The association between fear extinction, the ability to accomplish exposure and exposure therapy outcome in specific phobia

Great interest exists in maximizing exposure therapy efficacy in anxiety disorders. At the same time, reduced frequency and shortened duration of exposure sessions are required to meet the specific regularities in routine care settings. Extinction has emerged as the key mechanism of exposure treatment in anxiety disorders. Examining exposure treatment processes from the perspective of extinction learning might provide novel insights into variability in exposure treatment duration and outcome. The present study sought to examine the functional link between fear extinction, the ability to accomplish exposure in a predetermined time and exposure therapy outcome in specific phobia. Treatment-seeking individuals (N = 53) with spider phobia underwent a context-dependent fear conditioning paradigm prior to a standardized exposure. Spider-phobic participants who were able to complete exposure within the pre-determined time (i.e., completers) showed a more pronounced short- and long-term exposure therapy benefit. In the fear conditioning task, a more pronounced decline in CS-US contingency ratings during extinction (retrieval) was found in completers relative to non-completers. The failure to further extinguish US expectancy to the CSs in non-completers might offer a potential mechanistic explanation why non-completers have difficulties to accomplish all exposure steps in a fixed time and show less pronounced treatment gains. Our findings bear specific implications for the implementation of exposure treatment to routine care settings.