Extinction learning and return of fear in a large sample of children and adolescents with and without anxiety disorders.

Anxiety disorders are the most prevalent mental health problems in childhood and adolescence, highlighting the importance to study their underlying mechanisms. One key process in fear reduction, particularly in exposure-based cognitive behavioral therapy, is extinction learning. While extensively studied in adults, its role in youth remains underexplored. The aim of the present study was to examine fear extinction learning and return of fear in a large sample of children and adolescents (N = 274; age range 8-16 years, M = 11.07, SD = 2.22; 55.8 % female) with separation anxiety disorder, social anxiety disorder, and specific phobia (n = 217) in comparison to non-anxious controls (n = 57). All children participated in a 2-day fear conditioning paradigm. Fear acquisition, extinction, and reinstatement were assessed using subjective (valence, arousal, contingency) and psychophysiological (startle) indicators of emotional reactivity. Successful differential fear acquisition could be observed in both groups. Extinction learning was also successful as the fear response to the CS+ decreased. Contradicting previous findings suggesting impairment in extinction in children with anxiety disorders, we could not find differences in fear extinction learning between anxious and non-anxious children and adolescents; both groups learned to inhibit their fear response when the CS+ no longer predicted the occurrence of the aversive outcome. Further research is needed to disentangle the role of fear extinction learning within childhood anxiety disorders and determine whether children with anxiety disorders generally do not show deficits in extinction learning or whether this deficit is limited to disorder specific stimuli.