The interaction of genes with environmental factors – especially extreme stress – dramatically increases individual risk for psychopathology. This likely occurs through lasting changes in stress signalling pathways that cause adaptations in physiology to help an individual cope with future stress. These adaptive mechanisms occur in all individuals exposed to similar levels of stress or trauma, yet, only a fraction (~15%) go on to develop post-traumatic stress disorder (PTSD), which persists in only ~30% of cases, or an associated disorder such as anxiety or depression. On the other hand, some individuals who have lived through periods of extreme stress have an astonishing ability to recover. Understanding resilience holds the key for developing treatments and interventions to transform the at-risk into resilient individuals.
Refugees constitute an extremely stressed population. Through exposure to war-related trauma and post-migration stressors, the risk for refugees to develop severe psychiatric problems compared to the general population is increased. Longitudinal studies indicate that post-traumatic stress reactions in refugees may persist and even increase over time. However, there are substantial differences in how individuals respond to extreme stress, so while some refugees develop psychopathology, the majority are resilient. New evidence also indicates that risk or resilience to the effects of extreme stress may be biologically passed on to offspring via specific molecular processes, adding to a sustained impact in these populations. There remain several critical unanswered questions: How does extreme stress lead to psychiatric illness?
How are some individuals resilient? How is this risk/resilience passed to future generations? I will address these questions from a genetic, epigenetic and molecular perspective and discuss ways in which molecular biomarkers can be identified and utilised to ultimately identify individuals at risk and improve their resilience.