A Study of Panic Attacks in University Students of Iran

This study examined the parameters of panic, fear, and avoidance among university students in Iran. Data were collected from 347 students using Farsi translations of the Panic Attack Questionnaire, Beck Depression Inventory, Taylor Manifest Anxiety Scale, State-Trait Anxiety Inventory, and Anxiety Sensitivity Index. Thirty-eight percent of participants reported panic attacks in the past year and 21.4% reported panic attacks in the past 4 weeks when prompted by a broad definition of panic. Men and those with unexpected panic reported greater panic severity whereas women with panic attacks reported greater situational fear and avoidance. Panickers who satisfied DSM-III-R panic disorder (PD) criteria reported greater lifestyle restriction and general psychopathology. The findings provide tentative support for cross-cultural similarity in panic phenomenology and the validity of DSM-III-R PD criteria among university students in Iran. The results are discussed by reference to nonclinical panic research and general themes of Iranian culture.     

Peritraumatic and persistent panic attacks in acute stress disorder

This study examined the prevalence of peritraumatic and persistent panic symptoms following trauma. Survivors of civilian trauma (n=30) with either acute stress disorder (ASD) or no acute stress disorder (non-ASD) were administered the Panic Module of the Structured Clinical Interview for DSM-IV (SCID). Participants also completed the Impact of Event Scale, Acute Stress Disorder Scale, Beck Depression Inventory, Beck Anxiety Inventory, and the Anxiety Sensitivity Index. Panic attacks were experienced by 77% of participants during their trauma, and 47% reported recurrent panic attacks post-trauma. ASD participants demonstrated more panic symptoms during and after their trauma than non-ASD participants. Posttraumatic panic was most strongly associated with anxiety sensitivity. These findings are discussed in terms of cognitive factors that may mediate posttrauma panic and treatment implications for managing posttraumatic anxiety.There is increasing evidence that panic attacks play a role in psychopathological response to trauma. A significant proportion of people with panic disorder report a history of trauma (). Moreover, two-thirds of trauma survivors report panic attacks within the previous 2 weeks (). There is also evidence that people with posttraumatic stress disorder (PTSD) display elevated levels of anxiety sensitivity (). Recent attention has focused on acute panic reactions because of proposals that panic during trauma may condition trauma-related cues to subsequent panic (). There is evidence that panic attacks occur in 53-90% of trauma survivors during the traumatic experience (). Further, people with acute stress disorder (ASD) are more likely to report peritraumatic panic attacks than non-ASD individuals. ASD is a useful framework in which to investigate the role of panic in posttraumatic stress because ASD describes acute responses to trauma that are strongly predictive of chronic PTSD ().This study investigated the relationship between peritraumatic panic and ongoing panic attacks following trauma. Specifically, we indexed panic attacks during trauma and subsequent to trauma in trauma survivors with and without ASD. We also indexed the extent to which distorted interpretations about somatic sensations may be associated with panic attacks following trauma. We considered that the strong evidence that maladaptive appraisals of somatic sensations mediate panic () is directly relevant to posttraumatic panic. We hypothesized that ASD participants would report more peritraumatic and persistent panic than non-ASD participants, and that this panic would be associated with dysfunctional interpretations about somatic stimuli.     

Heart-beat perception, panic/somatic symptoms and anxiety sensitivity in children

There is considerable evidence implicating heart-beat perception (HBP) accuracy and anxiety sensitivity (AS) in the development of panic in adults. However, to date there have been no studies exploring the association between HBP, AS and childhood panic/somatic symptoms. Seventy-nine children aged 8 to 11 years completed a mental tracking paradigm (Psychophysiology 18 (1981) 483) to assess HBP, the Children's Anxiety Sensitivity Index (J Clin Chil Psychol 20 (1991) 162) and the Screen for Childhood Anxiety Related Emotional Disorders (J Am Acad Child Adoles Psych 38 (1999) 1230). Those with good HBP (n = 7, 9%) had significantly higher panic/somatic symptoms (t = -1.71, P < 0.05), and AS (t = -2.16, P < 0.02) than those with poor HBP. There were no effects of age, sex or BMI on HBP. Those with high levels of panic/somatic symptoms were seven times more likely to have good HBP and had AS scores 1 S.D. higher than the remainder of the sample. Multivariate analyses revealed that these two phenotypes had independent associations with high panic/somatic symptoms. These results extend the literature on HBP and panic and suggest that in children, as in adults, increased panic/somatic symptoms are associated with enhanced ability to perceive internal physiological cues, and fear of such sensations.     

Interoceptive fear conditioning as a learning model of panic disorder: an experimental evaluation using 20% CO(2)-enriched air in a non-clinical sample

Despite the role afforded interoceptive fear conditioning in etiologic accounts of panic disorder, there are no good experimental demonstrations of such learning in humans. The aim of the present study was to evaluate the interoceptive conditioning account using 20% carbon dioxide (CO(2))-enriched air as an interoceptive conditioned stimulus (CS) (i.e., physiologically inert 5-s exposures) and unconditioned stimulus (US) (i.e., physiologically prepotent 15-s exposures). Healthy participants (N=42) were randomly assigned to one of three conditions: a CS-only, contingent CS-US pairings, or unpaired/non-contingent CS and US presentations. Electrodermal and self-report (e.g., distress, fear) served as indices of conditioned emotional responding. Results showed greater magnitude electrodermal and evaluative fear conditioning in the paired relative to the CS-only condition. The explicitly unpaired condition showed even greater electrodermal and evaluative responding during acquisition, and marked resistance to extinction. The latter results are consistent with the possibility that the unpaired procedure constituted a partial reinforcement procedure in which CO(2) onset was paired with more extended CO(2) exposure on 50% of the trials. Overall, the findings are consistent with contemporary learning theory accounts of panic.     

Interoceptive Cue Exposure for Depersonalization: A Case Series

Cognitive-behavioral treatment for panic disorder relies heavily on interoceptive exposure. Specifically, therapists induce physical symptoms associated with panic in order to produce habituation to those sensations. Many common symptoms of panic are easily induced, such as increased heart rate and dizziness. However, depersonalization is a difficult symptom to induce in the office. Three uncontrolled cases are presented here where a novel intervention, the use of 3D glasses, was used to successfully induce depersonalization with positive effect. The application of the procedure resulted in rapid habituation within session, and all three patients had significant reductions in panic following treatment. Additional research is necessary to examine the application of this, and other, novel methods for inducing depersonalization as part of a comprehensive approach to treating panic and other psychiatric conditions where depersonalization is present.     

Anticipation of interoceptive threat in highly anxiety sensitive persons

Anticipatory anxiety plays a major role in the etiology of panic disorder. Although anticipatory anxiety elicited by expectation of interoceptive cues is specifically relevant for panic patients, it has rarely been studied. Using a population analogue in high fear of such interoceptive arousal sensations (highly anxiety sensitive persons) we evaluated a new experimental paradigm to assess anticipatory anxiety during anticipation of interoceptive (somatic sensations evoked by hyperventilation) and exteroceptive (electric shock) threat. Symptom reports, autonomic arousal, and defensive response mobilization (startle eyeblink response) were monitored during threat and matched safe conditions in 26 highly anxiety sensitive persons and 22 controls. The anticipation of exteroceptive threat led to a defensive and autonomic mobilization as indexed by a potentiation of the startle response and an increase in skin conductance level in both experimental groups. During interoceptive threat, however, only highly anxiety sensitive persons but not the controls exhibited a startle response potentiation as well as autonomic activation. The anticipation of a hyperventilation procedure thus seems a valid paradigm to investigate anticipatory anxiety elicited by interoceptive cues in the clinical context.     

Avoidance behavior in panic disorder: the moderating influence of perceived control

The relations among anxiety sensitivity, perceived control, and agoraphobia were examined in 239 patients diagnosed with panic disorder (PD). Most patients exhibited agoraphobia accompanying their PD (98% situational avoidance; 90% experiential avoidance; and 80% endorsed interoceptive fear and avoidance). Anxiety sensitivity and perceived emotional control were associated with agoraphobia, and perceived threat control was found to moderate the relationship between anxiety sensitivity and agoraphobia. Lower levels of perceived control were associated with a stronger relationship between anxiety sensitivity and agoraphobia. Results were consistent for self-reported and clinician-rated agoraphobia. Implications for the role of perceived control in agoraphobia development and treatment are discussed.     

Anxiety sensitivity and auditory perception of heartbeat

Anxiety sensitivity (AS) is the fear of sensations associated with autonomic arousal. AS has been associated with the development and maintenance of panic disorder. Given that panic patients often rate cardiac symptoms as the most fear-provoking feature of a panic attack, AS individuals may be especially responsive to cardiac stimuli. Consequently, we developed a signal-in-white-noise detection paradigm to examine the strategies that high and low AS individuals use to detect and discriminate normal and abnormal heartbeat sounds. Compared to low AS individuals, high AS individuals demonstrated a greater propensity to report the presence of normal, but not abnormal, heartbeat sounds. High and low AS individuals did not differ in their ability to perceive normal heartbeat sounds against a background of white noise; however, high AS individuals consistently demonstrated lower ability to discriminate abnormal heartbeats from background noise and between abnormal and normal heartbeats. AS was characterized by an elevated false alarm rate across all tasks. These results suggest that heartbeat sounds may be fear-relevant cues for AS individuals, and may affect their attention and perception in tasks involving threat signals.     

Animal phobias versus claustrophobias: Exteroceptive versus interoceptive cues

The overall purpose of this investigation was to examine heterogeneity among specific phobias. In particular, the goals were to compare features of fear responding between individuals fearful of claustrophobic situations and individuals fearful of spiders/snakes, and to compare their response to hyperventilation challenges. By so doing, specific predictions were tested in relation to a conceptual model of exteroceptive and interoceptive fear cues. Using a nonclinical sample, 19 subjects with spider/snake phobias, 18 nonphobies, and 9 subjects with claustrophobias were exposed on two separate occasions to a live tarantula or python, a small closet, and a hyperventilation challenge. Dependent measures included subjective anxiety, panic attacks, physical symptoms, cognitive symptoms (or, fear of symptoms) and heart rate. In addition, subjects completed a standardized self-report scale that measures fear of bodily symptoms of arousal. It was found that subjects with claustrophobia reported more physical symptoms and cognitive symptoms than did subjects with snake/spider phobias, in response to their fear-relevant stimulus. In addition, claustrophobic subjects were more fearful of hyperventilation challenges and reported more fear of bodily symptoms, than did snake/spider phobic subjects. Finally, subjects with claustrophobia were as fearful of hyperventilation as they were of their fear-relevant stimulus. Theoretical and empirical implications of these findings are discussed.     

The facilitative effects of heart-rate feedback in the emotional processing of claustrophobic fear

This study examines predictions derived from Foa and Kozak's theory of emotional processing. We hypothesized that the provision of heart-rate feedback would facilitate emotional processing through a fuller activation of the participant's fear structure, and by focusing participants' attention on information that is incompatible with the fear structure, i.e., the interoceptive pattern of habituation. Nonclinical students (N = 54) showing marked claustrophobic fear received 30 min of self-directed exposure to a claustrophobic chamber. Three exposure conditions (heart-rate feedback, paced-tone control, and exposure only control) were examined across six 5-min exposure trials. Participants receiving heart-rate feedback displayed greater between-trial habituation across treatment trials and lower levels of fear at post-treatment. Treatment process findings failed to support the fear activation hypothesis. Implications of the findings for theories of fear reduction are discussed.     

Interoceptive fear conditioning and panic disorder: the role of conditioned stimulus-unconditioned stimulus predictability

Interoceptive fear conditioning is at the core of contemporary behavioral accounts of panic disorder. Yet, to date only one study has attempted to evaluate interoceptive fear conditioning in humans (see Acheson, Forsyth, Prenoveau, & Bouton, 2007). That study used brief (physiologically inert) and longer-duration (panicogenic) inhalations of 20% CO(2)-enriched air as an interoceptive conditioned (CS) and unconditioned (US) stimulus and evaluated fear learning in three conditions: CS only, CS-US paired, and CS-US unpaired. Results showed fear conditioning in the paired condition, and fearful responding and resistance to extinction in an unpaired condition. The authors speculated that such effects may be due to difficulty discriminating between the CS and the US. The aims of the present study are to (a) replicate and expand this line of work using an improved methodology, and (b) clarify the role of CS-US discrimination difficulties in either potentiating or depotentiating fear learning. Healthy participants (N=104) were randomly assigned to one of four conditions: (a) CS only, (b) contingent CS-US pairings, (c) unpaired CS and US presentations, or (d) an unpaired "discrimination" contingency, which included an exteroceptive discrimination cue concurrently with CS onset. Electrodermal and self-report ratings served as indices of conditioned responding. Consistent with expectation, the paired contingency and unpaired contingencies yielded elevated fearful responding to the CS alone. Moreover, adding a discrimination cue to the unpaired contingency effectively attenuated fearful responding. Overall, findings are consistent with modern learning theory accounts of panic and highlight the role of interoceptive conditioning and unpredictability in the etiology of panic disorder.     

Specificity of interoceptive fear to panic disorders

It has been argued that fear of interoceptive sensations is a maintaining factor in panic disorders. This study investigated whether interoceptive fears are specific to panic disorders or whether they are a feature of neurosis in general. Twenty-nine panic patients, 28 nonpanicking neurotic controls, and 29 normal controls were compared for their scores on a 14-item questionnaire intended to measure interoceptive fears. Indeed it was found that panic patients scored considerably higher than both control groups, whereas no significant differences emerged between the two control groups. It is concluded that interoceptive fear is diagnostically specific to panic disorders.This study was partly supported by the Dutch Organization for Fundamental Research (ZWO/Psychon., 560-268-001) and was carried out at the unit for clinical behavior therapy at Vijverdal Mental Hospital, Maastricht, The Netherlands.     

Waning of panic sensations during prolonged hyperventilation

Recent theories about panic emphasize that a hyperventilatory positive feedback loop is involved in panic: catastrophic misinterpretation of bodily sensations may trigger anxiety, anxiety may stimulate hyperventilation, hyperventilation may promote the salience of feared sensations etc. Such models leave unexplained how and when panics come to an end. It was hypothesised that panic with hyperventilation may end because pronounced hyperventilation becomes, in the course of time, less powerful in generating perceivable bodily sensations. Twenty healthy subjects hyperventilated forcefully and experienced clear panic symptoms as defined by DSM IIIR. When pCO2 was kept 55% below base line for 90 min, panic symptoms waned. The mean intensity of the symptoms declined as did the number of symptoms occurring. No panic symptoms were observed in the control group (n = 20) who ventilated normally. In so far as hyperventilation is involved in the positive feedback loops that characterize panic, panic attacks may be time-limited because sensations induced by hyperventilation become less salient even if massive hyperventilation continues. As to the explanation of the reported phenomenon, it is suggested that, apart from habituation, local physiological changes due to prolonged hyperventilation may produce a decrease in interoceptive input.     

Responses to symptom induction exercises in panic disorder

Exposure to panic symptoms (interoceptive exposure) is often included as part of treatment for panic disorder (PD), although little is known about the relative effects of particular symptom induction exercises. This study describes responses of individuals with PD and nonclinical controls to 13 standard symptom induction exercises and 3 control exercises. Generally, individuals with PD responded more strongly to symptom induction exercises than did controls. The exercises producing the most fear included spinning, hyperventilation, breathing through a straw, and using a tongue depressor. This study also reports findings regarding specific symptoms triggered by each exercise, the percentage of participants reporting fear during each exercise, and predictors of fear.     

Interoceptive Exposure Therapy Combined with Trauma‐related Exposure Therapy for Post‐traumatic Stress Disorder: a Case Report

Trauma‐related exposure therapy is a useful but not universally effective treatment for post‐traumatic stress disorder. Anxiety sensitivity may play an important role in this disorder, as it does in panic disorder. Studies have shown that interoceptive exposure therapy reduces anxiety sensitivity in panic disorder. The present case study was a preliminary investigation of the merits of including interoceptive exposure therapy in the treatment of post‐traumatic stress disorder, in order to improve treatment outcome for a patient who had no history of panic disorder or panic attacks. Interoceptive exposure therapy (4 sessions) was one component of treatment, combined with trauma‐related exposure therapy (4 sessions of imaginal exposure followed by 4 sessions of in vivo exposure). Treatment outcome was assessed with the Clinician‐Administered Post‐traumatic Stress Disorder Scale, a self‐report measure of post‐traumatic stress disorder symptoms, and measures of symptoms and cognitions commonly associated with post‐traumatic stress disorder. Scores on all outcome measures decreased over the course of treatment, with gains maintained at 1‐ and 3‐month follow‐up. Symptoms of anxiety sensitivity and post‐traumatic stress disorder decreased during interoceptive exposure therapy. The results indicate that interoceptive exposure therapy is a promising adjunctive intervention for post‐traumatic stress disorder. Further research is needed into the merits of combining interoceptive exposure therapy and trauma‐related exposure therapy as a means of boosting treatment efficacy.     

Evaluation of a brief aerobic exercise intervention for high anxiety sensitivity

Anxiety sensitivity, or the belief that anxiety-related sensations can have negative consequences, has been shown to play an important role in the etiology and maintenance of panic disorder and other anxiety-related pathology. Aerobic exercise involves exposure to physiological cues similar to those experienced during anxiety reactions. The present study sought to investigate the efficacy of a brief aerobic exercise intervention for high anxiety sensitivity. Accordingly, 24 participants with high anxiety sensitivity scores (Anxiety Sensitivity Index-Revised scores >28) were randomly assigned to complete either six 20-minute sessions of aerobic exercise or a no-exercise control condition. The results indicated that individuals assigned to the aerobic exercise condition reported significantly less anxiety sensitivity subsequent to exercise, whereas anxiety sensitivity scores among non-exercisers did not significantly change. The clinical research and public health implications of these findings are discussed, and several potential directions for additional research are recommended.     

Anxiety sensitivity and panic attacks in a nonclinical population

In the present study, we administered the Anxiety Sensitivity Index (ASI) and a modified version of the Panic Attack Questionnaire (PAQ) to 425 college students to determine whether high anxiety sensitivity ('fear of fear') occurs in the absence of a history of unpredictable ('spontaneous') panic attacks, or whether such attacks are a necessary precursor to high anxiety sensitivity. Based on their ASI scores, subjects were assigned to either the high, medium, or low anxiety sensitivity groups. High anxiety sensitivity subjects more frequently reported both a personal and family history of panic than did subjects in the other groups. Nevertheless, two-thirds of the high anxiety sensitivity subjects had never experienced an unpredictable panic attack. This suggests that the fear of anxiety can be acquired in ways other than through personal experience with panic.     

Associations between emotional avoidance,anxiety sensitivity,and reactions to an observational fear challenge procedure

Research has shown that emotional avoidance and anxiety sensitivity are associated with more self-reported fear and distress in response to laboratory fear challenge procedures. The present study aimed to expand upon this work and examined how emotional avoidance and anxiety sensitivity are related to emotional and physiological responses to an observational fear challenge procedure. To accomplish this aim, a carefully screened, non-clinical sample (N = 43) was administered the Acceptance and Action Questionnaire (AAQ), a measure of emotional avoidance, and the Anxiety Sensitivity Index (ASI). Participants then engaged in an observational fear challenge paradigm. During the fear challenge, participants watched mock panic attacks while emotional (e.g., fear and panic) and skin conductance levels were assessed. Consistent with expectation, emotional avoidance and anxiety sensitivity were positively associated with more self-reported fear and more severe panic symptoms to the challenge procedure. However, anxiety sensitivity was more highly associated with self-reported fear and panic symptoms in response to the challenge procedure than emotional avoidance. Emotional avoidance and anxiety sensitivity were not associated with levels of physiological arousal to the observational fear challenge procedure. Discussion focuses on the interplay between emotional avoidance, anxiety sensitivity, and the development of vicarious fear responses and how these constructs may contribute to the pathogenesis of anxiety disorders.     

Categorical or Dimensional: A Reanalysis of the Anxiety Sensitivity Construct

Anxiety sensitivity, or the fear of anxiety sensations, has been implicated in the etiology of anxiety disorders, particularly panic disorder. Recently, inconsistent findings have been reported regarding the latent structure of anxiety sensitivity. Whereas some taxometric studies of anxiety sensitivity have reported evidence of categorical latent structure, others have found evidence of a latent dimension. The purpose of the present research was to further examine the latent structure of anxiety sensitivity using taxometric procedures and commonly utilized measures of anxiety sensitivity. To this end, three mathematically independent taxometric procedures (MAXEIG, MAMBAC, and L-Mode) were applied to data collected from two large nonclinical samples (n's = 1,171 and 2,173) that completed the Anxiety Sensitivity Index and the Anxiety Sensitivity Index-Revised. Results from both studies converged in support of a dimensional conceptualization of anxiety sensitivity. A third study was conducted using indicators derived from the newly revised Anxiety Sensitivity Index-3 in a separate sample of 1,462 nonclinical participants. Results of these analyses provided further support for a dimensional anxiety sensitivity solution. The implications of these results for anxiety sensitivity research are discussed, and several potential directions for future research are considered.