Ketamine 'has anti-depressant effect'
3 April 2014 Last updated at 07:44 BST
NHS researchers say the illegal drug ketamine could be a "dramatic" and "exciting" new treatment for depression.
The drug has recently become widely used by young people at parties and has been blamed for killing one young woman.
Dr Rupert McShane, one of the authors of the report, said trials had shown ketamine has "a rapid anti-depressant effect in people who have got otherwise treatment-resistant depression".
He added: "There's a long way to go, and I certainly don't think it's going to be routinely available until we find a better way of maintaining the effect in a more reliable way."
First broadcast on the Today programme on Thursday 3 April.