نقش واسطه ای حساسیت اضطراب در هراس از پرواز

Anxiety sensitivity (AS) is the tendency to interpret anxiety-related bodily sensations in a threatening way. Previous research in a subclinical population identified AS as a vulnerability factor in flight phobia: AS moderates the relationship between somatic sensations and flight anxiety. The present study aimed at gaining further evidence for the moderational role of AS in a large clinical population with flight phobia. The data were obtained from 103 participants: 54 flight phobic participants and 49 controls. Just before taking a flight participants were asked to complete the Anxiety Sensitivity Index and to report their level of anxiety and bodily sensations. Results showed that AS moderates the relationship between somatic sensations and flight phobia: somatic sensations significantly predicted flight anxiety in subjects with higher AS scores, while this was not the case for subjects scoring lower on AS. Present findings implicate that treatment protocols should be supplemented by interventions specifically aimed at reducing AS, especially for individuals high in AS.

With civil aviation establishing itself as a growing industry, traveling by airplane has become a part of day-to-day life. But not for some: 10–30% of the general population has flight phobia (Van Gerwen, Spinhoven, Diekstra, & VanDyck, 1997), or in other words a fear of flying. Most research efforts have focused on investigating the effects of treatment of this particular phobia. However, in order to set up effective treatment interventions, knowledge of the underlying mechanisms can be crucial. The current study aims at clarifying the role of anxiety sensitivity in flight phobia. Taking a flight can produce a number of bodily sensations due to specific factors associated with the flying environment, like for example acceleration (Jaffee, 2005), pressure changes (Harding & Mills, 1983) and turbulence (Jaffee, 2005). Also, changes in the partial pressure of oxygen can lead to a condition called hypoxia (Mortazavi, Eisenberg, Langleben, Ernst, & Schiff, 2003). Hypoxia is an oxygen deficiency at a cellular level, meaning there is a low oxygen saturation in the blood. Humphreys, Deyermond, Bali, Stevenson, and Fee (2005) found that more than half of aircraft passenger have an oxygen saturation of 94% or lower, this is a level where, at sea level, one would be administered supplemental oxygen. Symptoms of hypoxia include shortness of breath, heart racing, and dizziness, which are strikingly similar to the bodily correlates of fear. Analogous to the panic model of Clark (1999) it would thus be possible that the aversive sensations caused by hypoxia are misinterpreted as signs fear and panic. Clark proposed that panic attacks are caused by the catastrophic misinterpretation of bodily symptoms. Such misinterpretation leads to fear which in turn leads to more bodily sensations, eventually resulting in a vicious cycle. Anxiety sensitivity (AS) is thought essential to his vicious cycle. Anxiety sensitivity is the tendency to interpret anxiety-related bodily sensations as threatening (Reiss, 1991). AS has most commonly been associated with PD (McNally, 2002 and Taylor, 1995): studies in non-clinical samples have shown that elevated AS is associated with the incidence of panic attacks, moreover, studies in clinical samples have shown that AS is greater in PD than in other anxiety disorders. However, elevated AS levels have been found in others types of anxiety disorders. A recent meta-analytic review by Naragon-Gainey (2010) has shown that AS is most strongly related to PD, Generalized Anxiety Disorder (GAD) and Post-Traumatic Stress Disorder (PTSD). Social Anxiety, Agoraphobia and OCD are moderately related to ASI. Specific phobia has the weakest link with AS, although it can still be elevated. Interestingly, only fear of confinement (claustrophobia) and fear of bodily harm were related to AS, while fear of blood/injection/injury and animal phobias were not. However, Rivas and Tortella-Feliu (2000) have demonstrated an association between fear of flying and elevated levels of anxiety sensitivity: an elevated AS was found among individuals with fear of flying and moreover, a higher intensity of the fear of flying was associated with a higher AS. Moreover, in a previous study we have explored the specific role of AS as a vulnerability factor in fear of flying, in the sense that anxiety sensitivity moderates the relationship between somatic sensations and flight anxiety (Vanden Bogaerde & De Raedt, 2008). About 160 student participants were asked to complete the Flight Anxiety Situations Questionnaire, the Flight Anxiety Modality Questionnaire (Van Gerwen, Spinhoven, Van Dyck, & Diekstra, 1999) and the Anxiety Sensitivity Index (Vancleef, Peters, Roelofs, & Asmundson, 2006). Results showed that the relationship between somatic sensations and in-flight anxiety is stronger for people with higher anxiety sensitivity than for people with lower anxiety sensitivity, indicating that AS is, as hypothesized, a moderator in fear of flying. In order to gain more evidence about the role of anxiety sensitivity in flight phobia, some issues needed to be addressed. First, the previous findings were based on a non-clinical population. Second, measurement of flight anxiety and somatic sensations relied solely on questionnaire data that was gathered in an non-anxious situation. The present study aimed at gaining additional evidence for the moderational role of anxiety sensitivity in flight phobia. Therefore, the present study was based on a clinical and a healthy control sample. Additionally, in this study we included measurements of somatic sensations and flight anxiety just before participants took a flight to ensure ecological validity of the measurements. Generally, we expect AS levels to be higher in flight phobic subjects than in controls. More specifically, the hypothesis is that AS moderates the relationship between somatic sensations and flight anxiety: individuals with higher AS will respond more anxiously to somatic symptoms than individuals with lower AS, presence of (higher levels of) AS thus strengthens the relationship between somatic sensations and flight anxiety, indicating might function as a vulnerability factor.

In order to verify that both groups differed significantly in flight anxiety, independent samples t-tests were conducted on all scales of the diagnostic questionnaires FAS and FAM (general). The results showed that both groups differed on all scales (see Table 2): flight phobics scored significantly higher on all subscales. Table 2. FAS and FAM scores of flight phobic and control group. Flight phobics Controls t df p M SD M SD FAS Anticipation 42.61 12.148 12.77 2.573 17.606 58.424 <.001 In flight 41.37 7.965 13.23 3.528 23.450 75.180 <.001 Association 14.26 5.540 7.21 .778 9.234 55.399 <.001 Total 109.85 23.806 36.45 6.286 21.802 61.377 <.001 FAM Somatic 30.15 14.535 12.11 2.369 8.981 56.292 <.001 Cognitive 27.78 8.661 8.02 2.427 16.040 62.593 <.001 Table options 2.2. The role of anxiety sensitivity First, an independent groups t-test was performed to detect group differences in the level of anxiety sensitivity (AS) between the flight phobic and control group. Because Levene's test for equality of variances was significant, we used the tests for ‘equal variances not assumed’. Results showed that there was a significant difference between groups with flight phobics reporting much higher levels of AS than controls. Also, there were significant differences between the anxiety (VAS) and somatic sensations (FAM Somatic subscale). Means, standard deviations and the t-tests of these variables are described in Table 3.