The carbon dioxide (CO2) challenge paradigm has been useful for modeling panic in the laboratory. While showing promise as a technique able to promote a better understanding of the etiology of panic disorder (PD), this goal has been impeded by the lack of standardization of the challenge methodology and by uncertainty concerning the optimal definition and assessment of laboratory panic. The purpose of this paper is to highlight the impact of method variance on laboratory findings and to present recommendations for future challenge research. We begin by reviewing studies that have employed CO2 as a stimulus for panic provocation focusing on the status of key methodological parameters between the studies and the relationship of these parameters to findings. We then make pragmatic and theoretically-based recommendations concerning approaches to methodological standardization, the establishment of a valid laboratory panic definition and the desirability of using of additional outcome measures. We conclude that although further work is needed to improve the CO2 challenge laboratory model of panic, this paradigm can play an important role in understanding the psychopathology of PD.
Bibliographical noteFunding Information:
Preparation of this article was supported by National Institute of Alcohol Abuse and Alcoholism Grant R29-AA09871, awarded to the second author, and by National Institute of Mental Health Training Grant MH-17069, awarded to the first author.
- Anxiety disorder
- Carbon dioxide challenge
- Panic disorder