Biomedical subjects

J C Shipherd

Publications and source records attributed to J C Shipherd.

9 recordsLinked to original sources

PubMed2001

Specificity of Stroop interference in patients with pain and PTSD.

The authors investigated processing of threat words in motor vehicle accident survivors using a modified Stroop procedure. Three samples were included: 28 participants with comorbid posttraumatic stress disorder (PTSD) and pain, 26 participants with pain without PTSD, and 21 participants without pain or any psychiatric conditions. Four word categories were used: (a) accident words, (b) pain words, (c) positive words, and (d) neutral words. This study examined whether processing biases would occur to accident words only in participants with PTSD or if these biases would also be noted in the No PTSD/Pain sample. Additionally, this study examined whether processing biases would be noted to pain words in the 2 pain samples, irrespective of PTSD. Overall, color naming was significantly slower in the PTSD/Pain group in comparison with the other groups. As well, the PTSD/Pain sample showed significant response delays to both accident and pain-related words, whereas patients with No PTSD/Pain showed delays to pain stimuli only.

Adult↗

PubMed1999

The effects of suppressing trauma-related thoughts on women with rape-related posttraumatic stress disorder.

A hallmark symptom of posttraumatic stress disorder (PTSD) is the presence of intrusive thoughts that come to mind against an individual's will and are frequently accompanied by considerable distress. This investigation examined the effects of deliberate suppression of rape-related thoughts on female sexual assault survivors, in order to explore this facet of PTSD. Seventeen women with chronic PTSD following a sexual assault were contrasted with nineteen survivors without PTSD, using a thought suppression paradigm (e.g. [Wegner, Schneider, Carter, & White (1987) Paradoxical effects of thought suppression. Journal of Personality and Social Psychology, 53 5-13]). Results indicated that PTSD participants experienced a rebound in the frequency of rape-related thoughts following deliberate suppression, whereas non-PTSD participants did not experience a rebound. Reported level of perceived controllability over rape-related thoughts for the PTSD participants was significantly lower during the suppression phase (as compared with the expression phase) relative to the non-PTSD participants. PTSD participants were significantly more anxious, depressed and distressed throughout the procedure relative to non-PTSD participants, although mood changes did not parallel the rebound effect found with rape-related thoughts in the PTSD group. Results are discussed in light of the role that intrusive thoughts may play in the maintenance of PTSD.

Adolescent↗

PubMed1999

Response patterns to repeated CO2 inhalation in individuals with high anxiety sensitivity.

The present report extends previous work which has documented two distinct response patterns to repeated presentation of interoceptive cues (using CO2 inhalation) in PD patients [Beck, J. G. & Shipherd, J. C. (1997). Repeated exposure to interoceptive cues: does habituation of fear occur in panic disorder patients? Behaviour Research and Therapy, 35, 551-557]. We were interested in determining if these two patterns of fear habituation and sensitization would be noted in panic-naive individuals who reported high levels of Anxiety Sensitivity. A second aspect of this report examined whether attention to bodily sensations versus to neutral material would impact fear habituation and sensitization. Participants included 43 panic-naive individuals who scored at least 1 standard deviation above norms on the Anxiety Sensitivity Index. Results indicated that 37% of the sample reported habituation of fear, 47% reported fear sensitization and 16% demonstrated relatively stable fear levels across 12 inhalations of CO2 during session 1. The attentional manipulation did not exert a pronounced influence on anxiety, panic symptom severity, skin conductance, or heart rate in either Habituators or Sensitizers during session 2. These results are discussed in light of their relevance in understanding fundamental psychopathological processes underlying Panic Disorder.

Adult↗

PubMed1999

Exaggerated anxiety is not unique to CO2 in panic disorder: a comparison of hypercapnic and hypoxic challenges.

Current biological models of panic disorder (PD) assert that this disorder is maintained by hypersensitivity to carbon dioxide (CO2) and related asphyxia cues, which is manifested as an exaggerated suffocation alarm (D. Klein, 1993). Because suffocation can result from both increased CO2 (hypercapnia) and decreased oxygen (O2; hypoxia), this study examined respiratory responding and anxiety during 5% CO2 (a hypercapnic challenge) and 12% O2 (a hypoxic challenge) in 14 PD patients and 14 matched controls (MC). Results demonstrate that irrespective of the source of suffocation, PD patients respond with increased anxiety relative to MC participants. Significant group differences were observed in respiratory functioning, with the PD patients showing higher respiratory rates in response to both challenges. The MC sample demonstrated the expected respiratory responses to both hypercapnia and hypoxia. The findings indicate that PD patients are hypersensitive to alterations in breathing and that this reactivity is not specific to CO2.

Adult↗

PubMed1997

Repeated exposure to interoceptive cues: does habituation of fear occur in panic disorder patients? A preliminary report.

In order to explore the mechanism of action of interoceptive exposure, 12 Panic Disorder (PD) patients were presented with two sessions of repeated CO2 inhalation. Two distinct patterns of responding were noted. The first pattern was described as habituation of fear (n = 6). These patients showed decrements in pre- and post-inhalation anxiety during both sessions (with more rapid decline during session 2), as well as spontaneous recovery of fear at the onset of session 2. The second pattern indicated fear sensitization. These patients showed relatively low levels of anticipatory anxiety preceding CO2 inhalation during both sessions but reported robust increases in fear following gas inhalation. The extent of this increase was slightly less during session 2 relative to session I and did not appear to be mediated by cardiovascular arousal, as both groups showed rapid HR habituation during both sessions. Results are discussed in light of current theories of PD and its treatment.

Administration, Inhalation↗

PubMed1996

Fearful responding to repeated CO2 inhalation: a preliminary investigation.

In an effort to explore factors which maintain fear of physical sensations, repeated administration of 35% CO2 was used with college students scoring high and low on the Anxiety Sensitivity Index. Half of each group was administered 12 CO2 trials, while the other half received 9 CO2 trials, followed by a dishabituation trial (Trial 10) and 2 more CO2 administrations (Trials 11 and 12). Measures included subjective anxiety, heart rate, skin conductance, and number of panic symptoms reported. Results indicated a nonsignificant trend for the High ASI group to show increased pre-inhalation anxiety across trials, while the Low ASI group showed a rapid reduction in pre-inhalation anxiety. Post-inhalation skin conductance mirrored this pattern, although rapid reduction in post-inhalation heart rate was observed. Overall, the High ASI participants showed a notable lack of fear reduction across trials. Results are discussed in light of sensitization as a factor contributing to anticipatory anxiety, with implications for understanding the etiology and maintenance of Panic Disorder.

Adult↗

PubMedDate not supplied

Relationships between the anxiety sensitivity index, the suffocation fear scale, and responses to CO2 inhalation.

Interest in documenting ways to predict anxious responding in panic disorder (PD) patients has proliferated recently in the literature. In the current study, two self-report measures were assessed to determine their relative utility in predicting responses to a panicogenic challenge. The Anxiety Sensitivity Index (ASI) and the Suffocation Fear Scale (SFS) were evaluated by correlating scores on these measures with reactions to inhalation of 35% carbon dioxide (CO2), assessed via anxiety ratings, panic symptom intensity, tidal volume (VT) and respiratory rate (RR). A sample of 14 PD patients and 14 matched control (MC) participants demonstrated that the relationship between ASI scores and responses to 35% CO2 were stronger than the relationship between SFS scores and responses to CO2. Specifically, both respiratory responses (VT and RR) and self-reported reactions (anxiety and symptom intensity) were significantly correlated with scores on the ASI. In contrast, scores on the SFS were significantly correlated with only one measure of respiratory change (VT). Although preliminary, these data indicate that the ASI may be a more useful tool than the SFS in predicting self-reported and respiratory responses to CO2 challenges.

Adult↗

PubMedDate not supplied

How does interoceptive exposure for panic disorder work? An uncontrolled case study.

To examine the influence of interoceptive exposure (IE) when used alone in the treatment of Panic Disorder (PD), 17 PD patients were presented with six IE sessions, using 35% CO2 as the exposure medium. The data indicate that IE alone is effective in reducing panic, panic-related fears, and general anxiety. However, the positive effects of IE do not appear to extend to agoraphobia, related fears, or depressed mood. Two distinct within-session patterns of fear response to IE were noted, one indicating habituation and the other indicating a lack of fear reduction. Although both patterns were associated with reductions in panic and anxiety following IE, the Habituators appeared to have a more positive outcome, which occurred more rapidly. These data suggest that IE may operate via two different pathways. Implications for understanding fear reduction are discussed, along with directions for future study.

Administration, Inhalation↗

PubMedDate not supplied

Do panic symptom profiles influence response to a hypoxic challenge in patients with panic disorder? A preliminary report.

OBJECTIVE: This study examined how panic symptom profiles affect response to a hypoxic laboratory challenge in patients with panic disorder. METHODS: Seven patients whose naturally occurring panic attacks were characterized by prominent respiratory symptoms (Resp subgroup) were compared and contrasted with seven patients who did not report respiratory symptoms during panic attacks (NonResp subgroup). All were administered a novel 12% O2 challenge and assessed with measures of tidal volume, respiratory rate, end-tidal CO2, anxiety, and panic symptoms. RESULTS: Although the Resp and NonResp subgroups showed equivalent increases in anxiety and panic symptoms, the Resp subgroup showed greater fluctuation in tidal volume during and after the challenge as well as overall lower levels of end-tidal CO2. CONCLUSIONS: Our results suggest the importance of panic symptom profiles in determining respiratory responses to a hypoxic challenge in patients with panic disorder. These findings are discussed in light of current theories of panic disorder, with particular attention to respiratory disturbances in this disorder.

Adult↗