Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by very stressful, frightening or distressing events.
PTSD can develop immediately after someone experiences a disturbing event or it can occur weeks, months or even years later.
PTSD is estimated to affect about 1 in every 3 people who have a traumatic experience, but it’s not clear exactly why some people develop the condition and others don’t.
Read more about the causes of PTSD.
Someone with PTSD will often relive the traumatic event through nightmares and flashbacks, and may experience feelings of isolation, irritability and guilt.
They may also have problems sleeping, such as insomnia, and find concentrating difficult.
These symptoms are often severe and persistent enough to have a significant impact on the person’s day-to-day life.