Journal Article

Effects of the histone deacetylase inhibitor valproic acid in combination with fear-memory retrieval before exposure therapy for spider phobia: A randomized controlled trial

Schicktanz, Nathalie, Schenker, Maya Thalia, Lang, Undine, Gräff, Johannes, Huber, Carlo Andreas, Zimmer, Anja, Iseli, Galya Clara, Bentz, Dorothée, Howald, Jeanne, Dechent, Frieder, de Quervain, Dominique J. F.

2025

Overview

Return of fear after successful exposure therapy for a phobia is a common clinical challenge. A previous study on mice demonstrated that the persistent attenuation of remote fear memories can be achieved by combining histone deacetylase inhibitors (HDACis) with fear-memory retrieval prior to extinction training. To evaluate the translational potential of this approach, we conducted a randomized, double-blind, placebo-controlled trial. Forty-eight individuals with DSM-IV spider phobia received either HDACi valproic acid (VPA, 500 mg) or a placebo prior to the retrieval of fear memory, followed by exposure therapy in virtual reality. No significant group difference was found in terms of behavioral change on the behavioral approach test at 3 months follow-up and baseline (primary outcome). However, the VPA group displayed significantly reduced fear in two self-report questionnaires related to spider phobia (Fear of Spiders Questionnaire; Spider Phobia Beliefs Questionnaire) as compared to the placebo group. No group differences were observed for psychophysiological indicators of fear. The favorable impact of a single administration of VPA in combination with fear-memory retrieval prior to exposure therapy suggests that it might be an effective way to enhance symptom improvement at the subjective level in the treatment of phobias. Further studies need to investigate the conditions under which an improvement on the psychophysiological and behavioral levels can be achieved as well.

• Publisher: Cambridge University Press
• Subject: Acids / Adult / Animals / Anxiety disorders / Behavior change / Clinical trials / Combined Modality Therapy / Computer applications / Double-Blind Method / Exposure therapy / Extinction / Fear / Fear & phobias / Fear - drug effects / Fear - psychology / Female / Groups / Histone deacetylase / Histone Deacetylase Inhibitors - administration & dosage / Histone Deacetylase Inhibitors - pharmacology / Humans / Implosive Therapy - methods / Male / Medical treatment / Memories / Memory / Mental Recall - drug effects / Middle Aged / Neuroplasticity / Original Article / Phobic Disorders - drug therapy / Phobic Disorders - therapy / Physiological psychology / Placebo effect / Placebos / Questionnaires / Retrieval / Self report / Spider phobia / Spiders / Subjectivity / Therapy / Valproic acid / Valproic Acid - administration & dosage / Valproic Acid - pharmacology / Virtual reality / Young Adult