The investigators will investigate in a sham controlled staggered onset design antidepressant effects and safety of deep brain stimulation (DBS) to the superolateral branch of the main medial forebrain bundle (slMFB).

The target point for DBS in major depression disorder is located lateral to the ventral tegmental area (VTA) in the midbrain at the branching point of the superolateral branch (slMFB) from the main medial forebrain bundle (MFB).

The exact stimulation coordinates are:

Montreal Neurologic Institute brain 152 coordinates (MNI152 coordinates):

left: x(lat.)=-5, y(ap)=-14, z(vert.)=-8 right: x(lat.)=5, y(ap)=-14, z(vert.)=-9

Mid-commissural point coordinates (MCP coordinates):

eft: x(lat.)=-6, y(ap)=-1, z(vert.)=-6 right: x(lat.)=4, y(ap)=-1, z(vert.)=-7

All coordinates refer to the MNI152 brain.

Legend:

slMFB = superolateral branch of medial forebrain bundle lat. = lateral, ap= anteroposterior, vert. = vertical.

More information can be found at: http://goo.gl/n9sWV

Inclusion Criteria:

• Major depression (MD), severe, unipolar

• German mother tongue

• Age 20 to 75 Years

• Hamilton Depression Rating Scale (HRSD24) score of > 21

• Global Assessment of Function (GAF) score of < 45

• At least 4 episodes of depression or chronic episode > 2 years

• Failure to respond to

  • adequate trials (>5 weeks at the maximum recommended or tolerated dose) of primary antidepressants from at least 3 different classes;
  • adequate trials (>3 weeks at the usually recommended or maximum tolerated dose) of augmentation/combination of a primary antidepressant using at least 2 different augmenting/combination agents (lithium, T3, stimulants, neuroleptics, anticonvulsants, buspirone, or a second primary antidepressant);
  • an adequate trial of electroconvulsive therapy (ECT) (>6 bilateral treatments) and; an adequate trial of individual psychotherapy (>20 sessions with an experienced psychotherapist)

• Able to give written informed consent

• Compliance to participate in the study

• Drug free or on stable drug regimen at least 6 weeks before study entry

Exclusion Criteria:

• Current or past non-affective psychotic disorder
• Any current clinically significant neurological disorder or medical illness affecting brain function, other than motor tics or Gilles de la Tourette syndrome
• Any clinically significant abnormality on preoperative magnetic resonance imaging (MRI)
• Any surgical contraindications to undergoing DBS
• Current or unstably remitted substance abuse (aside from nicotine)
• Pregnancy and women of childbearing age not using effective contraception
• History of severe personality disorder
• Acute suicidal tendency