Executive functioning in posttraumatic stress disorder: Understanding how inhibition, switching, and test modality affect reaction times.

Objective: Posttraumatic stress disorder (PTSD) has been linked to deficits in executive functioning, but the literature suggests these associations are inconsistent. Results vary depending on the task used, test modality, and the specific subdomain being measured, such as inhibitory control (interference resolution, response inhibition) or set shifting (task switching, rule switching). Notably, deficits are more consistently observed in computerized tasks that measure precise reaction times (RTs) than in classic paper-and-pencil measures, but few studies have parsed specific executive functioning deficits in PTSD using detailed analyses of RT data.

Method: The present study used a cued-switching Stroop Task to examine both interference resolution and task switching in 28 veterans with PTSD and 28 age-matched controls. Each trial required attending to a randomly presented cue and responding to the specified target while ignoring irrelevant or opposing information. Analyses of RT distributions estimated both Gaussian (normal) and ex-Gaussian (exponential) parameters.

Results: Veterans with PTSD had slower and more variable RTs than the controls on trials that required ignoring conflicting information (interference resolution, d' = .68). These effects were confined to the normal distribution, not to excessively slow responses (as estimated by ex-Gaussian parameters). Veterans with PTSD also showed modestly slower RTs on trials that required switching between cues, but Bayesian evidence for this was weak, and measures by ex-Gaussian parameters were not significant.

Conclusions: These results highlight the importance of examining executive functioning in PTSD with a more nuanced approach, as clarity around these deficits may have important implications for future intervention and rehabilitation strategies. (PsycInfo Database Record (c) 2024 APA, all rights reserved).