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Doctoral Dissertation Announcement
Candidate: Richard William Seim
Doctor of Philosophy
Title: Dosed versus Prolonged Exposures: A Direct Comparison of One-Session Treatments for Animal Phobias
Dr. C. Richard Spates, Chair
Dr. Ellen I. Koch
Dr. Scott T. Gaynor
Dr. Amy E. Naugle
Date: Wednesday, June 22, 2011 10:00 a.m. to Noon
1509 Wood Hall
It is widely accepted that, for exposure-based therapies to be effective, fear-eliciting stimuli must be presented continuously until there is a marked decrease in the client’s anxiety (e.g., Eysenck, 1979; Foa & Kozak, 1986). However, an emerging body of research (cf. Seim, Waller, & Spates, 2010) suggests that a massed series of very brief exposures (< 150 sec) may be effective in the extinction of fear responses. The present study was designed to compare the efficacy and acceptability of two one-session treatments for animal phobias: one that utilized continuous, uninterrupted periods of exposure to a feared animal (Prolonged Exposures) and the other that utilized a massed series of brief (5-120 sec) exposure trials (Dosed Exposures). Twenty-four adults (7 males, 17 females) between the ages of 18 and 57 years (M = 23.6) participated in this study. Each individual met DSM-IV criteria for a diagnosis of snake phobia or spider phobia. Participants were randomly assigned to one of two interventions. Both treatments required participants to gradually enter a room, approach, and eventually hold a live ball python or tarantula. Results from mixed model (between × within subjects) analyses of variance showed that the Dosed Exposure treatment performed equally well to Prolonged Exposures at decreasing behavioral avoidance, feelings of anxiety, perceptions of threat, and phobia-specific cognitions from pre-treatment to post-treatment, and these gains were maintained at one-week follow-up. Although participants receiving Prolonged Exposures reported lower ratings of within-session anxiety, participants in the Dosed Exposure group had lower rates of treatment dropout, better compliance with procedures, and fewer safety-seeking behaviors during the treatment. These findings suggest that, contrary to popular belief, brief exposure trials can be effective in the extinction of phobic responses under certain conditions.