Journal of Clinical and Experimental Neuropsychology

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Difficulties with emotion regulation in multiple sclerosis: Links to executive function, mood, and quality of life Louise H. Phillips, Julie D. Henry, Eva Nouzova, Clare Cooper, Bogumila Radlak & Fiona Summers To cite this article: Louise H. Phillips, Julie D. Henry, Eva Nouzova, Clare Cooper, Bogumila Radlak & Fiona Summers (2014) Difficulties with emotion regulation in multiple sclerosis: Links to executive function, mood, and quality of life, Journal of Clinical and Experimental Neuropsychology, 36:8, 831-842, DOI: 10.1080/13803395.2014.946891 To link to this article: http://dx.doi.org/10.1080/13803395.2014.946891

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Date: 19 September 2017, At: 10:21

Journal of Clinical and Experimental Neuropsychology, 2014 Vol. 36, No. 8, 831–842, http://dx.doi.org/10.1080/13803395.2014.946891

Difficulties with emotion regulation in multiple sclerosis: Links to executive function, mood, and quality of life Louise H. Phillips1, Julie D. Henry2, Eva Nouzova1, Clare Cooper3, Bogumila Radlak1, and Fiona Summers4 1

School of Psychology, University of Aberdeen, Aberdeen, UK School of Psychology, University of Queensland, St Lucia, QLD, Australia 3 Aberdeen Health Psychology Group, University of Aberdeen, Health Science Building, Aberdeen, UK 4 Department of Neuropsychology, Aberdeen Royal Infirmary, Aberdeen, UK

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(Received 3 February 2014; accepted 15 July 2014) Introduction: Little is known about the influence of multiple sclerosis (MS) on the regulation of emotion. The current study tested whether people with MS report more emotion regulation difficulties than healthy controls. The relationship between emotion regulation and other important variables (mood, quality of life, and executive function) was explored. Mediation models were used to further understand the links between emotion regulation, depressed mood, and executive function in MS. Method: A total of 31 people with MS and 31 controls completed the Difficulties in Emotion Regulation Scales and measures of executive function (fluency and a go/no-go task), mood (Hospital Anxiety and Depression Scales), and a multidimensional assessment of quality of life (World Health Organization Quality of Life, brief version). Results: People with MS reported experiencing more difficulties in emotion regulation than controls. Mediation analyses indicated that depression mediated the emotion regulation difficulties in MS, while executive dysfunction did not. Difficulties in emotion regulation predicted poorer psychological and social quality of life in MS, independent of problems with executive function. Conclusions: People with MS experience difficulties in emotion regulation, which predict poorer quality of life. These results indicate that emotional control skills should be investigated in further detail when considering interventions to enhance well-being in MS. Keywords: Emotion regulation; Multiple sclerosis; Executive dysfunction; Mood; Quality of life.

Multiple sclerosis (MS) is one of the most common causes of neurological disability in younger and middle aged adults. While much is known of cognitive impairment in MS, such as slowed processing speed and reduced executive control (Kalmar, Gaudino, Moore, Halper, & Deluca, 2008), less is known about the nature of emotional problems accompanying the disease. MS is an inflammatory disorder with multiple areas of axonal demyelination, and these lesions often occur in the deep white matter of the frontal lobes (Brownell & Hughes, 1962). Frontalsubcortical circuits are implicated in the self-regulatory processes necessary to control cognition

(otherwise known as executive functions; Stuss & Alexander, 2007). Similar circuits may be involved in regulation of emotions (Ochsner & Gross, 2005). Many of those with MS experience difficulties in cognitive regulation, as measured by executive function tasks tapping inhibition, planning, or attentional control (e.g., Kalmar et al., 2008). This raises the question of whether the capacity to regulate emotions might be similarly disrupted. Emotion regulation includes awareness and appraisal of our own affective states, as well as the processes involved in understanding and influencing our emotions (Gross, Sheppes, & Urry, 2011). A high

We would like to thank Moira Cook for assisting with data collection. This research was funded by Tenovus Scotland [grant number G06/08 to L.H.P., J.D.H., and F.S]. Address correspondence to: Louise H. Phillips, School of Psychology, University of Aberdeen, William Guild Building, King’s College, Aberdeen, AB24 2UB, UK (E-mail: [email protected]).

© 2014 Taylor & Francis

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incidence of depression, irritability, and other mood problems has been clinically reported in MS for more than a century (Charcot, 1872; Cottrell & Wilson, 1926). Problems indicating a lack of emotional control, such as unusual feelings of euphoria, pathological laughing and crying, dramatic mood shifts, or a general feeling of emotional dyscontrol have been reported in MS (Harel, Barak, & Achiron, 2007). For example, Feinstein and Feinstein (2001) reported that 73% of people with MS endorsed subjective symptoms of emotion dyscontrol such as irritability or crying during the previous month. However, there was no comparison to a control group to discriminate whether these were abnormal frequencies. Around 10% of people with MS show pathological laughing and crying at psychiatric interview (Feinstein & Feinstein, 2001; Sá, 2008). The presence of pathological laughing and crying in MS is associated with poorer performance on executive function measures such as Stroop and verbal fluency (Feinstein, Connor, Gray, & Feinstein, 1999), indicating a possible link between failures of cognitive and emotional control in some people with MS. In a description of two case studies in MS, Asghar-Ali, Taber, Hurley, and Hayman (2004) report that symptoms such as labile affect could be associated with white matter hyperintensities disrupting connectivity within frontal-subcortical brain networks. Specific problems with emotion regulation are also linked to mood disorders such as depression (e.g., Garnefski & Kraaij, 2006) across a range of clinical and nonclinical groups. Ineffective emotion regulation strategies may lead to depressive symptoms, which in turn might cause further problems with emotion regulation. It is difficult to distinguish the interplay between emotion regulation and depression, although some longitudinal studies indicate that poor emotion regulation styles can predict later depression (e.g., Seymour, Chronis-Tuscano, Iwamoto, Kurdziel, & MacPherson, 2014). Mood abnormalities such as anxiety, depression, and stress response are widely reported in MS (Sá, 2008), but they have not previously been explored in relation to emotion regulation strategies. Clinical depression is estimated to affect around 50% of people with MS at some point, three times the prevalence in the normal population (Feinstein, 2011). Depression in MS is also linked to compromised neurocognitive function, particularly abnormalities in the frontal lobes and impaired executive function (Feinstein, 2011). In the current study we explore the links between emotion regulation, depression, and executive function in MS, using mediation analyses to test different models of the association between these constructs. To date, the studies of emotion regulation in MS described above have used clinical observation or

symptom report to assess neuropsychiatric disorder. However, to understand in more detail the nature of emotion regulation processes in MS it is important to look at specific aspects of emotional awareness, experience, and control, as assessed by standardized assessments. Phillips et al. (2009) investigated MS participants’ report of suppression and reappraisal strategies to control affect using the Emotion Regulation Questionnaire (Gross & John, 2003). There was no control comparison group in that study, but results indicated that failure to use reappraisal as a method to regulate emotions correlated with poorer self-assessed quality of life. However, it remains important to also understand the effects of MS on a broader range of emotion regulation strategies and to compare those with MS to a healthy control group. In the current study we address these gaps in the literature. It is of particular interest to establish whether difficulties with emotion regulation in MS are associated with impairments in executive function. As noted previously, neuropsychological theories emphasize possible overlap in brain regions involved in the regulation of both cognitive and emotional functions (e.g., Ochsner, Bunge, Gross, & Gabrieli, 2002). Performance on some executive function measures have been shown to relate to indices of emotion regulation in a sample of older people including those with and without dementia (Gyurak et al., 2009). Gyurak et al. (2009) concluded that verbal fluency measures of executive function, which tap into complex processes of monitoring and evaluation, assess self-control mechanisms that overlap with those needed in emotion regulation. There is increasing evidence from studies with healthy participants of links between “cold” cognitive executive control functions and “hot” emotion regulation processes (Hofmann, Schmeichel, & Baddeley, 2012). It is important to understand more about the effects of MS on emotional regulation, because difficulties with emotion awareness and control have been shown to predict well-being in a range of healthy and clinical populations (Gross & John, 2003; Phillips, Henry, Hosie, & Milne, 2006; Sunga et al., 2012; Van Middendorp et al., 2005). Better regulation of emotion predicts high life satisfaction, protects against psychopathology, enhances effectiveness at work, and underlies the ability to form sustainable relationships in adulthood (for a review see Gross & Munoz, 1995). Our previous research indicates that failure to use cognitive reappraisal to regulate emotion predicts impaired quality of life in people with MS (Phillips et al., 2009) but it would be useful to investigate a broader range of emotion regulation strategies. Motor,

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EMOTION REGULATION DIFFICULTIES IN MS

perceptual, and cognitive problems in MS can cause difficulties in everyday functioning. But problems with emotional skills in MS, such as emotion perception and emotion regulation, predict quality of life independently of disease severity and cognitive functioning (Phillips et al., 2009, 2011). Thus, while most measures of disease severity in MS focus mainly on physical symptoms of the disease, there is a clear need to understand more about emotional and social skills to address fully the quality of life of people with MS. One aim of the current research is therefore to look at connections between emotion regulation difficulties and measures of quality of life. An important strength of the current research is the use of the Difficulties in Emotion Regulation Scale (Gratz & Roemer, 2004) to assess emotion regulation. This measure includes multiple subscales designed to tap into a range of emotion regulation processes, including awareness and understanding of the emotion experienced, acceptance of the emotion, an ability to control impulsive behavior in the context of negative emotion, and an ability to use flexible strategies to modulate emotional experience according to the situation demands. These different aspects of emotion awareness and control are likely to be important in well-being, mood maintenance, and social interactions.

Aims The current study tested the following predictions. (a) People with MS will report more difficulties with emotion regulation than matched healthy controls. (b) People with MS who report the greatest difficulties with emotion regulation will also experience lower quality of life and increased levels of anxiety and depression. (c) Measures of executive function will be related to difficulties in emotion regulation. To further understand the links between emotion regulation, depressed mood, and executive function in MS, three different mediation models were tested. We also used regression analysis to explore whether emotion regulation and executive function measures together could predict a significant portion of the variance in quality of life in MS. METHOD Participants A total of 32 people with MS (8 male) and 32 healthy age- and education-matched controls (6 male) completed this study. All of the participants

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were white British, reflecting the relatively homogenous ethnic characteristics of MS patients in the local region. Subsequently, one participant with MS and one control were excluded from analyses due to performance 3 standard deviations outside of each respective group norm on the total scores of the Difficulties in Emotion Regulation questionnaire. We followed the advice of Judd and Sadler (2003) that for correlational analyses in clinical samples, it is usually best to omit extreme outlying values, but note that the conclusions reported are not altered if these participants are included in analysis. MS participants were recruited through the Grampian MS Research Database. All met McDonald criteria for MS (McDonald et al., 2001), as assessed by a neurologist. The mean time since clinical diagnosis was 7.87 years (SD = 5.48), and 27 of the participants had the relapsing-remitting form of the illness, while two had the primary and three the secondary progressive form, as ascertained by a neurologist. The majority of relapsingremitting patients were taking disease-modifying medication (primarily beta interferon), while those with progressive disease variants were not. In total 23 of the participants with MS were taking medication, and t tests comparing those with and without medication showed no differences on any of the measures in the current study. Specifically, for our key variable (total score on the Difficulties in Emotion Regulation Scale) there was no effect of medication, t(29) = 1.44, d = 0.53. None of the participants was undergoing a relapse during testing. Participants’ mean score on a researcher-rated variant of the Disease Steps measure of MS severity (Hohol, Orav, & Weiner, 1995) was 2.22 (SD = 1.68), with scores spanning the maximum range on this measure from 0 (normal) to 6 (confined to wheelchair). The Disease Steps correlates strongly (r = .96) with the physician-encoded Kurtzke Expanded Disability Status Scale (EDSS; Hohol et al., 1995; Kurtzke, 1983). Control participants were recruited from the general community via advertisements and word of mouth. For descriptive demographic information see Table 1. The mean age did not differ significantly between the two groups, t(63) = 0.17, Cohen’s d = 0.04. The two groups also did not significantly differ in years of education, t(63) = 1.61, d = 0.40, or gender ratio, χ2 = 0.624, Φ = 0.10. Grampian National Health Service Local Research Ethics Committee granted ethical approval, and all participants provided informed consent. Exclusion criteria for both groups were: (a) history of neurological disease (other than MS for the clinical group); (b) history of major psychiatric illness; (c) presence or premorbid history of

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PHILLIPS ET AL. TABLE 1 Descriptive statistics for control and MS group on all measures

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Variable Age (years) Education (years) DERSa Nonacceptance Goals Impulse Awareness Strategies Clarity Total HADS Anxiety Depression Quality of life Physical Psychological Social Environmental Executive function measures Letter fluency SART go/no-go

Controls (n = 31)

MS (n = 31)

M

SD

M

SD

44.47 16.59

9.72 3.69

43.97 15.45

9.31 3.26

1.92 2.47 1.75 3.41 1.81 2.40 13.76

0.68 0.43 0.26 0.80 0.33 0.30 1.29

2.30 2.55 1.88 3.32 1.98 2.75 14.77

0.83 0.68 0.37 0.52 0.47 0.46 1.81

5.16 2.13

2.23 2.01

5.55 4.81

3.85 4.06

31.34 22.66 12.38 33.09

3.17 2.93 1.56 2.75

23.77 20.77 11.35 31.19

5.52 4.11 2.30 4.35

49.50 0.75

13.60 0.88

41.19 2.29

16.30 2.87

Note. MS = multiple sclerosis; DERS = Difficulties in Emotion Regulation Scale; SART = Sustained Attention to Response Test; HADS = Hospital Anxiety and Depression Scales. a Note that higher scores on the DERS indicate greater levels of difficulty with emotion regulation.

alcohol or drug abuse; (d) severe motor disturbances, current optic neuritis, or other visual deficit that would interfere with testing. Measures Emotion regulation Problems with emotion regulation were assessed using the Difficulties in Emotion Regulation Scale (DERS; Gratz & Roemer, 2004). The DERS is a 36-item self-report questionnaire designed to assess multiple aspects of emotion regulation. The scale provides a total score as well as six subscale scores measuring difficulties in aspects of emotion regulation, including: acceptance of emotions (“When I’m upset, I become embarrassed for feeling that way”), ability to engage in goal-directed behavior when distressed (“When I’m upset, I have difficulty getting things done”), impulse control (“When I’m upset, I feel out of control”), awareness of emotions (“I pay attention to how I feel”), access to strategies for regulation (“When I’m upset, I believe that there is nothing I can do to make myself feel better”), and clarity of emotions

(“I am confused about how I feel”). Participants indicate how often each item applies to themselves on a 5-point scale ranging from “almost never” to “almost always”. Scores are coded such that higher scores indicate greater difficulties in emotion regulation. DERS has high internal consistency, α = .93 (Gratz & Roemer, 2004), and the six scales form replicable factors that have good evidence of external validity (Weinberg & Klonsky, 2009), including prediction of behavioral assessments of emotion regulation (Vasilev, Crowell, Beauchaine, Mead, & Gatzke-Kopp, 2009). Executive function measures Fluency. Each participant completed the FAS letter fluency task (words beginning with F, A, and S for one minute each), which is known to tap both speed of processing and executive functioning and to be amongst the most sensitive neuropsychological measures to cognitive impairment in MS (Henry & Beatty, 2006). Raw scores (total number of words produced for all three letters) are reported here. Sustained Attention to Response Task. The Sustained Attention to Response Task (SART; Robertson, Manly, Andrade, Baddeley, & Yiend, 1997) is a variant of the go/no-go task measuring attentional control and inhibitory skill. Previous research indicates that MS causes poorer performance on similar go/no-go tasks (Claros-Salinas et al., 2010). Participants completed 100 trials. For each a single digit was displayed on a computer screen. On the appearance of a number, the task was to press the spacebar as quickly as possible and say the digit out loud, except when the number was 3 or 9 (20% of trials), where the instruction was to withhold making any response. Performance was recorded in terms of the number of 3 or 9 trials where errors were made. Quality of life Self-rated quality of life was assessed using the World Health Organization Quality of Life questionnaire (WHOQoL-BREF; Skevington, Lofty, & O’Connell, 2004). Participants completed this measure, which required them to rate various aspects of their quality of life (QoL) over the previous two weeks. Four distinct domains of QoL (physical health, psychological well-being, social relationships, and functioning in the environment) were assessed using 24 questions. Higher scores represent better perceived QoL, with scores calculated

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EMOTION REGULATION DIFFICULTIES IN MS

on a 0–100 scale. The WHOQoL-BREF domain scores have good construct and discriminant validity, as well as acceptable reliability and sensitivity to health improvements (Skevington et al., 2004). The WHOQoL-BREF is recommended as a measure of quality of life in MS (Wynia, Middel, van Dijk, De Keyser, & Reijneveld, 2008), because it is sensitive to physical disabilities, activity limitations, social participation restrictions, and difficulties in functioning in everyday environments. The WHOQoL-BREF has been shown to have good validity in MS samples in terms of correlations with depression, disability, and caregiver assessments of QoL (Alshubaili, Awadalla, Ohaeri, & Mabrouk, 2007). Mood Participants also completed the Hospital Anxiety and Depression scales (HADS; Zigmond & Snaith, 1983) to assess negative mood. This 14item measure includes seven items that index depression and seven that index anxiety. The HADS has good reliability and validity (see Bjelland, Dahl, Haug, & Neckelmann, 2002, for a review) and is appropriate for use in MS (e.g., Knoop, van Kessel, & Moss-Morris, 2012). Procedure Participants completed the HADS at the beginning of the testing session, followed by the executive function tasks (fluency, SART), and the DERS and WHOQoL-BREF measures at the end. Other tasks were also carried out, which are not further discussed here. Analysis Group differences in the multiple subscales of the DERS, HADS, and WHO-QoL were investigated by separate mixed design analyses of variance (ANOVAs), followed up with t tests to specify group differences in individual subscales where an interaction was found. Group differences in the executive function tasks were examined by t tests, using a significance level of p < .01 to allow for multiple comparisons. Relationships of DERS scores with other measures were explored using Pearson’s correlations, again using a significance level of p < .01 to allow for multiple comparisons. Mediation analysis was carried out to look at whether group differences in DERS scores were mediated by depression or executive function, with bootstrapping procedures to test the

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significance of the mediation effects. Final hierarchical regression analyses explored whether problems with emotion regulation predicted quality of life in MS independently of executive dysfunction.

RESULTS Group differences Table 1 provides a summary of descriptive information for each of the dependent measures (emotion regulation, mood, quality of life, and cognitive performance). A 2 × 6 mixed design analysis ANOVA varying group (control or MS) and DERS subscale (nonacceptance, goals, impulse, awareness, strategies, or clarity) was carried out. There was a main effect of group, F(1, 59) = 6.94, p < .05, ηp2 = .105, indicating that MS participants reported more difficulties with emotion regulation than did control participants, with a small to medium effect size (see Cohen, 1988). There was a main effect of subscale, F(2.54, 149.69) = 73.24, p < .001, ηp2 = .554, but no interaction between group and DERS subtest type, F(2.54, 149.69) = 1.76, ηp2 = .029. Because there was no interaction between group and subscale, subsequent analyses are based on DERS total score. To look at the effects of MS on mood a Group (control or MS) × HADS Subscale (Anxiety or Depression) mixed design ANOVA revealed a main effect of group, F(1, 61) = 4.77, p < .05, ηp2 = .072, and a main effect of HADS subscale, F(1, 61) = 25.76, p < .01, ηp2 = .297. The analysis also revealed an interaction between group and HADS subscale, F(1, 61) = 9.48; p < .01, ηp2 = .135. Subsequent t tests showed that depression scores were significantly higher in the MS group than in the control group, t(61) = 3.45, p < .01, d = 0.88, indicating a large effect size, but no difference was found between the MS group and controls on the HADS anxiety scores, t(61) = 0.37, d = 0.09. For the assessment of quality of life, a Group (control or MS) × Quality of Life Domain (physical, psychological, social, or environmental) mixed design ANOVA was undertaken. Participants with MS reported lower quality of life than controls, F(1, 61) = 20.95, p < .01, ηp2 = .256. There was a main effect of the quality of life category, F(2.29, 139.56) = 609.89, p < .01, ηp2 = .919, qualified by an interaction between group and category, F(2.29, 139.56) = 20.45, p < .01, ηp2 = .251. Independent samples t tests revealed a significant difference between the groups with a large effect size for physical quality of life, t(61) = 6.64, p < .01, d = 1.70. For the other domains, the group differences did not meet the more stringent p < .01 level of

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significance specified above, but showed moderate effects at conventional levels of significance: psychological, t(61) = 2.09, p < .05, d = 0.54; social, t(61) = 2.02, p < .05, d = 0.52; environmental, t(61) = 2.07, p < .05, d = 0.53. In terms of the executive function tasks carried out, the group difference in FAS letter fluency approached significance, t(61) = 2.20, p < .05, d = 0.56, with the MS group performing worse than the controls. There was a significant group difference indicating poorer performance by MS than by control participants on the SART go/nogo task, t(61) = 2.87, p < .01, d = 0.73.

Relationships between DERS and other variables Correlations for both groups (controls and MS) between DERS total scores and mood, quality of life, and executive function scores are shown in Table 2. For the control group there were no significant correlations between the total DERS score and other administered assessments. In contrast, for the MS participants there were significant correlations between DERS total score and both HADS Anxiety and Depression scores, indicating medium to large effect sizes (Cohen, 1988). DERS scores significantly correlated with social quality of life, and the correlations with psychological and environmental quality of life approached significance using the more stringent p < .01 criteria. All of these relationships had medium effect sizes. The correlation between DERS score and letter

TABLE 2 Correlations between total DERS score and mood, quality of life, and executive function scores for both control and MS groups Correlation HADS Anxiety Depression Quality of life Physical Psychological Social Environmental Executive function measures Fluency SART go/no-go

Controls

MS

.029 .031

.550* .456*

–.091 .105 .200 .343

–.344 –.422† –.482* –.408†

.092 –.116

–.445† .302

Note. MS = multiple sclerosis; SART = Sustained Attention to Response Test; HADS = Hospital Anxiety and Depression Scales. † p < .05. *p < .01.

fluency approached significance and was of medium effect size. To better understand the effects of MS on emotion regulation, executive function, and depression and their interrelations, a series of mediation models were tested. In mediation analysis a series of regressions are carried out to test whether the association between the predictor variable (group) and the dependent variable (DERS total) is significantly mediated by a third variable (either depression or executive function); see Figure 1a. An initial regression examines the relationship between the predictor and mediator variable through a linear regression. The second step confirms the relationship between the predictor variable and the dependent variable through linear regression. The final regression analysis simultaneously enters the mediator and predictor variables to explain variance in the dependent variable. Once the regression models have been run, the significance of any mediation effect can be tested using bootstrap procedures (Hayes, n.d.; Preacher & Hayes, 2004, 2008 for the macros used, and Figure 1a for a path diagram). In Model 1, executive function (FAS fluency) and depression were tested as mediators of group effects (MS vs. control) on DERS emotion regulation scores (see Figure 1b and Table 3). This analysis revealed that depression scores were a significant mediator of the MS effects on DERS scores, while fluency scores were not. In Model 2, FAS fluency and DERS emotion regulation scores were considered as mediators for group differences in depression. Fluency scores were not a significant mediator, while emotion regulation scores were (see Figure 2a and Table 3). Finally, in Model 3, group differences in FAS fluency were considered in relation to possible mediating effects from emotion regulation and depression. Neither emotion variable was a significant mediator (see Figure 2b and Table 3). These mediation models indicate that depression was a significant mediator of MS effects on emotion regulation and also that emotion regulation significantly mediated the effects of MS on depression. In contrast, neither emotion regulation nor depression could explain MS effects on FAS fluency. In order to explore whether DERS scores predicted variance in quality of life in addition to any cognitive problems experienced in MS, separate linear regression analyses were carried out in the MS sample only for each WHO-QoL domain (see Table 4). Physical aspects of quality of life were not predicted by executive function scores or emotion regulation difficulties. In contrast, a greater number of emotion regulation problems predicted poorer psychological quality of life. Both emotion

EMOTION REGULATION DIFFICULTIES IN MS

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(a) Diagram of paths in mediation model

Mediator 1 (M1) Effect of IV on M1

Direct effect of M1 on DV Total effect of IV on DV

Independent Variable (IV)

(Direct effect of IV on DV accounting for M1 & M2)

Dependent Variable (DV)

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Direct effect of M2 on DV Effect of IV on M2 Mediator 2 (M2)

(b) Model 1 Fluency –7.452†

–0.020 1.007 *

Group

DERS (0.428)

2.645 **

0.164 ** HADS-D

Figure 1. (a) Mediation model tested in the current research (based on Preacher & Hayes, 2008). DERS = Difficulties in Emotion Regulation Scale; HADS–D = Hospital Anxiety and Depression Scales–Depression; IV = independent variable; DV = dependent variable. The model reports the effect of the independent variable (in this case group: control or multiple sclerosis, MS) on the mediators and the total effect of group on the dependent variable. The key parameter in determining the mediation effect is the direct effect of group once the mediators have been taken into account (the central figure in parentheses). Also important are the direct effects of the potential mediators on the dependent variables (on the right-hand side of the figure). The significance of the mediation effect is determined by a bootstrapping procedure; see Table 3 for results. (b) Model 1: Mediation effects of fluency and depression on group differences in emotion regulation scores. All figures are uncorrected path coefficients. The results indicate that the association between group and DERS scores was reduced when the mediators were taken into account (compare the figures above and below the central arrow). Bootstrapping indicated that HADS–D was a significant mediator of the relationship between group and DERS scores, while fluency was not (see Table 3 for details). Note: †p = .05. *p < .05. **p < .01.

regulation difficulties and SART inhibition scores predicted social quality of life. There were no significant predictors of environmental quality of life. DISCUSSION Multiple sclerosis was associated with greater difficulties in emotion regulation compared to scores

in a matched control group. There was a moderate effect of MS on emotion regulation as measured by the DERS, but no interaction between group and DERS subscale, indicating that the effects of MS were similar on all aspects of emotion regulation. MS was also linked to higher levels of depression, although not anxiety (note that a similar pattern is reported in Rendell et al., 2012), and lower

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TABLE 3 Tests of mediation effects shown in Figures 1 and 2 explaining group differences between people with MS and controls in emotion regulation, depression, and executive function BCBCI Model 1 2 3

DV DERS HADS–D FAS

BCBC1

Mediator 1

Lower

Higher

Mediator 2

Lower

Higher

FAS FAS DERS

–0.031 –0.790 –6.093

0.550 0.387 0.380

HADS–D* DERS* HADS–D

0.074 0.089 –3.110

1.031 2.001 5.316

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Note. Significant mediation effects (at p < .05) are present where lower and upper confidence intervals of the bootstrap values do not include zero (see Preacher & Hayes, 2004, 2008). MS = multiple sclerosis; DERS = Difficulties in Emotion Regulation Scale; HADS = Hospital Anxiety and Depression Scales; D = Depression; DV = dependent variable; BCBCI: bias corrected bootstrap confidence interval with 5000 resamples. *Significant mediation effect at p < .05.

(a) Model 2

Fluency –7.452†

0.007 2.645 **

Group

HADS-D (1.987 *)

1.007 *

0.708 ** DERS

(b) Model 3 HADS-D 2.645 **

0.168 –7.452†

Group

FAS (–5.953)

1.007 *

–1.931 DERS

Figure 2. (a) Model 2: Mediation effects of fluency and emotion regulation on group differences in depression. DERS = Difficulties in Emotion Regulation Scale; HADS–D = Hospital Anxiety and Depression Scales–Depression. All figures are uncorrected path coefficients. The results indicate that the association between group and depression scores was reduced when the mediators were taken into account (compare the figures above and below the central arrow). Bootstrapping indicated that DERS was a significant mediator of the relationship between group and depression scores, while fluency was not (see Table 3 for details). (b) Model 3: Mediation effects of emotion regulation and depression on group differences in fluency. There was no significant mediation effect in this model (see Table 3 for details). Note: †p = .05. *p < .05. **p < .01.

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TABLE 4 Regression statistics within the MS sample Dependent variable: WHOQoL category

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Predictors Fluency β t Part correlation Tolerance SART β t Part correlation Tolerance DERS total β t Part correlation Tolerance F(3, 27) Total R2

Physical

Psychological

Social

Environmental

.085 –0.437 –.078 .842

–.062 –0.343 –.057 .842

–.020 –0.120 –.018 .842

.108 0.572 .099 .842

–.103 –0.543 –.097 .892

–.314 –1.797 –.296 .892

–.399 –2.481* –.377 .892

.108 –0.642 –.111 .892

–.345 –1.732 –.311 .810

–.358 –2.015* –.321 .810

–.368 –2.180* –.332 .810

–.332 –1.725 –.298 .810

1.37

3.23*

5.41**

2.14

.266

.375

.132

.192

Note. Separate linear regressions were carried out for each domain of quality of life as a dependent variable. DERS emotion regulation scores and executive function measures (SART and fluency) were entered as predictors. MS = multiple sclerosis; DERS = Difficulties in Emotion Regulation Scale; SART = Sustained Attention to Response Test; WHOQoL = World Health Organization Quality of Life questionnaire. *p < .05. **p < .01.

self-rated quality of life. In relation to executive function, people with MS tended to perform worse than controls on both the letter fluency and the SART inhibition test. While executive function deficits and emotion regulation problems have previously been reported in MS (Henry & Beatty, 2006; Phillips et al., 2009), there is little evidence to determine whether these two domains are correlated. MS is a disease that has hugely varied effects on physical, cognitive, and emotional function, and so it is important to understand how the different types of problem might overlap. In the current sample of MS participants, there was some evidence suggesting a possible relationship between executive dysfunction and difficulties in emotion regulation. Correlations with total DERS scores approached significance for the letter fluency task, which imposes particular demands on cognitive flexibility, but not for the SART test, which depends more on behavioral inhibition. Relatively few previous studies have looked at the relationship between executive function and emotion regulation in any sample. Gyurak et al. (2009) looked at the relationship between executive functions (updating, inhibition, switching, and flexibility) and behavioral emotion regulation in a sample including healthy older adults and those with different types of dementia. They reported that greater difficulty in suppressing emotional

display was related to fluency but not the other assessments of executive function, and they concluded that attentional flexibility was the most important executive function in predicting emotion regulation difficulties. In our study we had a different sample, and a much broader self-rated assessment of emotion regulation, but we also found that fluency performance was related to difficulties in regulating emotions. Fluency was also found to be important in a study by Feinstein et al. (1999), who found that people with MS who had serious emotion dyscontrol (pathological levels of laughing and crying) were impaired on letter fluency compared to a group of MS participants with normal emotional control. These findings, taken together with the current results, indicate that attentional flexibility may be important in emotion regulation problems in MS. It would be interesting to explore this in more detail in future studies with a more detailed assessment of a range of different executive functions and behavioral measures of emotion regulation. This study also explored the link between emotion regulation and quality of life. Difficulties with emotion regulation were related to quality of life ratings in the MS group. This fits with growing evidence of the link between emotion regulation abilities and well-being (John & Gross, 2004). In a recent study, Cooper, Phillips, Johnston, MacLeod, and Whyte (in press), we found that

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stroke survivors were significantly impaired in several domains of emotion regulation: impulse control, awareness of feelings, and use of strategies to regulate emotions. These difficulties with emotion regulation in the stroke sample significantly predicted psychological and social quality of life. Difficulties in regulating anger also predicted multiple domains of well-being in a sample of 286 healthy adult participants across the age range (Phillips et al., 2006). Further, there is evidence that behavioral measures of emotion regulation (startle response and controlling the outward display of emotion) relate to well-being in healthy younger adults (Côté, Gyurak, & Levenson, 2010). To explore whether emotion regulation and cognitive function contributed separately to quality of life in the MS sample, regression analyses were carried out. Emotion regulation predicted psychological and social domains of quality of life in MS, similar results to a previous study in which we looked specifically at the use of reappraisal to regulate emotion (Phillips et al., 2009). In that previous study we also found that self-rated measures of attentional lapses predicted all domains of quality of life. In the current sample, fluency scores did not predict any aspect of quality of life, while SART inhibition scores predicted social well-being. It would be useful in future research to have additional measures of emotion regulation and executive function in a larger sample of participants with MS to establish in more detail which aspects of cognitive and affective functioning are most related to quality of life. DERS scores were related to both depression and anxiety levels in the current sample. Difficulties in emotion regulation have also been conceptually and empirically related to the experience of negative mood in other samples (Berking & Wupperman, 2012; Staples & Mohlman, 2012; Weinberg & Klonsky, 2009). To further explore the relationships between emotion regulation, depression, and executive function in MS a series of mediation models were tested. The effects of MS on emotion regulation scores were mediated by depression ratings, but not executive function. This indicates that difficulties with executive function are unlikely to be the primary cause of problems with emotion regulation. Also, low mood may be important in poor emotion regulation. A further mediation model also indicated that executive function did not mediate group differences in depression, while emotion regulation scores did. This supports a bidirectional influence of emotion regulation difficulties on depression and vice versa. Future studies should use longitudinal techniques to explore the temporal nature of this relationship, perhaps through the use

of experience sampling methods. Longitudinal methods might also help to tease apart how coping with intense emotional issues raised by living with a lifelong degenerative condition relate to emotion regulation. To address this issue it would also be useful to compare links between illness perception and emotion regulation in those with MS to a sample of people with a non-neurological degenerative conditions. A final mediation model indicated that neither emotion variable (regulation or depression) mediated MS effects on executive function scores. It should be noted that this was likely a highfunctioning sample of people with MS, with only five participants with MS reporting depression scores on the HADS of 8 or above, the recommended cutoff score for clinical levels of depression (Bjelland et al., 2002). It would be useful in future studies to select samples of people with MS who have a wider range of cognitive difficulties or mood disorder; however, these participants are difficult to recruit. In this study we cannot determine whether difficulties in emotion regulation in MS might be caused by neural changes associated with the disease, and it would be useful in future studies to include brain imaging data. Other types of neurological condition, such as stroke, also cause difficulties with emotion regulation (e.g., Cooper et al., in press); however, it would be useful to know whether coping with non-neurological long-term health conditions might cause difficulties in emotion regulation. To conclude, current results indicate that people with MS have difficulties with emotion regulation compared to demographically matched controls. These problems in control of emotions were related to depression, anxiety, and a measure of executive attentional control (letter fluency). Mediation models indicated interlinked associations between depression and emotion regulation in MS, while executive function did not mediate the effects of MS on emotion regulation. Difficulties in emotion regulation predicted poorer quality of life, indicating that it is important to consider emotional skills when considering how to enhance well-being in MS.

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