خجالت زدگی فیزیولوژیکی در افراد مبتلا به اختلال اضطراب اجتماعی با و بدون شکایت خجالت زدگی : دو زیر گروه؟

Abstract This study investigates whether social anxiety disorder (SAD) patients with blushing complaints show heightened physiological blushing and arousability in social situations than SAD patients without blushing complaints and healthy controls. SAD blushers (n = 32), SAD non-blushers (n = 34), and healthy controls (n = 25) conducted two social tasks. The physiological responses cheek and forehead blood flow, cheek temperature, and skin conductance were recorded, as well as confederates-observed blushing. The SAD blushers showed more physiological blushing (cheek temperature and blood flow) than SAD non-blushers and observers detected this difference. This finding was also present in comparison to the controls, except for blood flow. For blood flow SAD blushers and controls did not differ but SAD non-blushers showed a ‘suppressed response’: a smaller cheek blood flow increase during the interaction and no recovery compared to the other groups. Furthermore, on skin conductance no differences between groups were observed. Discussed is to what extent SAD blushers and SAD non-blushers represent two qualitative distinct subgroups of SAD.

Results 2.1. Validity of the classification of SAD with and without blushing complaints To check whether the classification of the SAD blushers versus SAD non-blushers was reliable, various blush indices were used (see Table 1 for mean and standard deviations). In line with expectations, the SAD blushers scored higher than the SAD non-blushers on the blush item of the SPAI (item 32 ‘I experience the following during a social situation: blushing’), t(48) = 4.7, p = .000, d = 1.3). For treatment purposes patients formulated five idiosyncratic fearful social situations. These situations included more blush situations for the SAD blushers than for the SAD non-blushers, t(63) = 5.1, p = .000, d = 1.2). During the social tasks the SAD blushers rated themselves as blushing more than the SAD non-blushers, t(64) = 4.4, p = .000, d = 1.1. Not only did the SAD blushers rate themselves as blushing more than the SAD non-blushers, also the confederates identified that the SAD blushers blushed more than the SAD non-blushers, t(64) = 4.6, p = .000, d = 1.1. These results support the validity of the classification of the blushers versus the non-blushers within the SAD group. It is worth noting that the observers also detected the SAD blushers to blush more than the normal controls, t(54) = 3.8, p = .000, d = 1.0, but did not see differences between the SAD non-blushers and the normal controls. 2.2. Correlations between the physiological measures See Table 2 for the correlations. For responsiveness (social task minus baseline) the three blushing indices (cheek and forehead blood flow and cheek temperature) correlated significantly. In contrast, skin conductance level did not correlate with the blushing measures. For recovery (social task minus recovery) only cheek and forehead blood flow correlated and no correlation between temperature and blood flow emerged. Again, skin conductance level did not correlate with the blushing measures. Table 2. Correlations between the four physiological indices for responsiveness and recovery. Physiological indices Cheek blood flow Forehead blood flow Cheek temperature Responsiveness to the social taska Forehead blood flow .25* Cheek temperature .30* .31* Skin conductance .08 −.12 −.01 Recovery from the social taskb Forehead blood flow .24* Cheek temperature .05 .11 Skin conductance .09 −.04 −.12 a Calculated by subtracting baseline assessments from social task assessments. b Calculated by subtracting recovery assessments from social task assessments. * Correlation is significant at the 0.05 level (two-tailed). Table options 2.3. Correlations of the physiological measures with self- and observer-ratings See Table 3 for correlations. In contrast to previous studies (see the overview of Drummond et al., 2007) we found cheek blood flow to correlate with self- and observer-rated blush in our normal control sample. No such relations were found in both the SAD groups. Self- and observer-rated blush did not correlate with forehead blood flow, cheek temperature and skin conductance level in any of the three groups. Table 3. Correlations between the four physiological measuresa and self- and observer-rated blush for each of the three groups. Physiological indices Normal controls SAD blushers SAD non-blushers Self-report blush Observers-rated blush Self-report blush Observers-rated blush Self-report blush Observers-rated blush Cheek blood flow .53* .26 .34+ .16 .12 −.01 Forehead blood flow −.01 .05 −.01 −.02 −.11 −.06 Cheek temperature .38+ .11 .19 .26 .03 .15 Skin conductance −.02 −.10 −.02 .12 −.04 .05 a Calculated by subtracting baseline assessments from social task assessments. * Correlation is significant at the 0.05 level (two-tailed). + Correlation is borderline significant (p < .10, two-tailed). Table options 2.4. Main analyses Drummond (2001) argues that both cheek and forehead blood flow reflect the same blushing responses and our data indeed showed cheek and forehead blood flow to correlate significantly (see above and Table 3). Moreover, the effects from the ANOVA analyses of both blood flow measures were highly identical.1 Therefore, to increase the reliability and, therefore, the power of our analyses we decided to construct one blood flow variable by averaging the forehead and cheek blood flow assessments for each of the three assessments times (baseline, social task and recovery). First, the repeated measures ANOVAs were run with the SAD groups combined versus normal controls as between group variable and with phase (baseline, social task, recovery) as within group variable. Second, the same analyses were run with the three different groups (SAD blushers, SAD non-blushers, normal controls) as between group variable. See Table 4 for the mean levels for the four physiological assessments in each phase of the experiment for the three different groups. See Fig. 1 for graphs of the three physiological indices, cheek temperature, combined blood flow of cheek and forehead, and skin conductance in each phase of the experiment for the different groups. Table 4. Means and standard deviations of the four physiological indices of baseline, social task and recovery for the SAD blushers, SAS non-blushers and normal control group. Cheek blood flow Forehead blood flow Cheek temperature Skin conductance levela SAD blushers n = 31 (S.D.) SAD non-blushers n = 28 (S.D.) Normal controls n = 23 (S.D.) SAD blushers n = 31 (S.D.) SAD non-blushers n = 28 (S.D.) Normal controls n = 23 (S.D.) SAD blushers n = 31 (S.D.) SAD non-blushers n = 29 (S.D.) Normal controls n = 23 (S.D.) SAD blushers n = 31 (S.D.) SAD non-blushers n = 28 (S.D.) Normal controls n = 22 (S.D.) Baseline 4.47 (3.98) 5.19 (4.14) 2.84 (2.01) 4.00 (4.44) 4.17 (3.65) 4.68 (3.74) 34.1 (1.4) 33.5 (1.1) 33.6 (1.0) 2.58 (0.54) 2.53 (0.77) 2.42 (0.68) Social task 6.39 (5.04) 5.84 (4.57) 4.67 (4.07) 5.70 (5.31) 5.20 (4.34) 6.63 (3.61) 34.4 (1.3) 33.6 (1.1) 33.8 (1.1) 2.65 (0.50) 2.60 (0.74) 2.60 (0.67) Recovery 5.51 (5.15) 6.06 (4.64) 4.12 (3.71) 4.27 (5.57) 5.34 (4.80) 5.15 (4.28) 34.6 (1.2) 33.8 (1.1) 34.0 (1.1) 2.51 (0.51) 2.52 (0.75) 2.45 (0.65) a Square root transformation. Table options Depicted are the three physiological indices, cheek temperature, blood flow, and ... Fig. 1. Depicted are the three physiological indices, cheek temperature, blood flow, and skin conductance, during baseline, social task and recovery for the SAD blushers, SAD non-blushers and normal control group. Figure options 2.4.1. Phase effect Comparing the combined SAD group versus the normal controls, a quadratic phase effect was found for each of the three physiological measures (blood flow: F(1,80) = 45.1, p = .000, ξ2 = .36; cheek temperature: F(1,81) = 6.1, p = .016, ξ2 = .07; skin conductance level: F(1,79) = 98.3, p = .000, ξ2 = .55). The exact same pattern was found in the analyses in which the three different groups were included in the analyses. 2 Post hoc paired t-tests revealed that, as expected, participants’ physiological level increased for all measures from baseline to task (blood flow: t(81) = 7.7, p = .000, d = 1.7; cheek temperature: t(82) = 7.7, p = .000, d = 1.7; skin conductance: t(80) = 6.3, p = .000, d = 1.4) and decreased from task to recovery (blood flow: t(81) = 4.0, p = .000, d = 0.9; cheek temperature: t(82) = 7.3, p = .000, d = 1.6; skin conductance: t(80) = 10.6, p = .000, d = 2.4). In addition, the physiological indices, except for skin conductance, showed a linear phase effect (see the footnote 2) (blood flow: F(1,80) = 21.0, p = .000, ξ2 = .21; cheek temperature: F(1,81) = 62.8, p = .000, ξ2 = .43). That is, the physiological levels increased over time, with higher physiological levels during recovery than during baseline (blood flow: t(81) = 5.1, p = .000, d = 1.3; cheek temperature: t(82) = 8.6, p = .000, d = 1.9). 2.4.2. Group effect No main effects for group were found for the three physiological indices comparing the combined SAD groups with the normal controls. However, when the three different groups were included in the analyses cheek temperature3 did show a main effect for group, F(2,80) = 3.2, p = .047, ξ2 = .07. That is, SAD blushers had an overall higher cheek temperature than the SAD non-blushers, F(1,58) = 5.5, p = .022, ξ2 = .09. The overall cheek temperature of the normal control group was in between the two SAD groups. The difference between the normal control group and the SAD blushers was borderline significant, F(1,52) = 2.8, p = .099, ξ2 = .05, and no difference was found with the SAD non-blushers, F(1,50) = 0.4, ns. 2.4.3. Interaction effect With regard to cheek temperature no interaction effects between phase and group were found; neither for the analyses in which the combined SAD group was compared to the normal controls as for the analyses in which the three groups were included as between subject variable. As for blood flow, no interaction effects appeared in the analyses with the combined SAD group versus the normal controls, however, with the three groups as between subject variables, no linear but a significant quadratic interaction effect emerged, F(2,79) = 6.4, p = .003, ξ2 = .14. To unravel the quadratic interaction, the repeated measures ANOVA was ran again with only the two SAD groups as between variable (SAD blushers versus SAD non-blushers). This analysis showed a quadratic interaction effect, F(1,57) = 12.8, p = .001, ξ2 = .18, which indicated that the SAD blushers compared to the SAD non-blushers showed a greater increase from baseline to social task, t(57) = 2.4, p = .02, d = .64, and a greater decrease from social task to recovery, t(57) = 3.8, p = .005, d = 1.0. Then, each of the two SAD groups was compared separately to the normal control group. Against expectations, no interaction effects were found between the SAD blushers and the normal control group. Surprisingly, between the SAD non-blushers and the controls the quadratic interaction was significant F(1,49) = 7.6, p = .008, ξ2 = .14. This interaction indicated that the normal controls were more responsive from baseline to social task, t(49) = 2.2, p = .03, d = .63, as well as from social task to recovery, t(49) = 2.8, p = .008, d = .80, than the SAD non-blushers. In other words, the SAD non-blushers showed a flatter blush response pattern than both the SAD blushers and the normal control group. With regard to skin conductance level4, the analysis with the combined SAD group versus normal controls showed both a quadratic, F(1,79) = 8.2, p = .005, ξ2 = .09, and a linear interaction, F(1,79) = 5.2, p = .026, ξ2 = .06. The linear interaction resulted from a general greater decrease for the SAD group than for the normal controls. The quadratic interaction was explained by the normal controls to have a greater increase of skin conductance level from baseline to social task than the SAD group, t(79) = 3.5, p = .001, d = 0.8. No significant difference appeared for social task to recovery. The analyses in which the three groups were included as between subjects variables specified that the linear interaction was explained mainly by a greater decrease in skin conductance level for the SAD blushers compared to the normal control subjects, F(1,51) = 7.4, p = .009, ξ2 = .13. Moreover, the quadratic interaction was mainly explained by a greater responsiveness to the social tasks of the normal controls compared to the SAD non-blushers, F(1,48) = 11.3, p = .002, ξ2 = .19. That is, the increase from baseline to social task, F(1,50) = 10.4, p = .002, ξ2 = .18, and the decrease from social task to recovery was greater for the normal controls than for the SAD non-blushers, F(1,48) = 7.8, p = .008, ξ2 = .14. The general picture that seemed to appear is that the normal controls exhibited a greater responsiveness to the social tasks than the SAD patients. It is worth noting that the two SAD groups showed a somewhat higher, but non-significant, baseline level of skin conductance than the normal control group (combined SAD group: 2.6, S.D. = .7; normal controls: 2.4, S.D. = .7). This might explain the greater responsiveness of the normal control group compared to the SAD group.