Effect of tDCS Timing on Safety Memory in PTSD

The primary purpose of this study is to investigate the effects of tDCS timing on extinction memory in PTSD. A total of 90 participants will be randomized equally across one of three groups:

1. One group receiving active stimulation during extinction followed by sham stimulation during consolidation
2. One group receiving sham stimulation during extinction followed by active stimulation during consolidation
3. One group receiving sham stimulation both during extinction and consolidation

This study also includes an online sub-study (Aim 2) focused on contextual processing along the PTSD spectrum. The online study tests if there is an association between threat and non-threat learning in contextual and non-contextual situations. A maximum of 500 participants will be recruited using an online, panel-based platform.

Study Overview

• Status: Completed
• Conditions: PTSD
• Intervention / Treatment: Device: transcranial direct current stimulation

Detailed Description

This is a three-arm study composed of four to five visits over an approximate period of three weeks. Up to ninety participants are exposed to a fear conditioning, extinction, and extinction memory paradigm at three separate study visits (day 3-5); one of these study visits will include active or sham transcranial direct current stimulation (tDCS) for a period of 15 minutes. Skin conductance reactivity during extinction memory (day 5) is the primary outcome. Additional study procedures include a screening period (day 1) and two optional MRI scans, one done on study day 2 and one done on study day 5. As the completion of MRI scans are an optional study component, MRI-related data is not reported here.

SUB-STUDY: The objective of this sub-study is to test performance differences between contextual and non-contextual processing in individuals across the PTSD spectrum using an online, panel-based platform. Following a within-subjects study design, up to 500 adult participants, 18-89 years, will be asked to complete experimental tasks that assess contextual (configural) and non-contextual (elemental) threat and non-threat learning. They will also provide demographic information (age, sex, ethnicity) and complete questionnaires assessing self-reported PTSD, anxiety, and depression severity. As this sub-study does not reflect a randomized clinical trial (no groups, no randomization, no intervention), no further information is reported here.

• Study Type: Interventional
• Enrollment (Actual): 62
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Rhode Island
    • Providence, Rhode Island, United States, 02906
      • Butler Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 70 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Primary diagnosis of PTSD, assessed by the Structured Clinical Interview of DSM-5 (SCID);
2. aged 18-70;
3. ability to speak, read, write, and understand English sufficiently well to complete study procedures and provide informed consent;
4. Stable psychiatric medication use or treatment for at least 6 weeks.

Exclusion Criteria:

1. Lifetime history of psychotic or bipolar disorder;
2. Current moderate or severe substance use disorder; if mild, not under the influence at time of study participation;
3. Acute suicidal or homicidal ideation as detected on screening instruments or in the investigator team's opinion, is likely to attempt suicide within 6 months;
4. current (or past) significant neurological disorder, injury, or other intracranial pathology including severe traumatic brain injury or lifetime history of a) seizure disorder b) primary or secondary CNS tumors c) stroke or d) cerebral aneurysm;
5. lifetime history of moderate or, current unstable medical conditions;
6. Any problems that would interfere with study participation, including MRI- or tDCS-related contraindications (e.g., implanted metallic devices/substances, metallic tattoos, pregnancy, claustrophobia, holes in the skull, skin abnormalities under stimulation sites), or indication of colorblindness, or presence of any other condition or circumstance that, in the opinion of the investigator team, has the potential to prevent study completion and/or inability to schedule visit days within the allotted time, and/or to have a confounding effect on outcome assessments.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Active tDCS during extinction learning followed by sham tDCS during consolidation; Active tDCS will be applied during the extinction learning phase followed by sham tDCS during the consolidation phase.	Device: transcranial direct current stimulation; Active tDCS will consist of 15 minutes of 2 mA intensity once, either applied during or after extinction learning.
Active Comparator: Sham tDCS during extinction learning followed by active tDCS during consolidation; Sham tDCS will be applied during the extinction learning phase followed by active tDCS during the consolidation phase.	Device: transcranial direct current stimulation; Active tDCS will consist of 15 minutes of 2 mA intensity once, either applied during or after extinction learning.
Sham Comparator: Sham tDCS during extinction learning followed by sham tDCS during consolidation; Sham tDCS will be applied during the extinction learning phase followed by sham tDCS during the consolidation phase.	Device: transcranial direct current stimulation; Active tDCS will consist of 15 minutes of 2 mA intensity once, either applied during or after extinction learning.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Skin Conductance Responses	Main protocol: Threat reactivity as quantified by skin conductance responses to a conditioned and subsequently extinguished stimulus versus a never conditioned stimulus.	Study visit day 4: during administration of fear extinction memory.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Neural activity	Neural activity will be measured via MRI scans.	MRI scans will collected on day 2 of study protocol.

Collaborators and Investigators

• Sponsor: Butler Hospital
• Collaborators: National Institute of General Medical Sciences (NIGMS)
• Investigators: Principal Investigator: Benjamin Greenberg, PhD, MD, Butler Hospital

Publications and helpful links

General Publications

• Faucher CR, Doherty RA, Philip NS, Harle ASM, Cole JJE, Van't Wout-Frank M. Is there a neuroscience-based, mechanistic rationale for transcranial direct current stimulation as an adjunct treatment for posttraumatic stress disorder? Behav Neurosci. 2021 Dec;135(6):702-713. doi: 10.1037/bne0000487. Epub 2021 Aug 2.

Study record dates

Study Major Dates

• Study Start (Actual): November 22, 2019
• Primary Completion (Actual): January 31, 2024
• Study Completion (Actual): January 31, 2024

Study Registration Dates

• First Submitted: October 31, 2019
• First Submitted That Met QC Criteria: November 4, 2019
• First Posted (Actual): November 5, 2019

Study Record Updates

• Last Update Posted (Estimated): October 21, 2025
• Last Update Submitted That Met QC Criteria: October 7, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: PTSD; tDCS; fear conditioning; safety memory; ventromedial prefrontal cortex; context processing
• Additional Relevant MeSH Terms: Trauma and Stressor Related Disorders; Mental Disorders; Stress Disorders, Traumatic; Stress Disorders, Post-Traumatic; Therapeutics; Behavioral Disciplines and Activities; Electric Stimulation Therapy; Convulsive Therapy; Psychiatric Somatic Therapies; Electroshock; Psychological Techniques; Transcranial Direct Current Stimulation
• Other Study ID Numbers: 1346426-5; P20GM130452 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No