Latent Inhibition Speeds up but Weakens the Extinction of Conditioned Fear in Humans

Bram Vervliet

doi:10.4172/2161-0487.s7-002

Abstract

Prevention is better than cure, but little is known about effective prevention of anxiety disorders. Individuals vulnerable for trauma-exposure would benefit from effective techniques to prevent the development of post-traumatic stress. One reason for the apparent standstill in this literature may be the exclusive focus on the development of fear, while pre-clinical anxiety treatment research has turned to impaired extinction of fear as the main mechanism underlying abnormal anxiety. Conditioning theories propose latent inhibition as a technique to prevent the development of fears, but the effects on fear extinction have not been examined in detail. I conducted two experiments to evaluate the effects of latent inhibition on extinction in a standard human fear conditioning paradigm, which serves as a model for post-traumatic stress disorder. Skin conductance reactivity and online expectancy ratings revealed slower rates of fear acquisition in the latent inhibition groups, as well as a speeded extinction effect early in extinction. However, extinction of expectancy ratings was less complete in the latent inhibition groups. The beneficial effects of the latent inhibition technique may be in promoting early success of self-exposures or exposure treatment and motivating the patient to continue on the exposure path

Highlights

Post-traumatic stress disorder (PTSD) is a highly debilitating disorder that affects up to 40% of trauma victims [1]
Skin conductance response amplitudes were calculated by subtracting the baseline level from the maximal value during that stimulus presentation (0-8 s after conditioned stimulus (CS) onset)
The present study was set up to investigate the effects of stimulus pre-exposures on the conditioning and extinction of fear responses in humans

Summary

Introduction

Post-traumatic stress disorder (PTSD) is a highly debilitating disorder that affects up to 40% of trauma victims [1]. Stress symptoms in the aftermath of a traumatic event are not abnormal, but can develop into full-blown PTSD when they take a chronic course. There are two windows of opportunity to intervene and prevent the development of PTSD: (1) resilience building before the traumatic experience (primary prevention), and (2) early intervention during the aftermath of the traumatic event (up to a few weeks) with the aim of preventing the transition from acute stress effects into chronic stress (secondary prevention). Primary prevention has received much less attention [4], there are identifiable groups vulnerable for trauma exposure (soldiers, rescue workers etc.) that may benefit from effective resilience building programs. The goal is to prevent the development of stress symptoms all together or to increase beneficial coping in the aftermath of the traumatic event. The main aim of this study was to provide a laboratory test of an approach that combines the two windows of opportunity

Objectives

Results

Conclusion