Subjective and physiological responses to the 35% carbon dioxide challenge in healthy and non-clinical control populations: a meta-analysis and systematic review

Background/Rationale: The carbon dioxide (CO₂) challenge has been reliably used in laboratory settings as a panicogen in clinical populations. However, the magnitude of these effects on healthy and non-clinical control populations are not clear. The aim of this meta-analysis and systematic review is to provide quantitative estimates of those effects. Specifically, the current paper will evaluate the relative efficacy of the CO₂ challenge in eliciting both subjective and physiological arousal in healthy and non-clinical control populations.

Method: A total of 16 articles with 35 independent samples were included in the meta-analysis, while 37 studies with 74 independent samples were included in the systematic review.

Results: Both the meta-analysis and systematic review found the CO₂ challenge to elicit an increase in subjective distress via self-reported anxiety and fear. Physiological responses via blood pressure and heart rate were heterogeneous in studies sampled, with no significant changes observed across studies. Moderator analyses revealed the variations in findings may be attributed to participant screening and invasive sampling.

Discussion: Findings highlight the CO₂ challenge as a useful tool in the provocation of subjective distress. Implications for both the use of the CO₂ challenge and its anticipated effects in healthy and non-clinical control populations are discussed.     

Understanding the impact of attachment insecurity on PTSD symptoms among male Veterans and military personnel

ABSTRACT

Attachment insecurity (i.e., attachment anxiety and attachment avoidance) has been found to contribute to PTSD symptom severity in Veterans. However, little is known of the unique contribution of attachment insecurity on individual PTSD symptom clusters. In a community sample of 106 combat-deployed Veterans, active duty service members, and reservists, this study examined: (1) the relationships between childhood family experience, combat experience, attachment insecurity, and PTSD symptom clusters, and (2) the influence of attachment insecurity on PTSD symptom clusters. Results revealed significant correlations between attachment anxiety and all PTSD symptom clusters (rs = .22 –.43) and attachment avoidance and PTSD symptom clusters, except the avoidance cluster (rs = .21 ?.36). Four multiple regression analyses were employed to address the second study aim. Childhood family experiences predicted negative alterations in cognitions and mood (β = –.30) and alterations in arousal and reactivity (β = –.20). Further, combat experience significantly predicted each symptom cluster of PTSD (βs = .03 –.44). In the second step, attachment anxiety and attachment avoidance were added to each model. Attachment anxiety and attachment avoidance predicted negative alterations in cognitions and mood (βs = .22 and .35) and alterations in arousal and reactivity (βs = .27 and .17). Inconsistent with previous research, attachment insecurity did not predict symptoms of avoidance. These results highlight the impact of attachment among a diverse sample of trauma exposed individuals and may provide insights for clinical implications and therapeutic approaches when working with Veterans and military personnel high in attachment insecurity.     

A preliminary typology of organisational response to allegations of workplace bullying: see no evil, hear no evil, speak no evil

Organisational representative response is an important factor to consider when counselling employees who have experienced bullying and are considering approaching their organisation for assistance. The author argues that not all responses are supportive and that some responses can further harm an employee. The author presents a review of representative responses, developed from bullying cases the author saw as a counsellor or trainer. The author reviews three organisational representative responses to allegations of bulling: (1) the behaviour is acceptable; (2) the behaviour is inappropriately equally attributed to both parties as a personality conflict; and (3) the behaviour is harmful and inappropriate. The author concludes that counsellors must review potential organisational representative responses with employees and recommends mandatory training for organisational representatives.     

Carryover bias in visual assessment.

Carryover of stimuli in sequential judgments was studied for a visual assessment task involving estimation of the percentage cover of black circles on a white image. Seven image types with different levels of cover density were arranged in a sequentially balanced design in which each image type was preceded the same number of times by all image types. In the absence of carryover, when images were preceded by images with the same cover density, the response scores were well fitted by a power function of percentage cover with a mean exponent of 0.73 over subjects. Carryover took the form of an assimilation, so that the cover estimate for a target image was generally higher when preceded by an image with higher cover, and lower when preceded by an image with lower cover. However, the magnitude of the carryover effect showed little evidence of increasing with difference in cover between successive images. Nonparametric and parametric methods for testing for carryover are presented. The need for development of psychological models to explain the proposed statistical models is discussed.