Of the estimated 30 million Americans who suffer from Major Depressive Disorder, approximately 10% are considered treatment resistant. Deep brain stimulation (DBS) to a region of the brain called the subcallosal cingulate (SCC) is an emerging strategy for treatment resistant depression (TRD), which involves placement of electrodes in a specific region of the brain and stimulating that area with electricity. This is believed to reset the brain network responsible for symptoms and results in a significant antidepressant response. A series of open-label studies have demonstrated sustained, long-term antidepressant effects in 40-60% of patients who received this treatment. A challenge to the effective dissemination of this fledgling treatment is the absence of biomarkers (objective, measureable indications of the state of the body and brain) to guide device placement and select stimulation parameters during follow-up care.

By using an experimental prototype DBS device called the Summit RC+S (Medtronic, Inc) which has the ability to both deliver stimulation to and record electrical signals directly from the brain, this study aims to identify changes in local field potentials (LFPs), specific electrical signals that are thought to represent how the brain communicates information from one region to another, to see how this relates to DBS parameter settings and patient depressive symptomatology. The goal of this study is to study LFPs before and during active DBS stimulation to identify changes that correlate with the antidepressant effects of SCC DBS.

The study team will recruit 10 patients with TRD and implant them with the Summit RC+S system. Participants will be asked to complete short questionnaires and collect LFP data twice daily for the first year of the study, as well as have weekly in person research procedures and assessments with the study team for up to one year. These include meetings with the study psychiatrist, psychologist, symptom ratings, and periodic EEGs (scalp brainwave recordings). A brief discontinuation experiment will be conducted after 6 months of stimulation, in which the device will be turned off and patterns of LFP changes will be recorded. The entire study is expected to last about 10 years, which is the expected life of the battery that powers the device. All participants are required to live in the New York metropolitan area for the first two years of the study.

Inclusion Criteria:

• Age 25-70 years old.

• Ability to provide written informed consent.

• Lives within commuting distance to New York City and study location (Mount Sinai West Hospital)

• Primary psychiatric diagnosis of Major Depressive Disorder (MDD), either single episode or recurrent type, without psychotic features, currently experiencing a Major Depressive Episode (MDE), as diagnosed by Structured Clinical Interview for DSM IV-TR (SCID). Two independent psychiatrists will confirm the diagnosis.

• Current depressive episode of at least two years duration OR a history of more than 3 lifetime depressive episodes.

• Minimum score at study entry of 20 on the 17-item Hamilton Depression Rating Scale (HDRS-17)

• Average pre-operative HDRS-17 score of 20 or greater (averaged over four weekly pre-surgical evaluations during the four weeks prior to surgery) and an average pre-operative HDRS-17 score no more than 30% lower than the baseline screening HDRS-17 score.

• A maximum Global Assessment of Functioning of 50 or less.

• Confirmed to have treatment-resistant depression (TRD). Treatment-resistance will be defined as:

  1. Failure to respond to a minimum of four different antidepressant treatments (including at least three medications from at least three different drug classes), evidence-based psychotherapy, or electroconvulsive therapy (ECT) administered at adequate doses and duration during the current episode. We will require documentation (i.e., statement from the treating psychiatrist) that a treatment trial has failed (either no response to maximum tolerable doses for a minimum of 4 weeks, or side effects at sub-maximal doses) as coded by a revised Antidepressant Treatment History Form (ATHF). The study investigators will confirm each treatment via review of records from referring psychiatrists and/or pharmacy records.
  2. Failure or intolerance of an adequate course of electroconvulsive therapy (ECT) during any episode (confirmed by medical records) or not receiving ECT due to a reason considered valid by the study psychiatrist. Such reasons might include lack of availability of ECT providers in the patient's location, concern regarding the impact of cognitive side effects of ECT on current ability to work or function, or inability to obtain third-party payment for ECT. Additionally, it is recognized that the probability that a patient who has failed four medications in the current episode will achieve a lasting response with ECT is about 18% (60% probability of an acute response and 30% of maintaining response for at least 24 weeks); patients who have refused ECT because they feel the chance of benefit does not outweigh the risks associated with ECT will be considered eligible.

• Able to undergo preoperative MRI

• Have a designated caregiver available to assist in compliance with study procedures

• Willing and able to comply with all study-related appointments and procedures

Exclusion criteria:

• Other Axis I comorbid conditions
• Active suicidal ideation with intent, suicide attempt within the last six months, more than three suicide attempts within the last two years, or serious suicide risk as determined by the study psychiatrists
• Other primary neurological disorders or unstable medical illness
• Conditions requiring anticoagulant therapy which cannot be discontinued for the perioperative period, as required
• Conditions requiring MRI scans or diathermy
• Pregnancy or plan to come pregnant during the study
• Contraindications for general anesthesia, neurosurgery, or an MRI scan
• Currently implanted with a cardiac pacemaker / defibrillator or other implanted electrical device which may interfere with DBS stimulator or the function of which may be impacted by its implantation.
• Patients who lack the capacity for proper device usage and maintenance, in the opinion of the research team

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices).

Beginning 9 months and ending 36 months following article publication.

Investigators whose proposed use of the data has been approved by an independent review committee (learned intermediary) identified for this purpose may request access to individual participant data meta-analysis. To gain access, data requestors will need to sign a data access agreement. Data are available for 5 years at a third party website (https://dabi.loni.usc.edu).

N/A. This is open label study.