FEARFUL RESPONDING TO REPEATED CO2 INHALATION - A PRELIMINARY INVESTIGATION

In an effort to explore factors which maintain fear of physical sensat ions, repeated administration of 35% CO2 was used with college student s 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 C O2 administrations (Trials 11 and 12). Measures included subjective an xiety, heart rate, skin conductance, and number of panic symptoms repo rted. 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-inh alation skin conductance mirrored this pattern, although rapid reducti on in post-inhalation heart rate was observed. Overall, the High ASI p articipants showed a notable lack of fear reduction across trials. Res ults are discussed in light of sensitization as a factor contributing to anticipatory anxiety, with implications for understanding the etiol ogy and maintenance of Panic Disorder. Copyright (C) 1996 Elsevier Sci ence Ltd