Comparing three extinction methods to reduce fear expression and generalization.

Fear extinction is easy to achieve but difficult to maintain, as evidenced by the relapse of fear after extinction. Counterconditioning and novelty-facilitated extinction have been shown to interfere with fear expression without erasing it. Because of the similarity between the two extinction paradigms, we extended the standard extinction, which merely omitted the expected threat outcomes after exposure to original threat cues. The modified paradigm provided a stimulus (neutral picture or positive picture) to replace the omitted threat outcomes during extinction. Sixty-four healthy volunteers were randomized into three groups for a three-day procedure: fear acquisition (day 1), fear extinction (day 2), and fear recall and generalization test (day 3). Our results showed the modified extinction paradigm failed to prevent fear expression in spontaneous recovery and reinstatement tests. However, novelty-facilitated extinction showed powerful effects in preventing fear generalization. Besides, there was a negative correlation between spontaneous recovery index and emotion regulation scores. We speculated that emotion and prediction error may be important factors influencing fear extinction and affect fear recall and generalization. Overall, this study suggests that novelty-facilitated extinction had a superior effect in preventing fear generalization, providing new perspectives for enhancing the effect of exposure therapy.