Study terminated as a result of the dissolution of the Sponsor.

The purpose of this study is to assess the safety and effectiveness of cortical stimulation to the cerebral cortex of subjects who have suffered from treatment-resistant depression and have failed routine attempts at controlling their depression.

Major depressive disorders are the most common of all psychiatric disorders. The World Health Organization estimates that 340 million people worldwide suffer from an episode of major depression each year, accounting for 4.4% of the overall global disease burden. In the United States, about 9.5% or 19 million people are affected by a depressive disorder, with a lifetime risk of about 17% for a major depressive disorder.

While depression can be effectively treated in the majority of patients by medication and psychotherapy, up to 20% of patients fail to respond. Electroconvulsive Therapy (ECT) is effective in approximately 70% of cases where antidepressant medications do not provide sufficient relief of symptoms. However, as many as 20-50% of the people who respond well to a course of ECT relapse within 6 months, therefore, periodic maintenance therapy is often required.

For those patients who are resistant to the therapies noted above, more invasive approaches have been used, including Vagus Nerve Stimulation (VNS) and more recently Deep Brain Stimulation (DBS).

Direct cortical stimulation of the cortex via an implanted device system may provide long lasting benefit with minimal side effects. The current study seeks to assess in a feasibility study the safety and efficacy of stimulating the prefrontal cortex in patients with major depressive disorder.

Inclusion Criteria:

• Current major depressive episode (MDE) lasting for at least two years, or at least 4 lifetime MDEs with the current episode lasting for at least one year
• Severe depression at study entry defined as a minimum score of 20 on the Hamilton Depression Rating Scale
• Failed response to at least four different antidepressant treatments

Exclusion Criteria:

• Axis I psychiatric diagnoses including schizophrenia, bipolar disorder, panic disorder, obsessive compulsive disorder, or evidence of global cognitive impairment
• An Axis II diagnoses of either: a) borderline personality disorder, or b) histrionic personality disorder
• Electroconvulsive therapy within 6 months prior to enrollment
• Known need of electroconvulsive therapy while the investigational device is implanted
• History of seizure disorder or status epilepticus