A systematic review of spontaneous recovery in human fear conditioning.

Spontaneous recovery is regarded as an experimental analogue of relapse following successful treatment of anxiety and traumatic disorders using exposure therapy. This systematic review examines the evidence for spontaneous recovery within human fear conditioning, highlighting its broad application in research and implications of findings for potential clinical implications. PubMed, Medline, and PsycINFO were searched from inception to 09/04/2026. In total, the search yielded 4,655 articles, of which 242 were included in the review. A meta-analysis was not conducted and the review was not preregistered. Evidence suggests differences in spontaneous recovery exist between clinical populations and healthy control groups, particularly for posttraumatic stress disorder, with mixed evidence observed in anxious versus healthy individuals. Our review reveals that paradigms involving a ~ 24-h delay between extinction and spontaneous recovery test (typically conducted across two consecutive days) are most frequently used and might produce the strongest effects. Importantly, we identify converging patterns between experimental findings and clinical outcomes between spontaneous recovery and the real-world efficacy of pharmacological interventions, providing preliminary support for the translational relevance of the paradigm. However, we note the slow uptake of non-pharmacological interventions in clinical trials despite promising experimental data and discuss findings from neurotransmitter and sleep studies that offer insights for optimizing exposure therapy. These findings suggest future research directions, including evaluating the correlation between experimental and clinical outcomes, exploring optimal conditions for the observation of spontaneous recovery, and understanding the effects of brain stimulation on fear conditioning.