Psychol. Inj. and Law DOI 10.1007/s12207-015-9247-x
Psychometric Properties of a Brief Instrument to Assess Perceptions of Injustice Associated with Debilitating Health and Mental Health Conditions Michael J. L. Sullivan 1 & Heather Adams 2 & Esther Yakobov 1 & Tamra Ellis 3 & Pascal Thibault 1
Received: 21 December 2015 / Accepted: 23 December 2015 # Springer Science+Business Media New York 2016
Abstract The present study examined the psychometric properties of a shortened and simplified version of the Injustice Experience Questionnaire (IEQ). The instructional set of the original IEQ was modified to make it better suited to the context of debilitating health and mental health conditions that do not necessarily arise as a result of injury. The number of items was reduced from 12 to 5, and the response scale was simplified. The Injustice Experiences Questionnaire – Short Form (IEQ-SF) was administered to individuals diagnosed with a chronic musculoskeletal (MSK) condition (N = 88) or major depressive disorder (MDD) (N = 87). The internal consistency of the IEQ-SF was acceptable. The IEQ-SF was significantly correlated with measures of pain severity, depressive symptom severity and disability in both samples. Individuals with MDD scored higher on the IEQ-SF than individuals with MSK. The IEQ-SF was shown to be sensitive to treatment-related reductions in perceived injustice. Preliminary analyses suggest that the IEQ-SF is a reliable and valid measure of disability-related injustice perceptions associated with debilitating health and mental health conditions.
Keywords Perceived injustice . Depression . Pain . Disability
* Michael J. L. Sullivan
[email protected]
1
Department of Psychology, McGill University, 1205 Doctor Penfield Avenue, Montreal, QC H3A 1B1, Canada
2
Department of Surgery, McGill University Health Centre, Montreal, QC, Canada
3
Centre for Rehabilitation and Health, Montreal, QC, Canada
Introduction Perceived injustice has recently emerged as a psychological factor that contributes to delayed recovery following injury (Sullivan, Adams, Martel, Scott, & Wideman, 2011). In the context of debilitating injury, perceived injustice has been conceptualized as an appraisal process characterized by a tendency to construe one’s losses as severe and irreparable and to attribute blame to others for one’s suffering (Sullivan, Adams, Horan, Maher, Boland, & Gross, 2008). Perceptions of injustice are likely to arise in circumstances under which individuals consider that they have suffered undeserved losses or hardship (Lerner, 1977; Lind & Tyler, 1988; Miller, 2001). The relation between perceived injustice and adverse recovery outcomes has been demonstrated among individuals suffering from a wide range of debilitating pain conditions including whiplash injury (Scott, Trost, Milioto, & Sullivan, 2013), work-related low back pain (Sullivan et al., 2008), fibromyalgia (Rodero, Luciano, Montero-Marin, Casanueva, Palacin, Gili et al., 2012), sickle cell disease (Ezenwa, Molokie, Wilkie, Suarez, & Yao, 2014), osteoarthritis (Yakobov, Scott, Stanish, Dunbar, Richardson, & Sullivan, 2014; Yakobov, Scott, Tanzer, Stanish, Dunbar, Richardson et al., 2014a) and rheumatoid arthritis (Ferrari & Russell, 2014). The relation between perceived injustice and problematic recovery outcomes has been shown even when controlling for other pain-related psychosocial risk factors such as pain catastrophizing, fear of pain and depression (Sullivan, Scott, & Trost, 2012). To date, the bulk of research examining the relation between perceived injustice and recovery outcomes has been conducted using the Injustice Experiences Questionnaire (IEQ). The IEQ consists of 12 items reflecting various justice-related appraisals relevant to the experience of injury. Respondents are asked to indicate the frequency with which
Psychol. Inj. and Law
they experience each thought on a 5-point scale with the endpoints (0) never and (4) all the time. Research shows that the IEQ has high internal consistency (alpha = 0.92) and high testretest reliability (r = 0.90). Studies on the psychometric properties of the IEQ reveal that the scale comprises two correlated factors that have been labeled severity/irreparability of loss and blame/unfairness (Sullivan et al., 2008; Yakobov, Scott, et al., 2014a). One limitation of the IEQ is that the instructional set is worded specifically in relation to an injury that the respondent has sustained. Although a number of studies have modified the instructional set of the IEQ in order to assess perceptions of injustice associated with health conditions not related to injury (e.g. osteoarthritis, fibromyalagia), variations in wording of the scale instructions limit the nature of cross-study comparisons that can be made (Yakobov, Scott, et al., 2014b). Another limitation of the IEQ is that its current length (12 items) limits its use as a screening instrument. Screening procedures such as those used in risk assessment by injury or disability insurers require measures that are short and can be administered in alternate formats such as by telephone. The high internal consistency of the IEQ suggests that it might be possible to shorten the instrument and simplify the response scale without negatively affecting its psychometric properties. The present study examined the psychometric properties of a modified version of the IEQ that could be suitable for individuals suffering from a wide range of debilitating health and mental health conditions. The instructional set of the original IEQ was modified such that individuals were asked to respond to the scale items in relations to their ‘health or mental health condition’. The number of items was reduced to 5, and the response scale was changed to a 3-point frequency scale. The psychometric properties of the Injustice Experiences Questionnaire – Short Form (IEQ-SF) were examined in a sample of individuals who were work-disabled due to a musculoskeletal condition and a sample of individuals who were work-disabled due to a depressive condition. The pattern of findings was compared to previous research using the original version of the IEQ. Proceeding from previous research on perceived injustice and injury outcomes, it was expected that the IEQ-SF would have acceptable internal consistency and that high scores on IEQ-SF would be correlated with symptom severity and disability. It was also predicted that the IEQ-SF would be responsive to change following treatment designed to reduce perceptions of injustice.
depression. Data were drawn from the clinical files of consecutive referrals to a rehabilitation centre specializing in vocational programs for work-disabled individuals. Selection criteria for data extraction included a primary diagnosis of (1) musculoskeletal pain (involving the spine) or (2) major depressive disorder. Individuals with co-morbid health or mental health conditions (e.g. MDD + MSK) were not considered for participation. All participants were receiving longterm disability benefits when they were referred to the rehabilitation centre. Information about participants’ diagnoses was taken from the participants’ long-term disability insurance files. Access to disability benefits requires that the diagnosis of a debilitating health or mental health condition be confirmed by a medical or mental health specialist. Measures Perceived Injustice The IEQ-SF is a 5-item measure designed to assess perceptions of injustice associated with the experience of a debilitating health or mental health condition. The 5 items of the IEQSF were drawn from the original IEQ (items 1, 2, 4, 5, 6). Item analyses were conducted on data sets used in previous studies using the original IEQ, and the items most strongly correlated with pain severity, severity of depression and disability were retained. The instructional set of the IEQ-SF was modified from the original IEQ such that individuals were asked to respond to the questionnaire items in relation to their ‘health or mental health condition’ as opposed to their ‘injury’ (Sullivan et al., 2008). The instructional set for the IEQ-SF is as follows: Disabling health and mental health conditions can have profound effects on our lives. This scale was designed to assess how your health or mental health condition has affected your life. Listed below are five statements describing different thoughts and feelings that you might experience when you think about your health or mental health condition. Using the following scale, please indicate the degree to which you have these thoughts and feelings when you think about your health or mental health condition.
Methods
The response scale of the IEQ-SF was modified from a 5point frequency scale, used in the original IEQ, to a 3-point frequency scale with the anchors (0) never, (1) sometimes and (2) often. The 5 items of the IEQ-SF appear in Table 1.
Participants
Depressive Symptoms
The study sample included 88 work-disabled individuals with musculoskeletal pain and 87 work-disabled individuals with
The Patient Health Questionnaire-9 (PHQ-9) was used to assess the severity of depressive symptoms. Respondents were
Psychol. Inj. and Law Table 1 IEQ-SF items Item #
MSK
MDD
P
IEQ-SF1 IEQ-SF2
Most people don’t understand how severe my condition is. My life will never be the same.
1.41 1.27
1.67 1.63
0.006 0.001
IEQ-SF3
No one should have to live this way.
1.30
1.56
0.01
IEQ-SF4 IEQ-SF5
I can’t believe this has happened to me. Nothing will ever make up for what I have gone through.
1.30 0.89
1.55 1.32
0.009 0.001
Mean response
asked to indicate the frequency with which they experienced each of 9 symptoms that are considered in the diagnostic criteria for major depressive disorder (Spitzer, Williams, Kroenke, & the Patient Health Questionnaire Primary Care Study Group 1999). Ratings are made on a 4-point frequency scale with the endpoints (0) ‘not at all’ and (3) ‘everyday’. The scores range from 0 to 27 with higher scores representing more severe depressive symptoms. Reliability and validity of this measure have been demonstrated in various clinical populations (Gilbody, Richards, Brealey, & Hewitt, 2007; Huang, Chung, Kroenke, Delucchi, & Spitzer, 2006; Li, Friedman, Conwell, & Fiscella, 2007). Pain Severity The Pain Rating Index of McGill Pain Questionnaire Short – Form (MPQ-SF) was used to assess pain severity (Melzack, 1987). On this measure, participants are asked to rate their current pain experience according to 11 sensory and 4 affective pain descriptors. Ratings are made on a scale with the endpoints (0) none and (3) severe. A total score is generated by summing the participant’s responses to all 15 pain descriptors. The reliability and validity of the MPQ-SF have been demonstrated in several clinical and experimental studies (Burckhardt & Jones, 2005; Hood, Pulvers, Carrillo, Merchant, & Thomas, 2012). Participants also rated the severity of their pain on an 11-point Numerical Rating Scale (NRS) with the endpoints (0) no pain and (10) excruciating pain.
reported for the original version of the scale (alpha = 0.86) (Tait, Chibnall, & Krause, 1990). Procedure This research was approved by the Research Ethics Board of the McGill University Health Centre. Data were drawn from clinical files of clients referred for assessment at the Centre for Rehabilitation and Health, Toronto, Canada. Participants completed the IEQ-SF, the PHQ9, the MPQ-SF and the disability questionnaire as part of a standard assessment protocol. A subsample of participants (MSK = 36; MDD = 46) completed a 10-week risk-targeted activity re-integration intervention. Participants were enrolled in the treatment program if the results of a screening evaluation revealed evidence of a psychosocial risk profile. Perceived injustice was one of the psychosocial risk factors that were targeted by the intervention. Techniques used to target perceived injustice included validation, guided disclosure, thought monitoring and problem-solving, and goal setting. These techniques were incorporated within an activity re-integration program that included techniques such as structured activity scheduling and graduated resumption of discontinued activities. The primary purpose of the intervention was to reduce disability. Participants met with their clinician once per week for 10 weeks. Changes in IEQSF scores from pre- to post-treatment were used to conduct sensitivity analyses. The risk-targeted activity re-integration intervention in which participants were enrolled is described in more detail elsewhere (Sullivan, Adams, & Ellis, 2013).
Disability
Data Analysis
The measure of disability consisted of 5 items drawn from the Pain Disability Index (Tait, Chibnall, & Krause, 1990). For the purposes of this study, the instructional set was modified such that participants were asked to respond to items in relation to their health or mental health condition as opposed to their pain. Participants rated their level of disability in 5 domains of life (home responsibilities, social activities, recreational activities, occupational activities, self-care) on 11-point scales with the endpoints (0) no disability and (10) total disability. The Cronbach’s alpha for the modified version of the PDI used in this study (alpha = 0.81) was comparable to that
Means and standard deviations were computed on all study variables. T tests for independent variables were used to compare the MSK and MDD groups on all study variables. Cronbach’s alpha was computed on the IEQ-SF separately for the MSK and MDD groups. Correlational analyses were used to examine relations between the IEQ-SF and pain severity, depressive symptoms and disability. T tests for paired variables were conducted to examine the sensitivity of the IEQ-SF to treatment-related reductions in perceived injustice in participants who completed the 10-week risk-targeted activity re-integration program.
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Results Sample Characteristics Demographic information and means and standard deviations on study variables for the MSK and MDD groups are presented in Table 2. For the MSK sample, means and standard deviations on measures of pain severity and depression were comparable to those that have been reported in previous research on work-disabled individuals with pain (Dworkin, Turk, Revicki, Harding, Coyne, Peirce-Sandner et al., 2009; Melzack, 1987). Based on scores on the MPQ-SF and the PHQ-9, the MSK sample would be characterized as experiencing pain of moderate severity and depressive symptoms of mild severity. For the MDD sample, means and standard deviations on measures of depression and pain severity are also similar to those that have been reported in previous research (Lowe, Kroenke, Herzog, & Grafe, 2004). Based on scores on the PHQ-9 and MPQ-SF, the MDD sample would be characterized as experiencing depressive symptoms in the moderate-to-severe range, and pain symptoms in the mild range (Spitzer, et al., 1999). T tests for independent samples were used to compare the MSK and MDD groups on measures of symptom severity (e.g. pain severity, depression), disability, and the IEQ-SF (Table 2). As expected, participants in the MSK group rated their pain as more severe (MMPQ-SF = 17.2, SD = 10.7) than participants in the MDD group (MMPQ-SF = 11.0, SD = 8.6), t (173) = 4.2, p < 0.001. Participants in the MDD group reported more severe depressive symptoms (MPHQ-9 = 18.0, SD = 6.2) than participants in the MSK group (MPHQ-9 = 14.5, SD = 7.3), t (173) = −3.4, p < 0.001. Participants in the MDD group also scored higher on the IEQ-SF (MIEQ-SF = 7.2, SD = 2.1) than participants in the MSK group (MIEQ-SF = 6.6, SD = 2.8), t (173) = −4.0, p < 0.001. Table 2
In previous research, men with musculoskeletal pain have scored significantly higher on the original version of the IEQ than women (Sullivan et al., 2008). This pattern of findings was replicated in the present study. Men with musculoskeletal pain (M = 6.9, SD = 2.4) obtained significantly higher IEQ-SF scores than women (M = 5.2, SD = 3.1), t (85) = 2.7, p < 0.01. Men (M = 7.9, SD = 1.7) with depression also obtained higher IEQ-SF scores than women (M = 7.4, SD = 2.9), but the difference was not significant, t (85) = −0.84, ns. Reliability of the IEQ-SF Cronbach’s alpha was computed separately for the MSK and MDD groups. The internal consistency of the IEQ-SF was 0.82 for the MSK group and 0.75 for the MDD group. The item-total correlations for the MSK group ranged from 0.55 to 0.68. The item-total correlations for the MDD group ranged from 0.47 to 0.67. Test-retest reliability was examined by correlating the IEQ-SF scores at initial assessment to those obtained at the termination of the risk-targeted activity reintegration intervention. Test retest reliability was 0.82 for the MSK group and 0.72 for the MDD group. Construct Validity In previous research, scores on perceived injustice have been associated with heightened symptom severity and more pronounced disability. As presented in Table 3, the construct validity of the IEQ-SF was supported by significant correlations between the IEQ-SF and symptom severity and disability for both the MSK and MDD groups. The effect sizes for the relations between the IEQ-SF and symptom severity were in the moderate range for the MSK and MDD groups. The effect size for the relation between the IEQ-SF and disability was in the moderate range for the MSK group and in the modest range for the MDD group.
Sample characteristics
Variables
MSK N = 88
MDD N = 87
P
Age Sex (F/M) Duration (months) MPQ-SF Pain NRS (0–10) PHQ-9 DISAB IEQ-SF
47.5 (9.2) 49/38 17.4 (11.4) 17.2 (10.7) 5.49 (2.4) 14.5 (7.3) 33.0 (9.6) 6.1 (2.8)
46.9 (8.7) 58/29 16.7 (9.4) 11.0 (8.4) 3.83 (2.3) 18.0 (6.2) 34.6 (8.6) 7.7 (2.1)
ns ns ns 0.001 0.001 0.001 ns 0.001
N = 175 Duration duration of work disability, MPQ-SF McGill Pain Questionnaire – Short Form, Pain NRS Pain severity numerical rating scale, PHQ-9 Patient Health Questionnaire, DISAB Disability Index, IEQ-SF Injustice Experiences Questionnaire – Short Form
Table 3 Correlations among measures of perceived injustice, symptom severity and disability 1
2
3
4
5
1. IEQ-SF 2. MPQ-SF 3. Pain NRS
− 0.59** 0.45**
0.30* − 0.73**
0.32** 0.71** −
0.47** 0.43** 0.31*
0.23* 0.18 0.15
4. PHQ-9 5. Disab
0.44** 0.51**
0.56 ** 0.65**
0.41** 0.54**
− 0.60**
0.67** –
Correlations in the lower diagonal are from the MSK sample, correlations in the upper diagonal are from the MDD sample IEQ-SF Injustice Perceptions Questionnaire – Short Form, MPQ-SF McGill Pain Questionnaire – Short Form, Pain NRS Pain Numerical Rating Scale, PHQ-9 Patient Health Questionnaire, Disab Disability Index p =
