Anxiety sensitivity, defined as the fear of anxiety-related sensations and their consequences (Reiss & McNally, 1985), has been consistently shown to be associated with risk for anxiety psychopathology as well as other mental health problems. The primary objective of the present secondary prevention trial sought to examine strategies to reduce anxiety sensitivity among persons with elevated anxiety sensitivity by testing the singular and combined efficacy of two commonly used strategies in multi-component interventions for reducing anxiety sensitivity: (a) anxiety psychoeducation emphasizing the benign nature of stress and (b) interoceptive exposure (i.e. repeated inhalations of 35% CO₂ gas mixture). To provide a stringent control for non-specific effects associated with anxiety psychoeducation and interoceptive exposure with CO₂, two control strategies were included in the study design: general health and nutrition education and repeated inhalations of regular room air. Utilizing a 2X2 design, participants were randomly assigned to receive an education component and intervention sessions consisting of one of two gas mixtures. The current study did not support the relative efficacy of hypothesized active intervention strategies. Rather, all conditions led to significant reductions in anxiety sensitivity. In addition, within-condition effect sizes for conditions in the present study were comparable to effect sizes of active interventions that were efficacious in previous research. Findings from the present study support that anxiety sensitivity is malleable following brief, cost-efficient interventions and these reductions are maintained over a one-month follow-up period. Data from the present study suggest that in the presence of stringent control conditions, hypothesized active intervention strategies provided little additional benefit. The present study has implications for methodological considerations for future secondary prevention trials for the reduction of anxiety sensitivity. The absence of stringent control groups might lead to premature conclusions that reductions in anxiety sensitivity are due to the specific effects of active interventions. Further research is needed to elucidate specific effects of intervention strategies for the reduction of anxiety sensitivity in at risk populations in order to refine secondary prevention interventions aimed to reduce risk for psychopathology. / text