Specific causes for the onset of PTSD following a trauma aren't clearly defined, although experts suspect it may be influenced both by the severity of the event, by the person's personality and genetic make-up, and by whether or not the trauma was expected. First response emergency personnel and individuals directly involved in the event or those children and families who have lost loved ones are more likely to experience PTSD. Natural disasters account for about a 5% rate of PTSD, while there is a 50% rate of PTSD among rape and Holocaust survivors.

Media coverage plays a new role in both adult and pediatric onset of PTSD symptoms. The heightened level of news footage of actual traumatic events, such as the Oklahoma City bombing and the terrorist attack on the World Trade Center and the Pentagon, increases the exposure to the violence, injury, and death associated with the event and may reinforce PTSD symptoms in individuals, especially young children who cannot distinguish between the actual event and the repeated viewing of the event in the media.

PTSD symptoms are distinct and prolonged stress reactions that naturally occur during a highly stressful event. Common symptoms are:

• hyperalertness
• fear and anxiety
• nightmares and flashbacks
• sight, sound, and smell recollection
• avoidance of recall situations
• anger and irritability
• guilt
• depression
• increased substance abuse
• negative world view
• decreased sexual activity

Symptoms usually begin within three months of the trauma, although sometimes PTSD doesn't develop until years after the initial trauma occurred. Once the symptoms begin, they may fade away again within six months. Others suffer with the symptoms for far longer and in some cases, the problem may become chronic.

Among the most troubling symptoms of PTSD are flashbacks, which can be triggered by sounds, smells, feelings, or images. During a flashback, the person relives the traumatic event and may completely lose touch with reality, suffering through the trauma for minutes or hours at a time, believing that the traumatizing event is actually happening all over again.

For a diagnosis of PTSD, symptoms must include at least one of the following so-called “intrusive” symptoms:

• flashbacks
• sleep disorders: nightmares or night terrors
• intense distress when exposed to events that are associated with the trauma

In addition, the person must have at least three of the following “avoidance” symptoms that affect interactions with others:

• trying to avoid thinking or feeling about the trauma
• inability to remember the event
• inability to experience emotion, as well as a loss of interest in former pleasures (psychic numbing or blunting)
• a sense of a shortened future

Finally, there must be evidence of increased arousal, including at least two of the following:

• problems falling asleep
• startle reactions: hyperalertness and strong reactions to unexpected noises
• memory problems
• concentration problems
• moodiness
• violence

In addition to the above symptoms, children with PTSD may experience learning disabilities and memory or attention problems. They may become more dependent, anxious, or even self-abusing.

Recovery may be slowed by injuries, damage to property, loss of employment, or other major problems in the community due to disaster.