A landmark study in the United States has found the drug MDMA or ecstasy – when linked with talk-therapy – can help people suffering from Post Traumatic Stress Disorder.

90 people took part in the clinical trial including combat veterans, victims of mass shootings, and first responders – all with severe PTSD lasting more than 14 years.

Two months after treatment, 67 per cent of the MDMA group no longer qualified for a diagnosis of PTSD, compared with 32 percent of the placebo group.

Kathryn talks with the lead author of the study, Dr Jennifer Mitchell, a neuroscientist at the University of California, San Francisco.