Post-traumatic stress disorder (PTSD) usually occurs as a result of an individual experiencing a severely distressing, traumatic or catastrophic event. PTSD can affect people of any age and around one third of those who face such an event go on to develop PTSD.

It is common to develop distressing or confused feelings after a traumatic event. The feelings may not develop immediately, with a person remaining emotionally numb to the event at first. Eventually, physical and emotional reactions may start to develop such as being unable to sleep or being upset easily. For many people, these emotions start to fade within a fairly short period of time, but if the emotions are very extreme or last for more than a month, the affected individual may be diagnosed with PTSD.

Other terms that have been used to describe PTSD in the past include soldier’s heart, combat stress, battle fatigue and shell shock. Some examples of the type of events that can lead to PTSD include suffering or witnessing an accident, terrorist attack, flood or other natural disaster; being attacked, assaulted, robbed, raped or mugged; witnessing violence; being sexually or physically abused or experiencing the battlefield and seeing death and active killing. PTSD does not refer to the stress that people suffer in response to events such as a house move, a divorce, bankruptcy, job change or failed interview.

Experts are unclear about why some people develop PTSD and others do not, but as with most mental health issues, it is likely to be due to a combination of factors. Some of these are described below.

• Inherited risk factors such as a susceptibility to anxiety and stress
• Traumatic events experienced during childhood
• Abnormal regulation of the hormones related to stress
• Having experienced long-lasting trauma
• A job that involves exposure to traumatic events such as the military or a career in paramedics
• Family history of PTSD or other mental health issues
• Lack of friends and family

PTSD can only be effectively treated if it is recognized and diagnosed. Following events such as a natural disaster, the screening of individuals who may be at risk of PTSD is sometimes arranged. Opportunities to screen for and diagnose PTSD are also usually available following events such as sexual assault or murder. Diagnosing PTSD in children can be particularly problematic, but asking children directly about their experiences can improve the chances of correctly identifying and diagnosing the problem.