This study tests whether a single session of exposure therapy may be enhanced by the addition of anti-phobic actions beyond the mere fading of safety behaviors. A total of 100 acrophobic participants will be randomly assigned to receive standard exposure therapy (EXP), exposure therapy with safety behavior fading (EXP + SBF), exposure with safety behavior fading and anti-phobic actions (EXP + SBF + AA), or to a wait-list control group (WL).

This study tests whether a single session of exposure therapy may be enhanced by the addition of one of two augmentation strategies, including engagement in anti-phobic actions and fading of safety behaviors. Because utilization of safety behaviors is functionally precluded by anti-phobic action, the present study design will both replicate and extend prior research by addressing whether anti-phobic actions enhance exposure therapy beyond the mere fading of safety behaviors. A total of 100 individuals between the ages of 18 and 65 meeting DSM-IV criteria for acrophobia (fear of heights) will be randomly assigned to one of four conditions including (1) standard exposure therapy, (2) exposure therapy with safety behavior fading, (3) exposure therapy with safety behavior fading and anti-phobic actions, and (4) a wait-list control condition. All participants will complete an online prescreen and face-to-face screening assessment to determine eligibility and pre-treatment symptom severity. Participants will also complete assessments at post-treatment and 1-month follow-up assessments. Subjective fear during two behavioral approach tests (in the treatment and generalization context, respectively) conducted at pre-treatment, post-treatment, and 1-month follow-up assessments will serve as the primary measure of treatment outcome. Additionally, a battery of self-report questionnaires will be completed at pre-treatment, during treatment, at post-treatment, and at a 1-month follow-up assessment.

Inclusion Criteria:

1. Age 18 to 65.
2. Fluent in English (written and spoken). This is required because assessment instruments are validated only in English.
3. Meet DSM-IV criteria for specific phobia, natural environment type, with acrophobic concerns, based on the Composite International Diagnostic Interview (CIDI-Auto; World Health Organization, 1997).
4. Report moderate fear or avoidance (i.e., a score of 30 or higher) on a modified version of the Acrophobia Questionnaire (AQ; Cohen, 1977).
5. Exhibit at least moderate fear (i.e., a fear score of 50 or higher, where 0 = no fear and 100 = extreme fear) during two behavioral approach tests (BATs) consisting of ascending two moderately challenging flights of stairs.

Exclusion Criteria:

1. Medical condition(s) which may prevent safely climbing or descending stairs or walking for more than 15 minutes at a time (It will be necessary to walk to different sites for the behavioral approach tests).

De-identified data can be shared upon request to the corresponding investigator / author upon project completion. Contact Michael J. Telch, Ph.D at telch@austin.utexas.edu