Ketamine may help treat severe depression

The party drug ketamine may be a "promising and dramatic" new treatment for severe depression, a new Oxford study has claimed.

Researchers who conducted the first trial in the UK confirmed that ketamine has a rapid antidepressant effect in some patients with severe depression who have not responded to other treatments.

These are patients suffering from severe depression which may have lasted years despite multiple antidepressants and talking therapies.

Although many patients relapsed within a day or two, 29 per cent had benefits which lasted at least three weeks and 15 per cent took over two months to relapse.

"Ketamine is a promising new antidepressant which works in a different way to existing antidepressants," said principal investigator Dr Rupert McShane from the Oxford University.
 

Ketamine did not cause cognitive or bladder side effects when given on up to six occasions, although some people did experience other side effects such as anxiety during the infusion or being sick, researchers said.

The team gave over 400 infusions to 45 patients and are exploring ways to maintain the effect.

"We've seen remarkable changes in people who've had severe depression for many years that no other treatment has touched.

"It's very moving to witness. Patients often comment that that the flow of their thinking seems suddenly freer. For some, even a brief experience of response helps them to realise that they can get better and this gives hope," McShane said.

In treatment-resistant depression, electroconvulsive therapy (ECT) is sometimes considered.

In the Oxford study, 28 patients with treatment-resistant depression were treated over three weeks.

They received either three or six ketamine infusions lasting 40 minutes.

Memory tests were carried out a few days after the final infusion. Patients reported their mood symptoms daily via text or email.

The antidepressant response sometimes took a second ketamine infusion to become apparent. Three days after the last infusion, the depression scores had halved in 29 per cent of the patients.

In those that responded to the treatment, the duration of benefit varied widely, lasting between 25 days and eight months.

"Intravenous ketamine is an inexpensive drug which has a dramatic, but often short-term, effect in some patients whose lives are blighted by chronic severe depression," said McShane.

Some patients became anxious during the infusions and some did not complete the course because they did not feel they were benefiting, researchers said.

The findings were published in the Journal of Psychopharmacology.