The approval allows a maximum of 20 sites across the US to enroll up to 125 patients.

The BROADEN study is investigating whether or not stimulating an area of the brain known as Brodmann Area 25 (BA25) with DBS system is a safe and effective method for treating severe depression.

The BROADEN study is a controlled, blinded study which selects the participants who are having treatment-resistant depression and are failed with multiple treatments.

Medical University of South Carolina psychiatry, radiology and neurology professor Mark George said treatments such as medications, psychotherapy and electroconvulsive therapy often fail to work for these difficult-to-treat patients, so they are hopeful this research will provide them with a new approach to treat this condition.

St Jude Medical plans to request approval to expand the study to a total of 231 patients at a later date.