New data show ketamine (a drug widely used for anaesthesia and pain relief) has a rapid antidepressant effect in some patients with severe depression. The first UK study of ketamine intravenous infusions in people with treatment-resistant depression was conducted by the Oxford Health NHS Foundation Trust and the University of Oxford.
Principal investigator Dr Rupert McShane explained, "Ketamine is a promising new antidepressant which works in a different way to existing antidepressants. We wanted to see whether it would be safe if given repeatedly, and whether it would be practical in an NHS setting. "
The 3-week study was carried out in 28 patients with severe depression that had persisted despite multiple antidepressant and talking therapies. After treatment with ketamine (either 3 or 6 infusions), depression scores had halved in 29% of patients. The median duration of benefit was 2.3 months with 15% of patients being relapse-free for over 2 months. The team have now given ketamine to 45 patients with a 20% success rate.
Dr McShane commented "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... For some, even a brief experience of response helps them to realise that they can get better and this gives hope."
Ketamine is also used as a recreational drug or drug of abuse and in this setting is associated with severe bladder problems and cognitive impairment. However, the dose used in this study was significantly lower than that used on the street and did not cause cognitive or bladder problems after up to six infusions.
Most patients experienced some kind of distortion of their perceptions whilst ketamine was being infused, but these effects were short-lived and not connected to the antidepressant effect. Patients did not feel euphoric during treatment.
Dr McShane concluded, "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... By trying different infusion regimes and adding other licensed drugs, we hope to find simple ways to prolong its dramatic effect.'