Objective To assess the effectiveness of a novel imaginal intervention for people with acrophobia. Methods The design was a randomized controlled trial with concealed randomization and blinded to other participants' intervention. The intervention was a single novel imaginal intervention session or a 15-min meditation. The setting was in Auckland, New Zealand. The participants were a convenience sample of the public with a score >29 on the Heights Interpretation Questionnaire (HIQ), a questionnaire validated against actual height exposure. The primary outcomes were the proportion of participants with a score <26 on the HIQ at eight weeks and difference between the HIQ scores between the two arms of the study. Results Ninety-eight participants (92%) returned their questionnaire and were included in the intention to treat analysis. The HIQ score <26 was 34.6% (18/52) in the intervention group and 15.2% (7/46) in the control group RR = 2.26, 95% CI (1.05, 4.95) and p = 0.028. The numbers needed to treat is six 95% CI (3 to 36). Participants with scores <26 report their fear of heights is very much improved. There was a 4.5-point difference in the HIQ score at eight weeks (p = 0.055) on the multiple regression analysis. Conclusions This is the first randomized trial of this novel imaginal intervention which is probably effective, brief, easily learnt, and safe. It may be worth considering doing this prior to some of the longer or more expensive exposure therapies. This study will be of interest to family doctors, psychiatrists, and psychologists.
Keywords: acrophobia; clinical trial; phobia disorders; primary health care; single-blind method.