Gaze-Contingent Music Reward Treatment for PTSD

GC-MRT is designed to shift participants' attention away from threat and toward neutral stimuli by introducing a contingency between viewing patterns and music pre-chosen by participants. Participants view matrices of faces with neutral and angry expressions. Viewing the neutral faces triggers music the participant previously requested, and viewing the angry faces turns the music off. The researchers will compare this condition (GC- MRT) to two additional conditions. In the "exposure" condition (GC-MRT-exp) the investigators will reverse the music contingency such that viewing the angry faces triggers the music while viewing the neutral faces turns the music off. In the placebo control (PC) condition, music plays continuously. The goal of this study is to: (1) examine the efficacy of GC-MRT in PTSD; and (2) elucidate its underpinnings (i.e. attention control, reward processes, and exposure via counter-conditioning). Attention control is the ability to shift attention deliberately based on goal-directed behavior. Accordingly, deficits in attention control can result in volatile shifts in attention leading to increase attention allocation to threat in the environment. Reward functioning is the ability to seek out and enjoy stimuli of positive motivational valence, and is considered a crucial driving force of behavior, guiding the organism towards positive and rewarding experiences, ranging from food and gender to money, music, and positive social interactions. Allocating visual attention to rewarding stimuli is considered a reward-related attentional feature. Counter-conditioning is an alternative to exposure therapy involving pairing of the feared stimulus with an appetitive/positive outcome (i.e., increasing the rewarding/positive value of the feared stimulus), in which repeated trials are supposed to reduce the fear response, and replace it by an appetitive response. Indeed, studies have shown counter-conditioning to be more effective at reducing fear than traditional exposure therapy. The investigators hypothesize that: 1. GC-MRT will produce greater reductions in symptoms compared to PC at post-treatment and follow-up (diverting attention away from threat). 2. GC-MRT-exp will produce greater reductions in symptoms compared to PC at post-treatment follow-up (exposure via counter-conditioning by rewarding threat stimuli). 3. Exploratory analysis will compare the reductions in symptoms of GC-MRT compared to GC-MRT-exp at post-treatment follow-up. Subject population: Seventy-five subjects with PTSD will participate in this study. Methods: The sample (N = 75) will be randomized equally into three groups. Group 1 will receive a 4-week (8 sessions) course of GC-MRT where music will play only when viewing neutral faces, Group 2 will receive a 4-week (8 sessions) course of GC-MRT-exp where music will play only when viewing angry faces, and Group 3 will receive a 4-week (8-sessions) course of non-GC-MRT (i.e. placebo control; PC) where music will play throughout the trials. \*The pictures of the faces used in the intervention will include 50% male and 50% female. Race-wise they are homogenous. Varying the different faces by race is not feasible as these faces were chosen from an established picture data-base (i.e., the Karolinska Directed Emotional Faces database; KDEF) based on the affective ratings of each face. Importantly, this composition of faces is similar to one used in an attention assessment task for which our pilot data shows significant group differences in dwell time, which is the attentional target of the intervention. Hence, we do not expect this to affect the results.