The relationship between trait mindfulness, personality and psychological distress: A revised reinforcement sensitivity theory perspective

Personality and Individual Differences 99 (2016) 100–105

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The relationship between trait mindfulness, personality and psychological distress: A revised reinforcement sensitivity theory perspective Paul H. Harnett a,⁎, Natasha Reid b, Natalie J. Loxton b,c, Nick Lee a a b c

The University of Queensland, Australia Griffith University, Australia Centre for Youth Substance Abuse Research, The University of Queensland, Australia

a r t i c l e

i n f o

Article history: Received 22 July 2015 Received in revised form 20 April 2016 Accepted 25 April 2016 Available online xxxx Keywords: Personality Mindfulness Psychological distress

a b s t r a c t Interest in the application of mindfulness-based intervention for the treatment of psychological disorders and promotion of wellbeing has grown exponentially in recent years. Mindfulness-based interventions have been found to be beneficial for treatment of various forms of psychopathology as well as improve psychological wellbeing and enhance physical health. Little research has investigated for whom and under what conditions training people to use mindfulness-based therapeutic techniques is most effective. Recent studies have found evidence that individual differences in personality traits are associated with mindfulness. For example, neuroticism has been found to be negatively associated with mindfulness. These associations raise the possibility that individual differences in personality may potentially moderate the effectiveness of mindfulness-based interventions. In the present study we draw on Gray's revised Reinforcement Sensitivity Theory (r-RST) to examine relationships between personality traits, mindfulness and psychological distress. We found that the Flight, Fight, Freeze system mediated the relationship between trait mindfulness and psychological distress, while trait mindfulness moderated the relationship between the Flight, Fight, Freeze system and psychological distress. Both results are consistent with the suggestion that acquiring the skills from learning and practicing mindfulness techniques is potentially useful, particularly for threat-sensitive individuals with low to moderate levels of trait mindfulness. © 2016 Elsevier Ltd. All rights reserved.

1. Introduction Interest in the Eastern philosophical concept of mindfulness for the treatment of psychological disorders and promotion of wellbeing is rapidly increasing. A large body of research has documented the effectiveness of mindfulness-based interventions for a range of clinical disorders (Bowen et al., 2014; Khoury et al., 2013; Masuda & Hill, 2013). In nonclinical samples, mindfulness-based interventions have been associated with improved attention and memory (Chiesa, Calati, & Serretti, 2011), psychological wellbeing and physical health (Carlson, Speca, Faris, & Patel, 2007; Davidson et al., 2003; Keng, Smoski, & Robins, 2011). Mindfulness appears beneficial for individuals across the lifespan from young children (Flook, Goldberg, Pinger, & Davidson, 2015) to older adults (Moynihan et al., 2013). Despite this large body of research, little research has investigated for whom, and under what conditions, mindfulness-based therapeutic techniques is most effective. Keng et al. (2011) reviewed preliminary evidence suggesting that the effectiveness of mindfulness-based ⁎ Corresponding author at: School of Psychology, The University of Queensland, Brisbane Qld 4072, Australia. E-mail address: [email protected] (P.H. Harnett).

http://dx.doi.org/10.1016/j.paid.2016.04.085 0191-8869/© 2016 Elsevier Ltd. All rights reserved.

interventions may vary as a function of individual differences. For example, one study found that participants who reported an insecure attachment style derived greater benefit from the Mindfulness-based Stress Reduction (MBSR) program than participants with a secure attachment (Cordon, Brown, & Gibson, 2009). In another study mindfulness moderated the effects of MBSR, with higher mindfulness resulting in greater improvements (Shapiro, Brown, Thoresen, & Plante, 2011). Recent studies have found associations between mindfulness and personality traits. For example, neuroticism and impulsivity were found to be negatively associated, and conscientiousness positively associated, with mindfulness (Fetterman, Robinson, Ode, & Gordon, 2010; Giluk, 2009; Lattimore, Fisher, & Malinowski, 2011). While suggesting that personality may moderate the effectiveness of mindfulness-based interventions, these studies were not theoreticallyderived by established models of personality. In the present study we draw on Gray's revised Reinforcement Sensitivity Theory (r-RST) as the three biologically-based sub-systems postulated by r-RST have been found to be associated with both psychological distress and wellbeing (Erdle & Rushton, 2010; Harnett, Loxton, & Jackson, 2013; Jovanovic, 2011). The first of the r-RST sub-systems – the Behavioral Approach System (BAS) – mediates behavioral approach towards signals of reward. High BAS is associated with positive affect, while

P.H. Harnett et al. / Personality and Individual Differences 99 (2016) 100–105

low levels of BAS activity are associated with depression (Harnett et al., 2013). The second sub-system – the Flight, Fight, Freeze System (FFFS) – mediates the behavioral avoidance of punishment or threat. FFFS activity elicits fear responses and is an aetiological factor in phobia and panic disorders (Gray & McNaughton, 2000). The third subsystem – the Behavioral Inhibition System (BIS) – operates to resolve conflict when both the BAS and FFFS systems are activated; as would occur when signals of possible reward coexist with possible threat. BIS leads behaviorally to a cautious approach response in order to resolve the conflict. The subjective experience of BIS activation is anxiety and thus implicated in the etiology of anxiety disorders. A small number of studies have investigated the relationship between mindfulness and psychological distress and wellbeing from the perspective of RST. These studies have either viewed personality traits as a mediator of the relationship between mindfulness and psychological functioning (wellbeing and psychological distress) or viewed trait mindfulness as a moderator of the relationship between personality and psychological functioning. Sauer, Walach, and Kohls (2011) pointed out that the Buddhist concept of “sankhara” refers to an aversion to the present state of affairs triggering defensive emotional and behavioral responses (see De Silva, 2001). The authors noted the similarity between the sankhara process and the function of the BIS, and argued that mindfulness can be seen as a mechanism to weaken the sankhara process, or in r-RST terms, BIS activity. Their data confirmed BIS (conceptualized as a combination of the BIS and FFS in line with the original RST, o-RST; Gray, 1982) mediated the relationship between mindfulness and wellbeing in a non-clinical sample. Further, a sub-group of experienced mindfulness practitioners reported higher levels of mindfulness and wellbeing, and lower BIS scores compared to non-practitioners. Sauer et al. (2011) concluded that practicing mindfulness can reduce sensitivity to punishment. However, it is debatable whether the practice of mindfulness would have changed the sensitivity of the BIS system at the neurological level or provided the practitioners of mindfulness strategies to mitigate the effects of high BIS sensitivity. Self-report measures of BIS measure the output of the system (avoidance motivation and the subjective experience of anxiety and fear) not the sensitivity of the system itself. Thus, if people learn strategies to manage negative affect they would very likely reported lower scores on measures of BIS even if the sensitivity of the neurological structures underlying BIS remained unchanged. Hamill, Pickett, Amsbaugh, and Aho (2015) argued that emotion regulation strategies can potentially mitigate the effects of BIS activity without changing the sensitivity of the BIS, implying that mindfulness maybe a moderator of the relationship between BIS sensitivity and psychological distress. Hamill et al. (2015) confirmed that facets of mindfulness moderated the relationship between BIS sensitivity and psychological distress. Reese, Zielinski, and Veilleux (2015) predicted that facets of mindfulness would mediate, rather than moderate, the relationship between BIS sensitivity and emotion dysregulation as a result of individuals with high threat sensitivity underutilizing mindfulness skills. Their results supported this hypothesis but it was not made clear why high BIS activity should lead to underutilization of mindfulness skills. They did not test a moderation model and psychological distress was not assessed in this study. The primary aim of the present study was to add to the literature by further investigating the relationships between mindfulness, dimensions of personality and psychological distress. The first specific aim was to establish whether trait mindfulness predicts psychological functioning over and above personality variables. The second aim was to test both the moderation and mediation models tested in previous studies as described above. The specific hypotheses tested were 1) that r-FFFS and r-BIS would mediate the relationship between mindfulness and psychological distress, and 2) that mindfulness would moderate the relationship between r-FFS and r-BIS and psychological distress. We did not generate specific hypotheses relating to the r-BAS sub-system as our focus was on psychological distress rather than the positive

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emotional states associated with reward sensitivity, although we did include r-BAS in mediation and moderation analyses for exploratory purposes. Unlike previous studies to date that have used measures of Gray's original Reinforcement Sensitivity Theory (o-RST) we used the Jackson 5 to measure the three sub-systems of r-RST (Jackson, 2009). The use of the Jackson 5 measure allows a more refined investigation of the relationship between r-RST, mindfulness and psychological functioning that is consistent with the revised theory. 2. Methods 2.1. Participants and procedure A sample of 452 participants were recruited of which (72%) were female and the mean age was 21.4 years (ages ranged from 16 to 57 years). The majority (69%) of the participants were Caucasian, 20% were Asian (20%), and 11% ‘other’ ethnicity. Participants were either undergraduate students who received course credit for participating in the study (around 80% of the participants) or a community sample recruited through social media. For recruitment through social media, a link to an online survey was posted on relevant Facebook sites. All participants completed the battery of measures online using Qualtrics survey software. The study received ethical clearance from the school's ethical review process. 2.2. Measures 2.2.1. r-RST The Jackson 5 (Jackson, 2009) is a 30-item scale measuring r-BAS, r-BIS, r-Fight, r-Flight and r-Freeze, as described above. Higher scores reflect higher activity of the motivational systems. The internal consistency of the scales in this study were; r-BAS (α = .80), r-BIS (α = .70), r-Fight (α = .80), r-Flight (α = .67), r-Freezing (α = .67) and rFFFS (α = .71). Other studies have reported higher levels of alpha on r-Flight and r-Freezing (e.g. Jackson, 2009). As the total r-FFFS score has greater reliability, and has been typically used in previous research, a total score was used in the current study. 2.2.2. Mindfulness The Five Facet Mindfulness Questionnaire (FFMQ; Baer, Smith, Hopkins, Krietemeyer, & Toney, 2006) is a 39-item self-report measure that examines five components of mindfulness: observation of one's internal experience and sensations (FFMQ-observe); non-judging of experience (FFMQ non-judging); the ability to describe one's emotional experience (FFMQ-describe); non-reactivity to inner experience (FFMQ-non-reactivity); and acting with awareness (FFMQ-act-withawareness). The internal reliability of the scales in the present study were: FFMQ-observe (α = .81), FFMQ-describe (α = .87), FFMQ-actwith-awareness (α = .89), FFMQ-non-judging (α = .87), FFMQ-nonreactivity (α = .72) and FFMQ-total (α = .82). 2.2.3. Psychological distress The short form of the Depression, Anxiety and Stress Scale-short form (DASS; Lovibond & Lovibond, 1995) is a 21 item self-report measure that includes a depression scale measuring dysphoria, hopelessness, devaluation of life, self-deprecation, lack of interest/ involvement, anhedonia and inertia; an anxiety scale measuring autonomic arousal, skeletal muscle effects, situational anxiety and subjective experience of anxious affect; and a stress scale measuring difficulty relaxing, nervous arousal, and agitation, irritability, and impatience. Higher scores reflect higher levels of psychological distress. The internal reliability of the scales in the present study were: Depression (α = .88), Anxiety (α = .76), and Stress (α = .84).

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3. Results

Table 2 Summary of hierarchical regression analysis for variables predicting DASS-total scores controlling for gender.

3.1. Means, standard deviations and correlations between variables

Criterion: DASS total

The means, standard deviations and correlations between variables are presented in Table 1. As gender differences are often found on measures of depression, anxiety and stress a series of t-tests were carried out to assess whether gender differences were present on the scores reported in Table 1. Female participants scored higher than males on r-FFFS (54.1 and 50.9 respectively; t(447) = −3.90, p b .001) and the DASS-stress sub-scale of the DASS (13.91 and 11.67 respectively; t(447) = − 2.47, p = .014). Female participants scored lower than males on the FFMQ-non-reactivity sub-scale of the FFMQ (17.91 and 19.27 respectively; t(447) = 3.02, p = .003). No statistically significant differences were found on any of the other measures The r-RST variables were all significantly correlated in the expected direction with the DASS-total score (see Table 1). r-BAS showed a negative association with the DASS-depression sub-scale, while r-BIS showed a significant and positive association with the DASS-stress sub-scale. r-FFFS was significantly and positively correlated with all three sub-scales of the DASS. In line with previous findings, the FFMQobserve sub-scale showed a positive association with DASS-total scores, suggesting that, simply paying attention to one's inner experience is associated with higher levels of psychological distress. The remaining four FFMQ sub-scales showed an expected negative relationship with the DASS-total score. 3.2. Mindfulness as a predictor of psychological distress To assess whether mindfulness would predict psychological distress over and above the three r-RST personality variables, a hierarchical linear regression analysis was performed with the DASS-total score as the criterion. Gender was entered into step 1 due to the differences in mean scores between males and females on the r-FFFS, DASS-stress and FFMQ-non-reactivity measures. The three r-RST variables were entered into step 2 and the five FFMQ sub-scales entered in step 3. Gender did not contribute significantly to the regression model in step 1, and accounted for less than 1% of the variation in DASS-total scores. In step 2 the overall model explained 10.1% of the variance (R = .32, R2 = .10, ΔF(3,443) = 16.15, p b .001). Of the three r-RST variables, only r-FFFS significantly predicted the DASS-total score (see Table 2). An additional 29.7% (ΔR2 = .30) of the variance in DASStotal scores was explained by adding the five FFMQ sub-scale scores into to the regression model in step 3, with the overall model in step 3 explaining 39.8% of the variance (R = .63, R2 = .40, ΔF(5,438) = 43.3, p b .001). When all predictors were included in stage three of the regression model, r-FFFS remained a significant predictor, while all FFMQ sub-

UnStd. B

SE B

Step 1 Model summary Gender

2.17

2.17

.05

Step 2 Model summary Gender r-BAS r-BIS r-FFFS

−.35 −.38 −.05 .80

2.10 .27 .30 .13

−.01 −.07 −.01 .31

−.17 −1.43 −.17 6.11⁎⁎⁎

−.45 −.08 −.32 .29 .44 −.19 −.99 −1.24 −1.07

1.76 .23 .25 .12 .16 .14 .15 .15 .21

−.01 −.01 −.05 .11 .13 −.06 −.29 −.37 −.23

−.26 −.35 −1.28 2.54⁎ 2.69⁎⁎ −1.40 −6.69⁎⁎⁎ −8.43⁎⁎⁎ −5.12⁎⁎⁎

Step 3 Model summary Gender r-BAS r-BIS r-FFFS FFMQ-observe FFMQ-describe FFMQ-act-with-awareness FFMQ-non-judge FFMQ-non-react

Std. B

t

R

R2

ΔR2

.05

.002

.32

.10

.10⁎⁎⁎

.63

.40

.30⁎⁎⁎

1.00

r-BAS = Jackson 5 Behavioral Activation System; r-BIS = Jackson 5 Behavioral Inhibition System; r-FFFS = Flight, Fight, Freeze System; FFMQ = Five Facets Mindfulness Questionnaire; DASS = Depression, Anxiety and Stress Scale. ⁎ p b .05. ⁎⁎ p b .01. ⁎⁎⁎ p b .001.

scales with the exception of the FFMQ-describe sub-scale significantly predicted DASS-total scores (see Table 2). 3.3. r-FFFS and r-BIS as mediators of the relationship between mindfulness and psychological distress The hypothesis that r-FFFS and r-BIS would mediate the relationship between mindfulness and psychological distress was tested using the PROCESS procedure (Model 4; Hayes, 2013). Model 4 of this procedure allows multiple mediators to be assessed in a single model. The total DASS score was entered as the criterion and the total FFMQ score as the predictor. As the FFMQ-observe sub-scale showed a positive association with psychological distress in the current study while the remaining FFMQ sub-scales all showed a negative association, and as this anomaly has been reported in other studies (e.g., Reese et al., 2015) the total FFMQ score was recalculated excluding the FFMQ-observe sub-scale. The Analyses were carried out with and without the Observe

Table 1 Means, standard deviations and correlations of personality, mindfulness and psychological distress variables.

1 2 3 4 5 6 7 8 9 10 11 12 13

r-BAS r-BIS r-FFFS FFMQ-observe FFMQ-describe FFMQ-act-with-awareness FFMQ-non-judgment FFMQ-non-reactivity FFMQ-total DASS-stress DASS-anxiety DASS-depression DASS-total

M

SD

2

3

4

5

6

7

8

9

10

11

12

13

21.97 22.12 53.23 23.41 25.29 27.19 26.94 18.30 121.12 13.27 7.27 7.70 28.23

3.53 3.35 7.95 5.90 6.25 6.02 6.20 4.37 14.76 8.69 8.28 6.81 20.69

.04 – – – – – – – – – – – –

−.12⁎ .38⁎⁎

.25⁎⁎ .08 −.02 – – – – – – – – – –

.19⁎⁎ −.03 −.23⁎⁎ .30⁎⁎

.05 −.17⁎⁎ −.33⁎⁎ −.19⁎⁎ .13⁎⁎

.13⁎⁎ −.14⁎⁎ −.22⁎⁎ −.32⁎⁎

.14⁎⁎ −.01 −.13⁎⁎ .48⁎⁎ .27⁎⁎ −.13⁎⁎ −.23⁎⁎

.29⁎⁎ −.11⁎ −.37⁎⁎ .46⁎⁎ .70⁎⁎ .53⁎⁎ .42⁎⁎ .45⁎⁎

−.06 .14⁎⁎ .29⁎⁎ .12⁎⁎ −.13⁎⁎ −.43⁎⁎ −.42⁎⁎ −.17⁎⁎ −.40⁎⁎

−.06 .06 .28⁎⁎ .11⁎ −.15⁎⁎ −.38⁎⁎ −.39⁎⁎

−.14⁎⁎ .08 .24⁎⁎ .21⁎⁎ −.15⁎⁎ −.42⁎⁎ −.49⁎⁎

−.10⁎ .11⁎ .31⁎⁎ .16⁎⁎ −.17⁎⁎ −.47⁎⁎ −.50⁎⁎

.03 −.29⁎⁎ .64⁎⁎

−.03 −.41⁎⁎ .66⁎⁎ .58⁎⁎

−.07 −.43⁎⁎ .90⁎⁎ .83⁎⁎ .87⁎⁎

– – – – – – – – – – –

– – – – – – – – –

– – – – – – – –

.05 .42⁎⁎ – – – – – – –

– – – – – –

– – – – –

– – – –

– – –

– –

–

Note: r-BAS = Jackson 5 Behavioral Activation System; r-BIS = Jackson 5 Behavioral Inhibition System; r-FFFFS = Flight, Fight, Freeze System; FFMQ = Five Facets Mindfulness Questionnaire; DASS = depression, Anxiety and Stress Scale. ⁎ p b .05. ⁎⁎ p b .01.

P.H. Harnett et al. / Personality and Individual Differences 99 (2016) 100–105

sub-scale included in the total FFMQ score. The general pattern of results was unaffected by the measure used, although the proportion of variance explained in the mediation and moderation models reported below was less when the Observe sub-scale was included in the total FFMQ score. For ease of interpretation only the modified FFMQ-total (observe sub-scale excluded) is reported. The three measures of r-RST were entered as the mediator variables (r-BAS for exploratory purposes). Gender was entered as a covariate. The overall mediation model accounted for 32% of the variability in DASS-total scores (R = .56, R2 = .32, F(5442) = 41.02, p b .001). The covariate, Gender, was not associated with DASS-total. The FFMQ-total score has a direct effect on DASS-total (−.82, see Table 3). Of the three r-RST sub-system measures, r-FFFS was found to have a significant indirect effect (−.07) on DASS-total, indicating that sensitivity to threat significantly mediated the relationship between mindfulness and psychological distress. 3.4. Mindfulness as a moderator of the relationship between the RST subsystems and psychological distress The hypothesis that mindfulness would moderate the relationship between the RST sub-systems and psychological distress was tested using (Hayes, 2013) PROCESS procedure (Model 1). A series of analyses were carried out with the DASS-total score as the criterion, the three rRST measures entered separately as predictors, the modified FFMQ-total score as the moderator and Gender as a covariate. To minimize the likelihood of Type I error the DASS-total score was used in the first series of analyses rather than the individual sub-scales. However, follow-up analyses were carried out separately with each of the three DASS subscale scores as the criterion when mindfulness was found to moderate the relationship between personality and the total DASS score to assess whether the moderation effect applied to depression, anxiety or stress. The first analysis using r-BAS as the predictor, DASS-total as the outcome, FFMQ-total as the moderator and entering Gender as a covariate found that the overall model explained 31.1% of the variance in DASStotal (R = .56, R2 = .31, F(4444) = 50.18, p b .001). Gender showed no significant relationship with DASS-total in the model. The FFMQtotal score was a significant predictor of DASS-total (b = −.89, p b .001; see Table 4). However, r-BAS did not significantly predict DASS-total and there was no significant moderating effect of FFMQ. The second analysis used r-BIS as the predictor of DASS-total, FFMQtotal as the moderator and Gender entered as a covariate. The overall model explained 30.8% of the variance in total DASS (R = .56, R2 = .31, F(4444) = 49.54, p b .001). Gender showed no significant relationship with DASS-total in the model. The FFMQ-total score was a significant predictor of DASS-total (b = −.87, p b .001). r-BIS did not significantly predict DASS-total and there was no significant moderating effect of FFMQ. The final analysis used r-FFFS as the predictor of DASS-total, FFMQ-total as the moderator and Gender as a covariate. The overall model explained 32.3% of the variance in DASS-total (R =

Table 3 Direct and indirect effects of FFMQ on DASS through r-RST sub-systems controlling for gender. DV = DASS-total

FFMQ

Total effect Direct effect Total indirect effect r-BAS r-BIS r-FFFS

Effect

−.87a −.82a −.05 .01 .01 −.07a

SEboot

.06 .07 .03 .02 .01 .03

BC 95% CI

103

Table 4 Summary of moderated regression analyses testing the moderating effect of mindfulness on the relationship between personality and psychological distress controlling for gender. DVI: DASS-total

β

MSE

t

IV: r-BAS Model summary r-BAS FFMQ total r-BAS x FFMQ total Gender

.15 −.89 .02 .72

.24 .06 1.81

.65 −13.87⁎⁎⁎ −1.43 .40

IV: r-BIS Model summary r-BIS FFMQ total r-BIS × FFMQ total Gender

.10 −.87 −.003 .81

.25 .06 .02 1.81

.41 −13.76⁎⁎⁎ −.18 .45

IV: r-FFFS Model summary r-FFFS FFMQ total r-BAS × FFMQ total Gender

.25 −.80 −.02 .20

.11 .07 .01 1.82

2.23⁎ −11.86⁎⁎⁎ −2.17⁎ .11

R

R2

.56

.31

ΔR2

50.18⁎⁎⁎

.003

.56

1.76

49.54⁎⁎⁎

.31

b.001

.57

F

.03

52.90⁎⁎⁎

.32

.01

4.69⁎

r-BAS = Jackson 5 Behavioral Activation System; r-BIS = Jackson 5 Behavioral Inhibition System; r-FFFS = Flight, Fight, Freeze System; FFMQ = Five Facets Mindfulness Questionnaire; DASS = depression, Anxiety and Stress Scale. ⁎ p b .05. ⁎⁎ p b .01. ⁎⁎⁎ p b .001.

.57, R2 = .32, F(4443) = 52.90, p b .001). Both the FFMQ-total score (b = −.80, p b .001) and r-FFFS scores (b = 0.25, p = .03) were found to significantly predict DASS-total scores. The R2 increase due to the interaction between FFMQ-total and r-FFFS was significant (R2change = .007, F(1, 443) = 4.69, p = .03) supporting the hypothesis that mindfulness would moderate the relationship between threat sensitivity and psychological distress. Simple slope analysis found that r-FFFS was associated with increased psychological distress when mindfulness was low (−1 SD, b = .45, t = 3.13, p = .002) or moderate (b = .25, t = 2.32, p = .03), but had no significant effect when mindfulness was high (+ 1 SD, b = .06, t = .42, p = .67). Three follow-up analyses were carried out using each of the DASS sub-scales as the criterion variable. These analyses found that mindfulness moderated the relationship between the r-FFFS sub-system and the anxiety subscale of the DASS, with r-FFFS and FFMQ-total explaining 20.0% of the variance in DASS-anxiety (R = .49, R2 = .20, F(3445) = 37.1, p b .001). r-FFFS (b = 1.10, t(445) = 2.75, p = .006) and FFMQ (b = −.19, t(445) = −7.73, p b .001) were both found to independently predict DASS-anxiety. The R2 increase due to the interaction was significant (R2change = .011 F(1, 445) = 5.86, p = .016) indicating that mindfulness moderated the relationship between r-FFFS and DASS-anxiety. Simple slope analysis found that r-FFFS was associated with increased anxiety when mindfulness was low (− 1 SD, b = .19, t = 3.69, p b .001) or moderate (b = .11, t = 2.75, p = .006), but had no significant effect when mindfulness was high b = .03, t = 0.64, p = .52). There were no significant moderating effects evident for the DASS-depression or the DASS-stress sub-scales. 4. Discussion

Lower

Upper

−.99 −.95 −.12 −.02 −.02 −.13

−.75 −.68 .01 .04 .04 −.01

Note: BC = Bias Corrected; CI = Confidence Interval; FFMQ = Five Facets Mindfulness Questionnaire; r-BAS = Jackson 5 Behavioral Activation System; r-BIS = Jackson 5 Behavioral Inhibition System; r-FFFFS = Flight, Fight, Freeze System. a Confidence intervals not including zero.

The present study examined relationships between personality, mindfulness and psychological distress in a non-clinical sample. In general, measures of personality and mindfulness displayed the expected associations with psychological distress. Low r-BAS was associated with higher levels of self-reported depression, while higher r-FFFS was associated with higher levels of depression, stress and anxiety. Contrary to expectations, higher r-BIS was associated with higher scores on the stress sub-scale of the DASS, but not the anxiety sub-scale. This unexpected finding might be explained by the conceptualization of ‘anxiety’

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and ‘stress’ used in the DASS. The DASS-stress sub-scale includes items that, from an r-RST perspective might be thought of as anxiety, such as ‘finding it hard to relax’ and ‘agitation’, while the DASS-anxiety subscale includes items such as ‘feeling close to panic’ which would be more related to the r-FFFS. While the focus of the present study was on ‘psychological distress’, a more refined examination of the relationship between r-RST and psychological functioning should include measures that better differentiate symptoms of anxiety from fear and panic. Further, it is important to note that the r-BIS sub-scale of the Jackson 5 has recently been criticized for an apparent lack of convergent and discriminant validity (Corr, 2016) and a recommendation that alternative measures be used when testing hypotheses involving the r-BIS construct. In the present study r-BAS was negatively associated and the r-BIS and r-FFFS were both positively associated with the total DASS score, as would be expected. In general, mindfulness showed expected associations with psychological distress. The FFMQ-describe, act with awareness and non-judge sub-scales were all negatively associated with the depression, anxiety and stress sub-scales of the DASS and the total DASS score. The DASSnon-react sub-scale was negatively associated with the DASS-stress sub-scale, but not the depression or anxiety sub-scales. We found that the FFMQ-observe sub-scale was positively associated with all subscales of the DASS. This finding is consistent with Hamill et al. (2015) who found the FFMQ-observe sub-scale to be positively associated with the DASS anxiety and stress sub-scales. These authors suggest that the FFMQ-observe sub-scale focuses on attention to internal sensations and external stimuli that may represent hypervigilant behaviors, particularly in individuals who have not engaged in a regular mindfulness practice. Desrosiers, Vine, Curtiss, and Klemanski (2014) found that the relationship between observing and symptoms of anxiety and depression depends on an individual's capacity to observe nonreactively, as this may assist individuals to avoid engaging automatically in maladaptive coping strategies (e.g. rumination or worry) and instead, enabling them to employ more adaptive strategies. We found that mindfulness significantly improved the prediction of psychological distress over and above the measures of r-RST. Indeed, a hierarchical regression showed that including the five mindfulness sub-scales in the regression explained 40% of the variance in psychological distress compared to 10% when the personality measures were entered alone. The meditational analysis provided partial support to our hypothesis in finding that r-FFFS mediated the relationship between mindfulness and psychological distress. This finding suggests that threat sensitivity rather than reward sensitivity (r-BAS) or the conflict resolution (r-BIS) aspects of RST are important in the relationship between mindfulness and psychological distress. Given that high sensitivity of the r-FFFS is associated with negative affect and avoidance behaviors, it is possible that our result reflects a greater capacity to regulate negative emotional states in people with higher levels of trait mindfulness. This seems more plausible than the suggestion that trait mindfulness directly lowers the sensitivity of the r-FFFS at the neurological level. We should note however that higher levels of trait mindfulness has been found to be associated with higher levels of vagal tone (Krygier et al., 2013), which in turn has been found to dampen the activity of the neurological structures underlying the r-RST systems (Porges, 2011; Thayer & Lane, 2000). Further research is required to understand the mechanisms to explain the mediation effect found in this study. The present study did not find evidence to support mindfulness as a moderator of the relationship between either r-BAS or r-BIS and psychological distress. However, we did find that mindfulness moderated the relationship between the r-FFFS and the anxiety sub-scale of the DASS. For individuals who reported low levels of mindfulness, higher threat sensitivity was associated with higher levels of anxiety. This association was much weaker for individuals who reported higher levels of mindfulness, with little increase in anxiety observed as threat sensitivity increased, suggesting that mindfulness buffered the impact of threat sensitivity, a result consistent with the moderation hypothesis.

4.1. Implications and future directions Our results support the view that a high level of trait mindfulness can facilitate the regulation of emotions, even for individuals temperamentally predisposed with a high sensitivity to threat. Our results also show that low to moderate levels of mindfulness increase the vulnerability of threat sensitivity to psychological distress compared to people with high mindfulness. A testable implication of these results is that mindfulness-based therapies may be primarily effective for threatsensitive individuals with low trait mindfulness, but less effective for individuals with low threat-sensitivity or high pre-existing levels of trait mindfulness. Future research aimed at differentiating between people who respond or fail to respond to mindfulness-based therapies would be useful to ensure that mindfulness-based interventions target individuals most likely to benefit (Keng et al., 2011). The present study suggests that individual differences in measures of the r-RST sub-systems would be a profitable target of investigation for future research. 4.2. Limitations The results of this study should be interpreted in the light of a number of limitations. First, the study was cross-sectional and therefore unable to establish causal relationships between variables. Second, the study used a non-clinical community sample of mainly young people of European descent, limiting the generalization of the results. Third, the Jackson 5 was used to measure the r-RST constructs. At the time the study was carried out, this was the only available measure specifically developed to measure r-RST. In the light of recent concerns regarding the convergent and discriminant validity of the measure, particularly the r-BIS sub-scale, future studies should consider using other measures of r-RST such as the revised Reinforcement Sensitivity Theory Questionnaire (Reuter, Cooper, Smillie, Markett, & Montag, 2015) or the Reinforcement Sensitivity Theory of Personality Questionnaire (Corr & Cooper, 2016; see Corr, 2016). 5. Conclusion The present study replicates and extends previous research showing that r-FFFS mediated the relationship between mindfulness and psychological distress, while mindfulness moderated the relationship between r-FFFS and psychological distress. Both results are consistent with the interpretation that high trait mindfulness can mitigate the negative impact of high sensitivity to threat. However, the present study cannot shed light on the mechanisms involved—the possibility that trait mindfulness directly decreases the sensitivity of the r-FFFS system at the neurological level as opposed to reflecting a greater capacity of individuals with high trait mindfulness to regulate negative affect (the output of r-FFFS). To date, studies that have found similar results (e.g., Hamill et al., 2015) have used measures of threat sensitivity derived from Gary's original RST. When examined from the perspective of the revised RST (in which BIS is separated from FFFS), the present study did not find mindfulness to moderate the relationship between BIS and psychological distress. Thus, while the overall pattern of results is consistent with past research, it maybe that r-RST will provide a more refined understanding of the relationship between personality, mindfulness and psychological distress. The present research suggests that acquiring the skills from learning and practicing mindfulness therapy techniques is potentially useful for threat-sensitive individuals with low to moderate levels of mindfulness. Individuals naturally reporting high levels of mindfulness and who are experiencing psychological distress may need to learn to employ alternative emotion regulation strategies (although those higher in mindfulness showed the lowest levels of distress). Further research using longitudinal designs is needed to determine whether the beneficial

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