Background: Reward system dysfunction may play a role in the comorbidity of metabolic syndrome (MetS) in posttraumatic stress disorder (PTSD). Psychological resilience, through its effects on the reward system, may modulate outcomes in PTSD. Utilising a monetary incentive delay task during functional magnetic resonance imaging in a case-control study (PTSD, n = 88, trauma-exposed controls [TEC], n = 85), we aimed to investigate reward system function in relation to PTSD, MetS, and psychological resilience.
Methods: Using repeated measures analysis of variance, we assessed change in activation in the ventral striatum (VS) during reward anticipation and in the orbitofrontal cortex (OFC) during reward outcome, in relation to PTSD, MetS, and psychological resilience, controlling for possible confounders including depression severity, childhood trauma and trauma load.
Results: Activation in the VS and OFC didn't differ in relation to PTSD and MetS. When we controlled for depression severity, PTSD cases had significantly lower activation in the VS and a greater increase in activation in the OFC compared to TEC. Psychological resilience was significantly associated with decreased change in activation in the VS and increased change in activation in the OFC. We also observed a greater increase in activation during reward outcome in the OFC in those with greater childhood trauma exposure and those with exposure to fewer lifetime traumatic events.
Conclusions: The effects of depression and psychological resilience on reward system function in PTSD can be utilised towards developing interventions targeted at altering positive valence systems in PTSD.
Keywords: Childhood trauma; Depression; Functional magnetic resonance imaging (fMRI); Monetary incentive delay (MID) task; Orbitofrontal cortex (OFC); Posttraumatic stress disorder (PTSD); Ventral striatum (VS).
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