Exposure plus response prevention versus exposure plus safety behaviours in reducing feelings of contamination, fear, danger and disgust. An extended replication of Rachman, Shafran, Radomsky & Zysk (2011)

Background and objectives: Safety behaviours are widely held to impede the beneficial effects of exposure, certainly in OCD. Recently, Rachman, Radomsky, Shafran, and Zysk (2011) challenged this view. Healthy volunteers repeatedly touched a contaminant in two sessions. Half of the participants did not engage in safety behaviours after touching (exposure + response prevention), while the other half did (exposure + safety behaviours, i.e., cleaning hands with a hygienic wipe). Scores of contamination, fear, danger, and disgust decreased in both sessions and the effects were not impeded by safety behaviours. Three potential artefacts were identified in the Rachman et al. study: a no-treatment control group was lacking, the stop rules for ending exposure differed between conditions, and positive expectations may have been induced in the safety behaviours group. We tried to critically replicate the main findings. Method: The Rachman et al. (2011) study was replicated, with 44 volunteers but stop rules and expectations were similar between treatments, and effects were also assessed in a no-intervention control group. Results: Relative to the control condition, both exposure interventions induced reliable decreases in feelings of contamination, fear, danger, and disgust. The decline followed an exponential curve with the largest gains at the first trials of each session. Limitations: Findings were obtained from a non-clinical sample. Conclusion: The findings attest to the robustness of the Rachman et al. findings, and challenge the notion that safety behaviours should be dismissed categorically in exposure treatments.