A Systematic Review of Fear Learning, Extinction Learning, and Reversal Learning in Obsessive-Compulsive Disorder

Objective: Given the implications in the etiology and treatment of obsessive-compulsive disorder (OCD), this systematic review examined fear acquisition, extinction learning, and reversal learning processes in individuals with OCD.Data Sources: In accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, PubMed (1946-October 26, 2021), PsycInfo, and Embase were searched for empirical studies utilizing classical or reversal learning paradigms to compare learning and extinction processes in individuals with and without OCD.Study Selection: A total of 15,603 articles (7,761 from PubMed, 1,128 from PsycInfo, 6,711 from Embase, 3 from citation review) were identified. Articles were screened for duplicates and inclusion/exclusion criteria. Eleven studies met all inclusion/exclusion criteria.Results: Across studies, minimal evidence of abnormal fear learning was found. However, developmental differences emerged for extinction learning. Youth with OCD displayed impaired extinction learning and safety signal discrimination. Meanwhile, adults largely showed deficits in extinction recall. Conflicting findings emerged regarding impairments in reversal learning. Across learning processes, neuroimaging data implicated the importance of the ventromedial prefrontal cortex (vmPFC).Conclusions: The physiological and neuroimaging data suggest that extinction learning impairment varies across development. Notably, key associative learning processes remain largely unexamined. Findings underlying abnormalities in extinction learning suggest the potential of novel therapeutic approaches, such as neuromodulation and psychotherapy augmentation strategies (ie, attention bias modification training), to precisely target and resolve identified deficits.