European Deep Brain Stimulation (DBS) Depression Study

Inclusion Criteria:

• Men and women (non-pregnant) age is 21-70 years;

• Diagnosed with non-psychotic major depressive disorder, single or recurrent episodeby Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition, TextRevision, 2000 (DSM-IV-TR) criteria derived from the Mini InternationalNeuropsychiatric Interview (MINI);

• First episode onset before age 45;

• Current episode > 12 month duration;

• In the current episode: Documented resistance to a minimum of 4 adequate depressiontreatments from at least 3 different categories;

• In adult lifetime (>21 year of age) have experience a period of wellness as definedby DSM IV criteria;

• MADRS score ≥22 at 2 separate baseline visits, rated by 2 separate psychiatrists;

• Global Assessment of Functioning (GAF) score <50;

• Mini-mental state examination (MMSE) score >24;

• No change in current antidepressant medication regimen or medication free for atleast 4 weeks prior to study entry;

• Able to give informed consent in accordance with institutional policies;

Exclusion Criteria:

• A diagnosis of bipolar I or bipolar II disorder by DSM-IV-TR criteria, derived fromthe MINI;

• Meets criteria for borderline or antisocial personality disorder in the last 12months by DSM-IV-TR criteria, derived from the Cluster B Personality DisordersSections 301.7 - 301.83, preferably screened via Structured Clinical Interview forDSM-IV Personality Disorders (SCID-II) at Baseline visit (optional);

• In the current depressive episode, has been diagnosed with General Anxiety Disorder (GAD) - as defined by the DSM-IV-TR, and GAD is the primary diagnosis;