Symbolic online exposure for spider fear: Habituation of fear, disgust and physiological arousal and predictors of symptom improvement

Abstract

Background and objectives This research compared the effects of real versus hyper-real images on anxiety, disgust, and physiological arousal during internet-delivered exposure in high spider-fearfuls. Hyper-real images were digitally altered to highlight fearful aspects. A further aim was to examine self-reported and behavioural therapeutic outcomes and exposure-related predictors of these outcomes. Methods Twenty-eight females were randomised to real (n = 14) or hyper-real (n = 14) treatment groups and nine participants were subsequently allocated to a wait-list control group. Treatment groups viewed an 8-stage exposure hierarchy of real or hyper-real spider images. Subjective anxiety and disgust ratings were taken during each stage (0, 60, 120, 180 s) with heart rate and skin conductance recorded throughout. Results Anxiety, disgust and physiological arousal habituated within each exposure stage, with no differential effect of real compared to hyper-real images. Both treatment groups but not controls demonstrated significant reductions in behavioural avoidance and self-reported phobic symptoms from pre-treatment to post-treatment with large effect sizes noted. The change in within-stage habituation of anxiety, disgust and heart rate, between the first and last stage, predicted improvement in behavioural avoidance at post-treatment. This suggests that generalisation of habituation to multiple images is an important predictor of improvement. Limitations While findings in relation to therapeutic outcome should be considered preliminary, clear relationships were found between exposure-related variables and outcome among those who undertook treatment. Conclusions Findings provide evidence in support of the efficacy of online image-based exposure and have implications for informing further research into the underlying mechanisms of image-based exposure treatment.