Imagery Rescripting and Imaginal Extinction attenuate the Return of Generalized Fear

Standard extinction (SE) is the most widely implemented intervention for reducing conditioned and generalized fear; however, the possibility of fear return still remains. Hence, novel interventions may be used to augment the efficiency of SE. Imagery rescripting (ImRS), based on the premise of unconditioned stimulus (UCS) devaluation, encompasses the devaluation of the cognitive representation of the UCS in a positive direction. Imaginal extinction (IE), based on the principles of UCS expectancy evaluation, involves vivid imagination of the conditioned stimuli during extinction. In the current study, we compared the efficacy of ImRS over IE and SE in attenuating the return of generalized fear. Seventy-two healthy individuals were randomly assigned to ImRS, IE, or SE groups. Day 1 comprised the fear acquisition and generalization phases. On day 2, the intervention and generalization testing phases were conducted. On day 3, 15 days after acquisition, the return of fear due to spontaneous recovery was assessed. Our study is the first known to compare the efficacy of ImRS and IE in attenuating the return of generalized fear response. We found that ImRS effectively attenuated the return of fear response. Further, the CS valence increased in a positive direction on Day 3. However, the rate of extinction was slower, and the generalized fear response was sustained for the IE group. The findings suggest that distinct mechanisms may be involved in ImRS and IE. ImRS may require a higher level of cognition, inducing novelty due to introducing the positive narrative. ImRS resulted in a competition between the two memories during retrieval, following a dynamic ‘higher route’. On the contrary, the fear responses were sustained in the IE group, showing the possibility of a slow and stagnant ‘lower route’. Hence, ImRS may be a more effective intervention for attenuating the return of generalized fear.