The war in Ukraine, like other conflicts around the world, will mean millions of people going through horrific and traumatic events. Some may go on to develop post-traumatic stress disorder, or PTSD, experiencing psychological distress for months or even years afterwards. Ian Sample speaks to clinical psychologist Jennifer Wild about what happens in the body and brain when someone gets PTSD, why some people may be more susceptible to developing it than others, and how understanding the underlying psychology can help to build resilience and improve treatments for the future. Help support our independent journalism at theguardian.com/sciencepod