Cognitive Enhancement in Recurrent Depression (The COG-D-R Study)

May 12, 2026 updated by: Sarah Szymkowicz, Vanderbilt University Medical Center

The goal of this clinical trial is to learn if a combination of non-drug treatments works to benefit memory, thinking, and brain functioning in older individuals with recurrent depression. The non-drug approaches the investigators are studying include transcranial direct current stimulation (tDCS) and computerized cognitive training. tDCS uses small currents of electricity on the forehead to potentially stimulate your brain's ability to process and learn. Computerized cognitive training uses tablet games to improve memory and thinking.

In this study, two different cognitive training programs are being investigated, both of which are stimulating and designed to engage brain activity. One that is believed to be a specific treatment for depression, while the other provides extra stimulation for the brain that is non-specific. Two different tDCS parameters - active stimulation and sham (or placebo) stimulation - are also being investigated.

Participants will be randomized to one of three study groups:

  1. Depression cognitive training treatment with active brain stimulation
  2. Depression cognitive training treatment with sham brain stimulation
  3. Non-specific cognitive training treatment with sham brain stimulation

The main questions this clinical trial aims to answer are:

  • Does "depression cognitive training treatment with active brain stimulation" benefit thinking and memory more so than the other treatments?
  • Does "depression cognitive training treatment with active brain stimulation" benefit brain functioning more so than the other treatments?

Participants will:

  • Complete several baseline and post-intervention visits at the research center for checkups and tests over the course of 3-4 months.
  • Visit the research center daily for 4 weeks to complete their assigned treatment.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The purpose of this study is to determine whether stepwise engagement of the frontal lobe across randomized groups (active tDCS+depression cognitive training > sham tDCS+depression cognitive training > sham tDCS+non-specific cognitive training) will result in progressively greater improvements in executive functions and memory, as well as intrinsic functional connectivity of the Executive Control Network (ECN), in older adults with recurrent depression. The investigators will randomize 69 elderly depressed outpatients into one of three conditions daily over 4-weeks. Psychiatric and neuropsychological evaluations, as well as multimodal neuroimaging (focused on the ECN) will be obtained at baseline and following intervention completion to look at acute and long-term effects.

Study Type

Interventional

Enrollment (Estimated)

69

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • United States
    • Tennessee
      • Nashville, Tennessee, United States, 37212
        • Vanderbilt University Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Age > 60 years
  • Evidence of executive dysfunction via SUBJECTIVE COMPLAINTS (At least one subdomain of the Behavior Rating Inventory of Executive Function in Adults (BRIEF-A) at T > 65, or At least one average score of > 1.5 on Planning, Organization, or Attention subdomains of the Everyday Cognition Scale (ECog)) or OBJECTIVE PERFORMANCE (At least one demographically adjusted z-score > -1.0 SD below the mean on a measure of executive functioning (Digits backward, Trails B, or total Verbal Fluency) on the National Alzheimer's Coordinating Center (NACC) Uniform Data Set 3.0).
  • DSM-5 diagnosis of a current or past (within last 3 years) depressive episode (e.g., Major Depressive Disorder (MDD), Persistent Depressive Disorder (PDD)) via the using the Structured Clinical Interview for DSM-5 Disorders (SCID-5).
  • Presence of 2 or more lifetime depressive episodes to be considered "recurrent."
  • Either stable antidepressant regimen for at least 6 weeks or no current antidepressant treatment (no plans to change treatment over course of study).
  • Fluent in English

Exclusion Criteria:

  • Other psychiatric conditions via the SCID-5 (including history of bipolar disorder and psychosis, excluding comorbid anxiety disorders)
  • Severe depression (MADRS score > 29)
  • Acute suicidality on clinical evaluation by study clinician and via response on MADRS item 10 (score of 4 or more would require further assessment)
  • Acute grief (occurring within past month)
  • History of alcohol use disorder or substance use disorder of moderate or greater severity in the last 12 months
  • Medications that would significantly interfere with tDCS effects (i.e., sodium channel blockers, GABA-ergic or glutamatergic drugs; see Appendix B for exclusionary list)40
  • Primary neurological disorder (e.g., epilepsy, brain tumor, Parkinson's disease, Alzheimer's disease, dementia diagnosis)
  • Montreal Cognitive Assessment (MoCA) < 23
  • Primary amnestic cognitive profile (>1.5 SD below demographically-adjusted mean on NACC memory measures in context otherwise normal cognitive profile, or per clinician judgement)
  • Any physical or intellectual disability affecting ability to complete assessments
  • Unstable medical illness needing urgent treatment
  • MRI contraindications
  • Electroconvulsive therapy (ECT) or transcranial magnetic stimulation (TMS) in last 2 months
  • Current involvement in psychotherapy
  • Current involvement in other research studies (including but not limited to: neuromodulation [TMS or tDCS] or investigational drug studies). Observational studies [without intervention] are acceptable.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Triple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Depression Cognitive Training + Active Stimulation
This arm receives the depression cognitive training combined with active tDCS.
Device: tDCS (active stimulation)
A Soterix Clinical Trials Direct Current Stimulator will apply 20 minutes of 2.0 milliamps (mA) direct current through two bicarbon rubber electrodes encased in saline soaked 5 cm x 7 cm sponges (8 cc of 0.9% saline solution per sponge) placed over the frontal cortices at F3 and F4 (via 10-20 system).
Behavioral: Depression Cognitive Training
Computerized cognitive training targeting the underlying cerebral networks associated with depression.
Experimental: Depression Cognitive Training + Sham Stimulation
This arm receives the depression cognitive training combined with sham tDCS.
Device: tDCS (sham stimulation)
Sham stimulation will be performed with the same device and all procedures will be identical except for the duration of stimulation. Participants will receive 30 seconds of 2 mA of direct current stimulation at the beginning of the session. Participants habituate to the sensation of tDCS within 30-60 seconds of stimulation. This procedure provides the same sensation of tDCS without the full duration of stimulation, making it a highly effective sham procedure.
Behavioral: Depression Cognitive Training
Computerized cognitive training targeting the underlying cerebral networks associated with depression.
Experimental: Non-Specific Cognitive Training + Sham Stimulation
This arm receives the non-specific cognitive training combined with sham tDCS.
Device: tDCS (sham stimulation)
Sham stimulation will be performed with the same device and all procedures will be identical except for the duration of stimulation. Participants will receive 30 seconds of 2 mA of direct current stimulation at the beginning of the session. Participants habituate to the sensation of tDCS within 30-60 seconds of stimulation. This procedure provides the same sensation of tDCS without the full duration of stimulation, making it a highly effective sham procedure.
Behavioral: Non-Specific Cognitive Training
Computerized cognitive training that provides extra stimulation for the brain that is non-specific.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
NIH Examiner
Time Frame: Baseline, Following completion of the 4-week intervention, 3-month Post-Intervention
This objective cognitive test battery assesses a range of executive functions (working memory, inhibition, set shifting, fluency, and planning). The investigators will examine intervention-related change its Executive Composite Score (primary outcome), and subcomposite (Cognitive Control, Working Memory, and Fluency; secondary outcomes) scores, where higher scores indicate better performance.
Baseline, Following completion of the 4-week intervention, 3-month Post-Intervention
Resting state fMRI functional connectivity
Time Frame: Baseline, Following completion of the 4-week intervention
Functional connectivity from resting state fMRI will be processed using the CONN toolbox for connectivity, incorporating the Shaeffer network atlases to improve peer-research supported network usage in addition to the standard CONN atlases. A priori ROI-to-ROI analyses will be used to determine whether average connectivity changes in the Executive Control Network differs by treatment group. Analyses will control for multiple comparisons at false discovery rate (FDR) < 0.05.
Baseline, Following completion of the 4-week intervention

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Montgomery Asberg Depression Rating Scale
Time Frame: Baseline and weekly thereafter, Following completion of the 4-week intervention, 3-Month Post-Intervention
The MADRS is a 10-item clinician-rated measure of depression severity, with higher scores indicating greater symptom severity. We will look at change in depression severity over the course of the intervention by treatment arm in Exploratory Analyses.
Baseline and weekly thereafter, Following completion of the 4-week intervention, 3-Month Post-Intervention

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Vanderbilt University Medical Center

Collaborators

National Institute of Mental Health (NIMH)

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 1, 2026

Primary Completion (Estimated)

May 30, 2028

Study Completion (Estimated)

June 30, 2028

Study Registration Dates

First Submitted

March 23, 2026

First Submitted That Met QC Criteria

April 6, 2026

First Posted (Actual)

April 14, 2026

Study Record Updates

Last Update Posted (Actual)

May 15, 2026

Last Update Submitted That Met QC Criteria

May 12, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 251809

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

product manufactured in and exported from the U.S.

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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