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Experiencing traumatic events has a high lifetime prevalence ranging between 60.7 and 76.2% across different countries (1). Exposure to traumatic events is associated with a higher risk for various mental disorders such as posttraumatic stress disorder (2, 3), which are related to high individual and societal costs (4). The development of interventions to prevent adverse mental health consequences following traumatic event exposure is therefore of vital importance. This, however, requires detailed knowledge about the underlying biological and psychological mechanisms involved in the association between traumatic events and psychopathology. Various risk factors at different levels have already been described in the last decades (5). Biological risk factors include genetic and epigenetic variations (6), alterations in the function of the hypothalamic pituitary adrenal (HPA) axis (7, 8) and the autonomic nervous system (9) as well as changes in brain structure and functioning (10). Psychological risk factors include impairments in cognitive abilities (11) and specific personality traits such as high trait anxiety (12) and maladaptive emotion regulation (13). Social risk factors include impaired interpersonal relations and stigmatization (14, 15). Further, clinical risk factors such as mental health history as well as previous traumatic experiences may also increase the risk for psychopathology after trauma exposure (16). Most of these factors are supposed to be associated with risk of psychopathology independent of the type of traumatic event. However, it is likely that specific traumatic events are associated with different constellations of risk factors, which has so far received little attention in the existing literature. Importantly, traumatic events explicitly include not only events that are personally experienced but also events that are witnessed by an observer (17). This includes witnessing someone being seriously hurt, seeing atrocities or witnessing dead bodies. Witnessed traumatic events are among the most frequent traumatic experiences (1). They are also of high current relevance in the contexts of natural disasters, terrorist attacks and military crises (16, 18, 19). The fact that individuals can develop psychopathological reactions to events that are actually experienced by others raises the question how the suffering of others is being processed. Based on theoretical models and findings from social cognition and neuroscience research, we propose that socio-affective and socio-cognitive mechanisms are involved in the processing and pathological consequences of witnessing traumatic events and could contribute to a better understanding of adverse reactions to this type of traumatic events.