.53 Cross-sectional studies show that
self-efficacy is a stronger mediator between pain and dis-
ability and a stronger correlate of disability than fear-
avoidance variables in chronic and acute pain.54,55 A
longitudinal study in primary care reported that changes in
self-efficacy, but not fear-avoidance beliefs, mediated the
relationship between pain and disability.56 Fewer studies
have investigated the common-sense model. Foster et al,33
investigated fear-avoidance variables, self-efficacy, and ill-
ness perceptions (but not other components, ie, treatment
beliefs and appraisals) in a primary care LBP cohort. The
significant independent predictors of disability were identity
beliefs (perceived symptoms), personal control beliefs,
timeline beliefs, and pain self-efficacy; fear-avoidance vari-
ables tended to be weaker predictors.33 The present study
contributes to this evidence that self-efficacy and illness
perceptions in particular can usefully supplement variables
from the fear-avoidance model in advancing our under-
standing of back pain-related disability and suggests that
these variables are relevant in acupuncture as well as con-
ventional treatment settings. A single study of people
receiving different LBP therapies is needed to compare the
relative importance of psychological variables across vari-
ous therapeutic modalities and clinical settings.
The findings also have implications for understanding
acupuncture’s large nonspecific effects6and, more gen-
erally, for understanding the processes whereby acu-
puncture may result in decreased disability. Given that
similar variables predict disability in other settings,
patients’ perceptions of pain and self-efficacy could be
influencing disability outcomes in patients receiving both
real and sham acupuncture in clinical trials. These psy-
chological variables offer one means by which major com-
ponents of acupuncture as a complex intervention, such as
ritual,57 the therapeutic relationship,22 and lifestyle
advice,58 could trigger positive clinical outcomes. In the
context of a warm relationship and therapeutic ritual,
providing positive self-help advice encouraging physical
activity could help patients to develop more positive illness
perceptions, confront their fear of activities and become
more active, breaking the negative cycle proposed in the
fear-avoidance model11 and triggering a more positive
perception of back pain as controllable and enabling an
increasing sense of self-efficacy for coping. According to
social-cognitive theory, enhanced self-efficacy for coping
could then trigger a positive feedback loop increasing actual
coping ability30 and reducing disability.
Expectancies were associated with disability between-
persons but not within-persons. Previous acupuncture
studies are inconsistent28,29 but the placebo literature
strongly suggests that enhancing expectancies can generate
placebo analgesia.24 Perhaps, and consistent with the
present results, expectancy might have an indirect effect
mediated by pain perceptions: positive response expectancy
might help to reduce perceptions of pain as threatening and
thus facilitate the development of more adaptive pain per-
ceptions and coping behaviors.
Treatment beliefs and appraisals of the acupuncturist
were consistently weakly associated with disability. Previous
studies found treatment beliefs and perceived empathy were
relatedtoadherence
40 and enablement.21 Treatment beliefs
and appraisals might be more important for such proximal
outcomes than for distal outcomes like disability. The meas-
ure of treatment beliefs used in this study may have been too
general as it assessed beliefs about complementary therapies
rather than acupuncture in particular.
The generalizability of the findings is enhanced by the
large cohort of back pain patients receiving acupuncture in
usual care and the limited exclusion criteria. However, the
representativeness of the sample is difficult to assess.
Compared with a national (UK) survey of acupuncture
TABLE 5. Exploring Causality Between Psychological Variables and Disability
Fixed Effect of
Changes in Psychological
Variable on Disability at 3 mow
Changes in Disability on
Psychological Variable at 3 mow
Psychological Variables bSE bSE
Fear-avoidance model
Fear-avoidance beliefs—activity 0.10 0.07 0.21** 0.08
Fear-avoidance beliefs—work 0.07 0.04 0.04 0.18
Catastrophizing 0.25 0.31 0.05* 0.02
Common-sense model: illness perceptions
Consequences 0.42* 0.20 0.18** 0.03
Personal control 0.16 0.14 0.12** 0.03
Identity 0.46* 0.19 0.14** 0.03
Concerns 0.44* 0.22 0.14** 0.03
Comprehension 0.30* 0.15 0.05 0.03
Emotions 0.10 0.17 0.07 0.04
Social-cognitive theory
Self-efficacy for coping with pain 0.01 0.02 1.26** 0.27
wChange variables computed by subtracting score at 2 weeks from score at baseline.
*P< 0.05.
**P< 0.01.
Bishop et al Clin J Pain Volume 31, Number 3, March 2015
262 |www.clinicalpain.com Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved
users with various conditions,3participants were similar in
age (51 y) and sex (68% vs. 74% females) but fewer had
previous acupuncture experience (42% vs. 87%) and more
used acupuncture in the National Health Servic (63% vs.
5%). Compared with a large cohort of primary care LBP
patients,17 participants were older (51 vs. 44 y), more disabled
at baseline (mean RMDQ 13.4 vs. 8.6), and more were female
(68% vs. 59%). Although some participants were lost to
follow-up, attrition was not associated with disability. Com-
pared with other acupuncture studies, a large and theoret-
ically grounded set of confounders and predictors were
measured. A smaller selection of predictors could be used in
future but should include illness perceptions (most likely to
prospectively predict within-person changes), self-efficacy,
and expectancy (for between-person differences).
In conclusion, cognitive and emotional pain perceptions
and self-efficacy for coping with pain are associated with
changes in disability over the course of acupuncture for LBP.
Changes in illness perceptions may predict subsequent dis-
ability, whereas changes in disability appear to predict sub-
sequent self-efficacy and fear-avoidance beliefs. Self-efficacy
and, in particular, illness perceptions can usefully supplement
variables from the fear-avoidance model in advancing our
understanding of back pain-related disability. Acupuncture
patients experience less back-related disability when they are
less afraid and avoidant of physical activity and work, per-
ceive fewer symptoms emotions and consequences of LBP,
perceive their LBP as less threatening, and when they feel
greater control over, understanding of, and ability to cope
with their back pain. Future studies should test whether
integrating acupuncture and psychological interventions tar-
geting these constructs can enhance patient outcomes.
ACKNOWLEDGMENTS
The authors are grateful to the Primary Care Research
Network, the Acupuncture Association of Chartered Physi-
otherapists, and British Acupuncture Council, and the British
Medical Acupuncture Society for help recruiting acupunctu-
rists. They are grateful to the acupuncturists for recruiting
our participants and to the participants for completing the
questionnaires. They thank Jane Cousins, Naomi Guppy, and
Gemma Fitzsimmons; (School of Medicine, University of
Southampton, Southampton, UK) for administrative support.
REFERENCES
1. Breivik H, Collett B, Ventafridda V, et al. Survey of chronic
pain in Europe: prevalence, impact on daily life, and treatment.
Eur J Pain. 2006;10:287–333.
2. Savigny P, Kuntze S, Watson P, et al. Low Back Pain. Early
Management of Persistent Non-Specific Low Back Pain. NICE
Clinical Guideline. 88 ed. London: National Collaborating Centre
for Primary Care and Royal College of General Practitioners;
2009. Available at: http://www.nice.org.uk/CG88.
3. MacPherson H, Sinclair-Lian N, Thomas K. Patients seeking
care from acupuncture practitioners in the UK: a national
survey. Complement Ther Med. 2006;14:20–30.
4. Brinkhaus B, Witt CM, Jena S, et al. Acupuncture in patients
with chronic low back pain—a randomized controlled trial.
Arch Intern Med. 2006;166:450–457.
5. Vickers AJ, Cronin AM, Maschino AC, et al. Acupuncture for
chronic pain: individual patient data meta-analysis. Arch Intern
Med. 2012;172:1444–1453.
6. Linde K, Niemann K, Schneider A, et al. How large are the
nonspecific effects of acupuncture? A meta-analysis of
randomized controlled trials. BMC Med. 2010;8:75.
doi:10.1186/1741-7015-8-75.
7. Paterson C, Dieppe P. Characteristic and incidental (placebo)
effects in complex interventions such as acupuncture. BMJ.
2005;330:1202–1205.
8. MacPherson H, Thorpe L, Thomas K. Beyond needling—
therapeutic processes in acupuncture care: a qualitative study
nested within a low-back pain trial. J Altern Complement Med.
2006;12:873–880.
9. Paterson C, Evans M, Bertschlinger R, et al. Communication
about self-care in traditional acupuncture consultations: the
co-construction of individualised support and advice. Patient
Educ Couns. 2012;89:467–475.
10. Rugg S, Paterson C, Britten N, et al. Traditional acupuncture
for people with medically unexplained symptoms: a longi-
tudinal qualitative study of patients’ experiences. Br J Gen
Pract. 2011;61:e306–e315.
11. Vlaeyen JWS, Linton SJ. Fear-avoidance and its consequences
in chronic musculoskeletal pain: a state of the art. Pain.
2000;85:317–332.
12. Leeuw M, Goossens MEJB, Linton SJ, et al. The fear-
avoidance model of musculoskeletal pain: current state of
scientific evidence. J Behav Med. 2007;30:77–94.
13. Bailey KM, Carleton RN, Vlaeyen JWS, et al. Treatments
addressing pain-related fear and anxiety in patients with
chronic musculoskeletal pain: a preliminary review. Cogn
Behav Ther. 2009;39:46–63.
14. Leventhal HA, Brissette I, Leventhal EA. The common-sense
model of self-regulation of health and illness. In: Cameron LD,
Leventhal H, eds. The Self-Regulation of Health and Illness
Behaviour. London: Routledge; 2003:42–65.
15. Hagger MS, Orbell S. A meta-analytic review of the common-
sense model of illness representations. Psychol Health.
2003;18:141–184.
16. Nicklas LB, Dunbar M, Wild M. Adherence to pharmaco-
logical treatment of non-malignant chronic pain: the role of
illness perceptions and medication beliefs. Psychol Health.
2009;25:601–615.
17. Foster NE, Bishop A, Thomas E, et al. Illness perceptions of
low back pain patients in primary care: what are they, do they
change and are they associated with outcome? Pain.
2008;136:177–187.
18. Glattacker M, Heyduck K, Meffert C. Illness beliefs, treatment
beliefs and information needs as starting points for patient
information—evaluation of an intervention for patients with
chronic back pain. Patient Educ Couns. 2012;86:378–389.
19. Yardley L, Sharples K, Beech S, et al. Developing a dynamic
model of treatment perceptions. JHealthPsychol. 2001;6:269–282.
20. Horne R, Weinman J. Self-regulation and self-management in
asthma: exploring the role of illness perceptions and treatment
beliefs in explaining non-adherence to preventer medication.
Psychol Health. 2002;17:17–32.
21. Price S, Mercer SW, MacPherson H. Practitioner empathy,
patient enablement and health outcomes: a prospective study
of acupuncture patients. Patient Educ Couns. 2006;63:239–245.
22. Kaptchuk TJ, Kelley JM, Conboy LA, et al. Components of
placebo effect: randomised controlled trial in patients with
irritable bowel syndrome. BMJ. 2008;336:999–1003.
23. White P, Bishop FL, Prescott P, et al. Practice, practitioner or
placebo? A multifactorial, mixed methods randomized con-
trolled trial of acupuncture. Pain. 2012;153:455–462.
24. Kirsch I. Response expectancy theory and application: a
decennial review. Appl Prev Psychol. 1997;6:69–79.
25. Kalauokalani D, Cherkin DC, Sherman KJ, et al. Lessons
from a trial of acupuncture and massage for low back pain.
Spine. 2001;26:1418–1424.
26. Linde K, Witt CM, Streng A, et al. The impact of patient
expectations on outcomes in four randomized controlled trials
of acupuncture in patients with chronic pain. Pain. 2007;
128:264–271.
27. Suarez-Almazor ME, Looney C, Liu Y, et al. A randomized
controlled trial of acupuncture for osteoarthritis of the knee:
effects of patient-provider communication. Arthritis Care Res.
2010;62:1229–1236.
Clin J Pain Volume 31, Number 3, March 2015 Psychological Covariates of Longitudinal Changes
Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved www.clinicalpain.com |263
28. Sherman KJ, Cherkin DC, Ichikawa L, et al. Treatment
expectations and preferences as predictors of outcome of
acupuncture for chronic back pain. Spine. 2010;35:1471–1477.
29. Colagiuri B, Smith CA. A systematic review of the effect of
expectancy on treatment responses to acupuncture. eCAM.
2012. doi:10.1155/2012/857804.
30. Bandura A. Self-Efficacy. The Exercise of Control. New York:
W.H. Freeman and Company; 1997.
31. Bandura A. Social cognitive theory of self-regulation. Organ
Behav Hum Dec. 1991;50:248–287.
32. Schwarzer R, Fuchs R. Self-efficacy and health behaviours. In:
Conner M, Norman P, eds. Predicting Health Behaviour:
Research and Practice With Social Cognition Models. Buck-
ingham: Open University Press; 1995:163–196.
33. Foster NE, Thomas E, Bishop A, et al. Distinctiveness of
psychological obstacles to recovery in low back pain patients in
primary care. Pain. 2010;148:398–406.
34. Roland M, Morris R. A study of the natural history of back
pain. Part I: development of a reliable and sensitive measure of
disability in low-back pain. Spine. 1983;8:141–144.
35. Rosentiel AK, Keefe FJ. The use of coping strategies in
chronic low back pain patients: relationship to patient
characteristics and current adjustment. Pain. 1983;17:
33–44.
36. Waddell G, Newton M, Henderson I, et al. A fear-avoidance
beliefs questionnaire (FABQ) and the role of fear-avoidance
beliefs in chronic low back pain and disability. Pain.
1993;52:157–168.
37. Zigmond AS, Snaith RP. The Hospital Anxiety and
Depression Scale. Acta Psychiatr Scand. 1983;67:361–370.
38. Broadbent E, Petrie KJ, Main J, et al. The Brief Illness
Perception Questionnaire. J Psychosom Res. 2006;60:631–637.
39. Bishop FL, Yardley L, Lewith G. Developing a measure of
treatment beliefs: the Complementary and Alternative Medicine
Beliefs Inventory. Complement Ther Med. 2005;13:144–149.
40. Bishop FL, Yardley L, Lewith GT. Treatment appraisals and
beliefs predict adherence to complementary therapies: a
prospective study using a dynamic extended self-
regulation model. Br J Health Psychol. 2008;13:701–718.
41. Devilly GJ, Borkovec TD. Psychometric properties of the
credibility/expectancy questionnaire. J Behav Ther Exp Psy-
chiatry. 2000;31:73–86.
42. Mercer SW, Maxwell M, Heaney D, et al. The development
and preliminary validation of the Consultation and Relational
Empathy (CARE) measure: an empathy-based consultation
process measure. Fam Pract. 2004;21:699–705.
43. Anderson KO, Dowds BN, Pelletz RE, et al. Development and
initial validation of a scale to measure self-efficacy beliefs in
patients with chronic pain. Pain. 1995;63:77–83.
44. Edwards P, Roberts I, Clarke M, et al. Increasing response
rates to postal questionnaires: systematic review. BMJ.
2002;324:1183–1193.
45. Tabachnick BG, Fidell LS. Using Multivariate Statistics.
Boston: Allyn and Bacon; 2001.
46. Twisk JWR. Applied Longitudinal Data Analysis for Epidemiol-
ogy. Cambridge: Cambridge University Press; 2003.
47. Rasbash J, Charlton C, Browne WJ, et al. MLwiN Version 2.1.
University of Bristol: Centre for Multilevel Modelling; 2009.
48. Singer JD, Willett JB. Applied Longitudinal Data Analysis.
Oxford: Oxford University Press; 2003.
49. Hoffman L, Stawski RS. Persons as contexts: evaluating
between-person and within-person effects in longitudinal
analysis. Res Hum Dev. 2009;6:97–120.
50. Bjelland I, Dahl AA, Haug TT, et al. The validity of the
Hospital Anxiety and Depression Scale: an updated literature
review. J Psychosom Res. 2002;52:69–77.
51. Leventhal H, Leventhal EA, Contrada RJ. Self-regulation,
health, and behavior: a perceptual-cognitive approach. Psychol
Health. 1998;13:717–733.
52. Smeets RJEM, Beelen S, Goossens MEJB, et al. Treatment
expectancy and credibility are associated with the outcome of
both physical and cognitive-behavioral treatment in chronic
low back pain. Clin J Pain. 2008;24:305–315.
53. Boersma K, Linton SJ. Expectancy, fear and pain in the
prediction of chronic pain and disability: a prospective
analysis. Eur J Pain. 2006;10:551–557.
54. Woby SR, Urmston M, Watson PJ. Self-efficacy mediates the
relation between pain-related fear and outcome in chronic low
back pain patients. Eur J Pain. 2007;11:711–718.
55. So
¨derlund A, A
˚senlo
¨f P. The mediating role of self-efficacy
expectations and fear of movement and (re)injury beliefs in two
samples of acute pain. Disabil Rehabil. 2010;32:2118–2126.
56. Costa Ld, Maher CG, McAuley JH, et al. Self-efficacy is more
important than fear of movement in mediating the relationship
between pain and disability in chronic low back pain. Eur J
Pain. 2011;15:213–219.
57. Kaptchuk TJ. The placebo effect in alternative medicine: can
the performance of a healing ritual have clinical significance?
Ann Intern Med. 2002;136:817–825.
58. MacPherson H, Thomas K. Self-help advice as a process
integral to traditional acupuncture care: implications for trial
design. Complement Ther Med. 2008;16:101–106.
Bishop et al Clin J Pain Volume 31, Number 3, March 2015
264 |www.clinicalpain.com Copyright r2014 Wolters Kluwer Health, Inc. All rights reserved
