Disgust and fear reactions uniquely affect intrusions and posttraumatic stress symptoms.

Disgust reactions commonly occur during/following trauma and predict posttraumatic stress (PTS) symptoms. Yet, disgust is not mentioned in DSM-5 PTSD criteria. To investigate disgust's clinical significance in PTSD, we measured the relationship between disgust (and fear) reactions to a personal trauma, and problematic intrusion characteristics (e.g., distress) and intrusion symptom severity. We focused on intrusions because they are a transdiagnostic PTSD symptom, though we also measured overall PTS symptoms to replicate prior work. Participants (N = 471) recalled their most traumatic/stressful event from the past six months. They then rated disgust and fear reactions to this event and completed the Posttraumatic Stress Disorder Checklist-5. Participants who had experienced intrusions about their event in the past month (n = 261) rated these intrusions on several characteristics (e.g., distress, vividness). We found stronger traumatic event-related disgust reactions were associated with more problematic intrusion characteristics, higher intrusion symptom severity, and higher overall PTS symptom severity. Notably, disgust reactions uniquely predicted these variables after statistically controlling for fear reactions. We conclude disgust reactions to trauma may be similarly pathological to fear reactions for intrusion and broader PTS symptoms. Therefore, PTSD diagnostic manuals and treatments should recognize disgust as a trauma-relevant emotion.

Mechanisms underlying memory enhancement for disgust over fear.

Disgust is remembered better than fear, despite both emotions being highly negative and arousing. But the mechanisms underlying this effect are not well-understood. Therefore, we compared two proposed mechanisms underlying superior memory for disgust. According to the memory consolidation mechanism, it is harder (but crucial) to remember potentially contaminating vs. threatening stimuli. Hence, disgust elicits additional memory consolidation processes to fear. According to the attention mechanism, it takes longer to establish if disgust (relative to fear) stimuli are dangerous. Hence, people pay more attention to disgust during encoding. Both mechanisms could boost memory for disgust. Ninety-eight participants encoded disgust, fear, and neutral images whilst completing a simple task to measure attention. After 10- or 45-min delay, participants freely recalled the images. We found enhanced memory for disgust relative to fear after 10- and 45-min delay, but this effect was larger after 45-min. Participants paid more attention to disgust than fear images during encoding. However, mixed effect models showed increased attention did not contribute to enhanced memory for disgust. Our results therefore support the memory consolidation mechanism.

Why the COVID-19 pandemic is a traumatic stressor.

The COVID-19 pandemic does not fit into prevailing Post-traumatic Stress Disorder (PTSD) models, or diagnostic criteria, yet emerging research shows traumatic stress symptoms as a result of this ongoing global stressor. Current pathogenic event models focus on past, and largely direct, trauma exposure to certain kinds of life-threatening events. Yet, traumatic stress reactions to future, indirect trauma exposure, and non-Criterion A events exist, suggesting COVID-19 is also a traumatic stressor which could lead to PTSD symptomology. To examine this idea, we asked a sample of online participants (N = 1,040), in five western countries, to indicate the COVID-19 events they had been directly exposed to, events they anticipated would happen in the future, and other forms of indirect exposure such as through media coverage. We then asked participants to complete the Posttraumatic Stress Disorder Checklist-5, adapted to measure pre/peri/post-traumatic reactions in relation to COVID-19. We also measured general emotional reactions (e.g., angry, anxious, helpless), well-being, psychosocial functioning, and depression, anxiety, and stress symptoms. We found participants had PTSD-like symptoms for events that had not happened and when participants had been directly (e.g., contact with virus) or indirectly exposed to COVID-19 (e.g., via media). Moreover, 13.2% of our sample were likely PTSD-positive, despite types of COVID-19 "exposure" (e.g., lockdown) not fitting DSM-5 criteria. The emotional impact of "worst" experienced/anticipated events best predicted PTSD-like symptoms. Taken together, our findings support emerging research that COVID-19 can be understood as a traumatic stressor event capable of eliciting PTSD-like responses and exacerbating other related mental health problems (e.g., anxiety, depression, psychosocial functioning, etc.). Our findings add to existing literature supporting a pathogenic event memory model of traumatic stress.