(PS2-98) Worse Shifting Ability contributes to the Effect of PTSD Symptom Severity on Functional Impairment

Abstract Text: Posttraumatic stress disorder (PTSD) has a detrimental impact on functioning (i.e., tasks of daily living, mobility, self-care, home life, relationships, community life) that often persists even after symptoms have resolved. Cognitive theory suggests that deficits in executive control, a set of cognitive processes that contribute to goal-directed behavior (i.e., inhibition, shifting, working memory), may be a key contributor to functional disability in PTSD. Specifically, poor inhibition (i.e., the ability to suppress automatic responses) prevents the suppression of maladaptive responses (e.g., avoidance, rumination, threat monitoring) and poor shifting ability prevents disengagement from trauma-related stimuli (e.g., memories, external cues), both of which impair goal-directed processing. Given the considerable impact of PTSD on functioning, even after a successful course of treatment, additional investigation is warranted to identify factors that contribute to this effect. We examined the interactive effect of PTSD symptoms and executive control on functioning in a trauma-exposed community sample (N = 89). Participants completed a baseline assessment with objective measures of inhibition and shifting, a clinical interview from which social and occupational functioning scores were derived, and a self-report measure of PTSD symptoms. PTSD symptoms were positively associated with social and occupational impairment (r = .70, p < .001 and r = .54, p < .001, respectively). Regarding executive control, only shifting ability was associated with social functioning (r = -.33 p = .002), such that as shifting ability decreased, social functioning worsened. As such, shifting was explored as a potential moderator of the association between PTSD symptoms and functional impairment. The interactive effect of PTSD symptoms and shifting was not associated with social functioning (ΔR2 = .005, p = .334). There was a significant interaction for occupational functioning (ΔR2 = .04, β = .21, p = .025), such that the association between PTSD and occupational functioning was stronger among those with worse (β = .83, p <.001), versus better (β = .37, p =.004), shifting ability. Study findings, combined with a growing literature, suggest that deficits in executive control are associated with functional disability in PTSD, yet frontline interventions do not directly target cognitive processes. In future research, replicating this effect using more comprehensive assessments of executive control and functional impairment in clinical samples is warranted. As advances are made in this area of research, computerized cognitive training interventions could prove to be an innovative addition to care for PTSD – one that targets cognitive factors otherwise unaddressed and increases access for groups that might not otherwise receive care.