واکنش پذیری به محرک های وابسته‌ به‌ انگیزش‌ و تحریک‌ درونی در هراس شبانه

Abstract In this study, patients with panic disorder (PD) who suffered nocturnal panic (NP) attacks were compared with PD patients who never experienced NP attacks and healthy controls. Three tasks were chosen to evaluate attention to cardiac cues, reactivity to induction of respiratory cues, and reactivity to relaxation cues. Relative to healthy controls, PD groups reported more fear of all three tasks and showed more physiological arousal in response to the hyperventilation task. The only task on which the two PD groups differed was the relaxation task, where nocturnal panickers were significantly more distressed. These findings are consistent with the notion that nocturnal panickers are fearful of states involving a diminution of conscious awareness or vigilance.

3. Results 3.1. Baseline self-report There was a significant main effect of Group for the ACQ [F(2,99)=6.6, p<0.01], the BSQ [F(2,99)=17.0, p<0.01] and the STAI-S [F(2,99)=15.2, p<0.01]. Post hoc testing showed that both panic groups had higher scores on these measures than did the control group but that there were no differences between the two panic groups. Means and standard deviations are presented in Table 1. Table 1. Means (standard deviations) of self report measures NP DP Control ACQa 1.9 (0.6) 2.0 (0.8) 1.2 (0.5) BSQa 2.5 (0.8) 2.7 (0.8) 1.3 (0.5) STAIa 47.2 (10.2) 47.3 (10.8) 30.4 (11.4) Cardiac tracking Anticipatory anxiety (0–8) 2.6 (1.4) 2.5 (1.5) 0.5 (0.7) Average anxiety (0–8)a 2.2 (1.5) 1.9 (1.2) 0.8 (0.8) Maximum anxiety (0–8)a 2.9 (1.8) 2.4 (1.7) 1.1 (1.0) Symptoms endorseda 3.2 (3.3) 2.9 (2.9) 0.4 (0.5) Average symptom intensityb 0.6 (0.7) 0.4 (0.6) 0.05 (0.09) Meditative relaxation Anticipatory anxiety (0–8) 2.1 (1.8) 1.4 (1.4) 0.5 (1.1) Average anxiety (0–8)c 2.4 (1.9) 1.6 (1.7) 0.5 (0.7) Maximum anxiety (0–8)c 3.4 (2.2) 2.2 (2.0) 0.6 (0.7) Symptoms endorseda 4.8 (4.3) 3.3 (3.5) 0.7 (0.2) Average symptom intensityb 1.0 (1.2) 0.6 (0.8) 0.05 (0.08) RRAQ averagec 3.2 (0.9) 2.6 (1.0) 1.5 (0.4) Hyperventilation Anticipatory anxiety (0–8) 3.0 (2.2) 3.2 (2.0) 0.8 (1.1) Average anxiety (0–8)a 3.5 (2.0) 3.8 (2.0) 1.4 (1.4) Maximum anxiety (0−8) a 4.3 (2.2) 4.6 (2.5) 1.6 (1.5) Symptoms endorsea 6.8 (3.9) 7.4 (4.6) 1.9 (2.4) Average symptom intensityb 1.6 (1.4) 1.9 (1.5) 0.2 (0.3) a Panic groups>control; p<0.01. b NP>control; p<0.05. c NP>DP>control; p<0.01. Table options 3.2. Cardiac tracking Self-report: We analyzed participants’ ratings of average and maximum anxiety using anticipatory anxiety as a covariate. There were significant between-group differences in both maximum anxiety [F(3,96)=27.4, p<0.001] and average anxiety [F(3,96)=34.1, p<0.001]. Groups also differed in both the total number of panic symptoms endorsed [F(2,98)=6.0, p<0.01] and the average intensity of these symptoms [F(2,97)=4.0, p<0.05]. Post hoc testing revealed that the two patient groups reported more anxiety and symptoms than the control group but did not differ from each other. The NP group reported higher symptom intensity than the control group, but the DP group did not differ from the others. (Refer to Table 1). Nine (19%) NPs, 4 (10%) DPs, and no control participants reported panic attacks during this task, but this difference did not reach statistical significance; nor were there group differences in the estimate of usual HR. There were six intervals during which participants were to count their HR. We compared these counts with the actual number of beats using a “degree of inaccuracy” measure [(actual-estimate/actual)×100] (from Ehlers & Breuer, 1992). The data clearly deviated from normal, and therefore we categorized the entire sample into overestimators (−10% or less), good estimators (within 10%) and underestimators (+10% or more). There were no significant differences among NPs, DPs and controls in these categories. Overall, participants tended to underestimate by 10–26%. This is similar to the error rate of 22–23% reported by Ehlers and Breuer (1992). The groups did not differ on the estimate of usual number of times their heart beats in 1 min. Furthermore, estimated usual HR correlated only weakly with degree of inaccuracy of heart beat estimation (r=−0.05 and −0.16); nor did the groups differ in terms of time estimation, although time estimation correlated moderately with degree of inaccuracy of HR in the cardiac tracking task (r=0.40). Overall, it appeared that estimates of usual number of heart beats and time did not confound the group comparisons. Physiology: Data from the two sets of trials were analyzed separately. A difference among groups emerged on only one physiological measure, EMG. During set 1, there was a trend toward a group×time interaction [F(5.4,250.1)=2.7, p<0.05], indicating different EMG response patterns, but the groups did not significantly differ at any given trial. No other differences were detected for this task. 3.3. Hyperventilation Self-report: Group differences were found for maximum [F(3,100)=62.3, p<0.001] and average anxiety [F(3,100)=56.0, p<0.001] when tested with anticipatory anxiety as a covariate. There were also group differences in symptoms reported [F(2,96)=11.4, p<0.01] and symptom intensity [F(2,100)=8.8, p<0.001]. As with the cardiac tracking task, panic patients consistently reported more anxiety and more symptoms than controls, but the two groups of panic patients did not differ from each other (see Table 1). Eighteen (38%) NPs, 16 (42%) DPs and no controls reported panic attacks. This was a significant overall difference (phi=0.31, p<0.01), but the panic groups do not differ from each other. Physiology: There were three phases of data collected during this task: baseline (30 s), hyperventilation (90 s) and recovery (300 s). Each phase was analyzed separately. There were no baseline differences for EMG, SCL or CO2. There were baseline group differences, however, for HR [F(2,97)=5.8, p<0.01], SK [F(2,86)=7.1, p<0.01] and RR [F(2,63)=5.1, p<0.01]. Compared to controls, both panic groups had higher HR, higher RR and cooler SK, although they did not differ from each other. Because hyperventilation task baselines for HR and SK were highly correlated with overall study baseline values taken prior to the start of the tasks (0.75 and 0.81, respectively), only values from the baseline that occurred before the hyperventilation task were added as covariates. RR was not measured in the overall study baseline and thus hyperventilation baseline values were used as covariates for RR also. During the hyperventilation phase, there was a significant group×time interaction for HR [F(2.6,125.8)=6.3, p<0.01] and CO2 [F(3.4,126.2)=5.8, p<0.01] and a trend toward an interaction for SCL [F(2.8,129.6)=3.9, p<0.05]. We followed the interactions for HR and CO2 by testing simple main effects of group at each time. HR was consistently higher in the two panic groups compared to the control group while hyperventilating, but the two panic groups did not differ from each other (see Fig. 1). There were no group differences in CO2 until the final 30 s of hyperventilating, when the mean value for the control group was higher than that for the other two groups (mean differences: NP vs. control −5.8, p=0.01, DP vs. control −6.6, p<0.01). There were no between-group differences in EMG, SK or RR. Mean differences (natural log transformed): 0–30s: NP vs. control 0.3, p<0.01; ... Fig. 1. Mean differences (natural log transformed): 0–30 s: NP vs. control 0.3, p<0.01; DP vs. control 0.3, p<0.01; 30–60 s: NP vs. control 0.3, p<0.01; DP vs. control 0.3, p<0.01; 60–90 s: NP vs. control 0.4, p<0.01; DP vs. control 0.4, p<0.01. Figure options During the recovery phase, there was a significant group×time interaction on SK [F(3.4,131.4)=5.2, p<0.01]. SK remained fairly constant in the NP and control groups but decreased in the DP group. By the end of the recovery phase, SK was significantly lower for those in the DP group than for those in the NP group, with the control group intermediate and not significantly different from either group. In addition, there was a trend toward a main effect of group for HR [F(2,88)=4.6, p<0.05], with a range of 69–76 beats per min in the two patient groups (which did not differ from each other) as compared with 52–53 beats per min in the control group. There were no differences for EMG, SCL, CO2 or RR. 3.4. Meditative relaxation Self-report: There were group differences in maximum anxiety [F(3,98)=35.9, p<0.001] and average anxiety [F(3,98)=41.3, p<0.001] with anticipatory anxiety used as a covariate. Post hoc testing revealed that NPs had higher scores than DPs, who in turn had higher scores than controls (see Fig. 2). There was also a difference in the number of panic symptoms reported [F(2,96)=8.0, p<0.01] and average symptom intensity [F(2,99)=5.5, p<0.01]. NP reported more panic symptoms and more intense symptoms than controls; DPs were intermediate but did not differ significantly from the other groups (refer to Fig. 2). There was an overall group difference in endorsement of panic attacks during the task (phi=0.31, p=0.01). Separate analysis of the panic groups alone revealed a strong trend (χ2=0.21, p<0.05). Sixteen (33%) NPs, six (15%) DPs and no controls reported panic attacks. Image for figure Fig. 2 Fig. 2. Figure options The groups differed on the RRAQ total score [F(2,97)=20.2, p<0.01]: NPs had higher scores than DPs, who in turn scored higher than controls (see Table 1). To better understand what aspects of relaxation were fear-provoking to participants, we looked at each of the individual items on this questionnaire. In every case, the panic groups reported more fear than the control group. There were only three items, however, that separated nocturnal and day panickers. NPs had higher average scores on “I feel uneasy when I try to relax” (mean difference=1.04, std error=0.24, p<0.01) and “I find it hard to just let go” (mean difference=0.83, std error=0.24, p<0.01). There was a trend for NPs to score higher on “I’m apprehensive when I’m sitting around doing nothing” (mean difference=0.62, std error=0.27, p<0.10). Physiology: Data from the entire relaxation task were analyzed together. There were no group differences for EMG, SCL or HR. There was a trend toward a group×time interaction for SK [F(4.7,168.9)=2.9, p<0.05]. Inspection of the data indicated that SK remained fairly stable throughout the task for the NP and control groups but rose slightly in the DP group. There was a significant main effect of group [F(2,75)=6.7, p<0.01] attributable to higher SK in the control group throughout, averaging 93.1 (SD=4.5) vs. 88.3 (SD=7.1) in the NP group and 87.2 (SD=6.5) in the DP group. These data are presented in Fig. 3. Image for figure Fig. 3 Fig. 3.