PTSD Symptoms Moderate Predictors of Psychophysiological Arousal during Fear Inhibition: Evidence from a Fear, Reward, and Neutral Discrimination Task

Abstract

The ability to distinguish between threatening, rewarding, and neutral cues is adaptative and crucial for survival. However, individuals with posttraumatic stress disorder (PTSD) often show poor knowledge of cue contingencies and heightened fear responses even in the presence of cues that signify safety, potentially due to atypical perceptions of neutral cues. We investigated whether perceiving neutral cues as more rewarding or threatening influences conditioned inhibition of fear and whether PTSD symptoms moderate this relationship. Trauma-exposed adults (N = 84; 64 % female; 76 % non-Hispanic white) completed a Fear, Reward, and Neutral Discrimination (FRND) Task involving geometric shapes paired with outcomes (Fear: white noise; Reward: monetary gain; Neutral: no outcome) and conditioned inhibition trials (Fear+Neutral and Reward+Neutral: no outcome). Skin conductance responses (SCR) quantified psychophysiological arousal, and participants rated the valence of each cue. PTSD symptoms were evaluated with the PTSD Checklist for DSM-5. Linear regressions examined PTSD severity as a moderator of the relationship between Reward vs. Neutral or Fear vs. Neutral valence difference and SCR during inhibition. Among individuals with less severe PTSD symptoms, stronger fear inhibition effects were observed when neutral cues were rated more similarly to reward cues (β = 0.12, p = .022); however, this relationship was not significant at average or higher PTSD severity. Our results emphasize that perceptions of neutral cues contribute to fear inhibition and may underlie PTSD-related deficits in safety learning. Future investigations on PTSD and fear inhibition should consider incorporating measures of reward-related processing to examine the overlap between rewarding and inhibitory qualities of safety signals.