South Islanders suffering from treatment-resistant depression, are being asked to volunteer for a new ketamine  trial

Otago University researchers are looking into whether Behavioural Activation Therapy can help sustain the effects of ketamine depression treatment, and are seeking 60 participants from Christchurch and Dunedin.

Study investigator Dr Ben Beaglehole says they'll be testing the drug in a liquid form, to lessen the 'trip' effect.

He says they hope in the future, ketamine can be delivered in a much more tolerable way - and understand the importance of psychotherapy.