Post-traumatic stress disorder (PTSD) develops after experiencing or witnessing a deeply distressing event. While trauma affects people differently, certain types of experiences are more strongly associated with PTSD. Here are five common causes that many individuals report as the origins of their symptoms.

One major cause is exposure to violence, such as assault, robbery, domestic violence, or community violence. When a person is harmed or threatened, the brain can stay on high alert long after the danger has passed, leading to intrusive memories, hypervigilance, and fear responses. Physical or sexual assault is among the most frequently reported causes of PTSD in both adults and adolescents.

Another common cause is combat or military-related trauma. Soldiers and veterans often experience life-threatening situations, witness deaths, or endure prolonged periods of fear and uncertainty. These intense stressors can overwhelm the nervous system and trigger long-term psychological reactions.

Serious accidents, such as car crashes, industrial injuries, or natural disasters, are also significant contributors. These events happen suddenly and can leave survivors feeling powerless and vulnerable, which can later manifest as flashbacks, anxiety, and avoidance behaviors.

Childhood trauma, including physical abuse, neglect, or witnessing violence in the home, is a fourth major cause. Because children are still developing emotionally and neurologically, traumatic experiences at a young age can shape how they process danger, trust, and relationships throughout life.

Finally, medical emergencies or life-threatening health events such as intensive care unit stays, complicated childbirth, severe illness, or sudden surgeries can also lead to PTSD. These experiences often involve fear, pain, and a sense of losing control, which can linger long after recovery.

While these are five common causes, any deeply distressing event can lead to PTSD. What matters most is the individual’s emotional response, not the type of trauma itself.