A hallucinogenic chemical found in 'magic mushrooms' could one day be used as a treatment for depression, new research has suggested.
A small pilot study of 12 patients with treatment-resistant depression found that every patient experienced a some decrease in symptoms a week after taking the strictly controlled Class A drug - psilocybin.
Seven patients continued to show an improvement and five remained symptom-free three months after the trial.
The treatment involved a high dose of psilocybin, equivalent to eating several magic mushrooms.
All the patients had to "trip" on the drug, just as if they were taking it recreationally to experience its hallucinogenic effects.
Taking psilocybin can result in "mystical or spiritual-type experiences", lead scientist Dr Robin Carhart-Harris, from Imperial College London said.
He said that all patients received psychological support to help them cope and volunteers were carefully screened to exclude anyone with a history of suicide attempts, psychosis or drug dependence.
The treatment produced few serious side effects - although all patients did experience some anxiety.
Dr Carhart-Harris said the results were "encouraging" and larger trials were now needed.