Most people with OCD see their obsessions as irrational. People who are severely depressed and who are brooding obsessively usually do not. Problems in upbringing, traumatic early experiences, biochemical abnormalities, and even infectious agents have all been suggested as possible causes. The symptoms of PTSD can range from constantly reliving the event to a general emotional numbing. Persistent, low-level anxiety, attacks of intense anxiety or panic, nightmares, and insomnia are common.
Some people become aggressive, even violent.
Because any reminder of the trauma generally provokes intense distress, people with PTSD typically avoid situations similar in any way to the traumatic event. For example, a rape victim with PTSD might avoid all contact with men. Someone who had survived a plane crash might refuse to ride in any moving vehicle. Someone who had seen young children die or be maimed during a war might become intensely anguished whenever in the presence of children who are the same age as those who died. Although PTSD clearly has an immediate environmental cause, experts are studying the differences between people who do and do not develop PTSD after a remarkable trauma.