This week we’ll explore Post Traumatic Stress Disorder - PTSD. What is it? And why is it so controversial?

Many people in the world are exposed to extraordinary, traumatic events- wars, earthquakes, accidents and crime. Most recover in time but, for some, the trauma takes over their lives, leaving them unable to function.

Mike Williams talks to a war veteran and a tsunami survivor, who tell their stories of how they came to be diagnosed with PTSD. But do the public know what this diagnosis really is? Or has it been confused with a broader term for anyone who has suffered a trauma? Is it a useful diagnosis across cultures?(Image of French soldiers in vietnam. Credit:STAFF/AFP/Getty Images)