Long-term affective and non-affective brain alterations across three generations following the genocide in Cambodia

Abstract

Importance. The literature has largely indicated that trauma can lead to post-traumatic stress disorder (PTSD) and alterations in brain functioning. However, even though research has shown that descendants of parents who have experienced trauma are more prone to developing PTSD symptoms, it remains unclear whether brain alterations are also observable in subsequent generations. Objective. Uniquely, the present project focused on survivors of the Cambodian genocide and their descendants spanning two generations, to determine whether brain alterations are observable about five decades after the traumatic event and in subsequent generations. Design, Setting, and Participants. We conducted a cross-sectional study with a total of 163 participants (Generation 0=59; G1=52 and G2=52). Using portable electroencephalography (EEG), we used four experimental tasks—two targeting non-affective processing (i.e., sensory gating, oddball) and two targeting affective processing (i.e., emotion recognition, threat processing). Post-traumatic stress disorder was assessed using PTSD Checklist (PCL)-5. All tasks were pre-registered before data acquisition. Results. Using both the frequentist and the Bayesian statistical approaches, we found that, although the rate of PTSD symptoms was similar across generations, the affective reaction to threat was primarily observed, or intensified, in the directly affected generation with PTSD. For other tasks, the persistence of affective and non-affective alterations was not statistically reliable.Conclusions and Relevance. The present study underscores that affective and non-affective alterations might be reduced decades after a trauma, but a sensibility to threat remains in individuals with PTSD. Our results also support a dissociation between PTSD and neural alterations.