The drug ketamine may have moved a step closer to routine use as an antidepressant. Positive – if modest – results from a large trial of an intranasal spray based on ketamine were announced by pharmaceutical giant Janssen today.

The firm is developing the treatment for people with severe depression who aren’t helped by existing medication or who are suicidal . If everything goes to plan, the medicine could be available next year in the US and Europe.

Ketamine has long been used as an anaesthetic in people and animals. …