Obsessive-Compulsive DisorderNCT05521074

Transcranial Direct Current Stimulation Potentiation of Fear Extinction in OCD

A study testing Active tDCS in people with Obsessive-Compulsive Disorder, run by Massachusetts General Hospital at 1 site in United States.

Completed

Finished. The study has ended and is not enrolling. Results may be posted on the official record.

Official record

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Trial summary

The investigators want to learn more about how human beings learn not to fear and the impact of changing the fear network in the brain using transcranial Direct Current Stimulation (tDCS) in individuals with obsessive compulsive disorder (OCD). Read more about this study

Who is it for?: Ages 18 to 60 years
Conditions the study is for: Obsessive-Compulsive Disorder
What is being tested?: Active tDCS
Type of treatment: Medical device
Could I receive a placebo?: Yes, some participants may receive a placebo
How many people: 86 participants
Where: 1 siteUnited States
Study dates: 15 Sep 2022to 31 Jul 2025
Phase: Interventional
Are there results?: Yes, posted in the registrySummary in the doctors' view

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

Ages 18 to 60 years
All sexes
No healthy volunteers
Adult

Who may be able to join

Fluent in English, willing to provide informed consent, and willing to comply with the study protocol
Primary OCD that causes at least moderate distress and/or impairment (Y-BOCS total score ≥ 16)
Comfortable and capable of using a computer and completing computerized tasks

Who cannot join

History of head injury resulting in prolonged (i.e., >1h) loss of consciousness and/or neurological sequelae; history of stroke; signs of increased intracranial pressure; prior neurosurgical procedure (e.g., DBS, aneurysm clips)
Contraindications to participate in tDCS including: metallic implants in head or neck; ventriculoperitoneal (VP) shunts; pacemakers; pregnancy; epilepsy.
Current or history of neurologic or psychiatric disease (e.g., mental retardation, dementia, brain damage, or other cognitive impairment) that would interfere with ability to participate in the study
Impaired (or uncorrected) vision that would interfere with participation.
Current clinically significant suicidality that requires psychiatric hospitalization, as indicated by clinical judgment.
Current substance use disorder (within the past 12 months)

Show all 10Show fewer

Lifetime manic episode or psychosis
Documented resistance to 4 or more valid pharmacological trials and previous treatment with ≥12 sessions of cognitive behavioral therapy for OCD with no response (or worsening symptoms)
Use of most psychotropic medications (e.g., SSRIs and atypical antipsychotics) will be allowed. However, use of benzodiazepines within 2 weeks prior to the study is exclusionary (and participants will be asked to refrain from use of such medications during the study as they may interfere with the fear extinction paradigm).
Unable to obtain low enough impedance values to ensure safe and effective application of tDCS/EEG.

Trial locations and contacts

1 site in 1 country.

United States1 site

Massachusetts General Hospital
Boston, Massachusetts, 02114

Other trials in United States

About this study

Official title: Transcranial Direct Current Stimulation Potentiation of Fear Extinction in OCD: Towards Rational Design of Combination Therapies

Read the detailed description

To address this question behaviorally and biologically, the investigators will use a, 2-day fear extinction paradigm while measuring behavioral psychophysiology (skin conductance response [SCR]) and neurophysiology (electroencephalography [EEG]). On Day 1 participants will undergo 1) habituation, 2) fear conditioning, and 3) extinction learning. On Day 2 they will undergo 4) extinction recall, and 5) reinstatement. SCR and EEG will be measured in both sessions. The investigators propose to investigate whether inhibitory tDCS to the pre-SMA before, during, or after fear extinction significantly 1) enhances the recall of extinction learning and 2) reduces fronto-medial theta power during extinction recall. Participants will be randomized to one of the following four conditions: active tDCS before, during, or after extinction learning, or sham tDCS. The fear extinction paradigm serves as a proxy of exposure-based CBT for OCD. Defining the combination protocol that optimally and significantly increases extinction recall behaviorally (psychophysiology) in OCD, will have critical implications for the mechanistically informed development of tDCS-augmented CBT for OCD. EEG measures will provide a response biomarker to characterize target engagement neurophysiologically. This is particularly relevant given EEG's ease of use, relatively low cost, and potential for greater translation to the clinic. Also, the higher signal-to-noise ratio (SNR) of EEG compared to SCR is a strength. Taken together, these data should reveal treatment targets, define optimal therapeutic protocols, and provide the foundation for a future clinical trial to test the synergistic efficacy of combined tDCS-CBT for OCD.

Conditions: Obsessive-Compulsive Disorder
Being tested: Active tDCS, Sham tDCS
Keywords: Obsessive-Compulsive Disorder, OCD, Fear extinction, tDCS, transcranial Direct Current Stimulation, Randomized controlled trial, Fear conditioning
Medical subject headings: Obsessive-Compulsive Disorder

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

Active tDCSDevice
The investigators will use commercially available tDCS equipment (Neuroelectrics©, Barcelona, Spain). The cathode will be placed over the pre-SMA using the 10-20 EEG system and the anode will be on the right deltoid.
Sham tDCSDevice
The investigators will use commercially available tDCS equipment (Neuroelectrics©, Barcelona, Spain). The cathode will be placed over the pre-SMA using the 10-20 EEG system and the anode will be on the right deltoid. tDCS will not be active in this condition.

Study groups in NCT05521074
Study group	Role	What they receive
Active tDCS administered before extinction phase	Experimental	The investigators will stimulate using 2mA of direct current during 20 min before the extinction phase of the fear conditioning and extinction paradigm. Receives: Device: Active tDCS
Active tDCS administered during extinction phase	Experimental	The investigators will stimulate using 2mA of direct current during 20 min during the extinction phase of the fear conditioning and extinction paradigm. Receives: Device: Active tDCS
Active tDCS administered after extinction phase	Experimental	The investigators will stimulate using 2mA of direct current during 20 min after the extinction phase of the fear conditioning and extinction paradigm. Receives: Device: Active tDCS
Sham tDCS	Sham comparator	Sham will consist of a ramp up and down of activity (from 0 to 2mA and back to 0mA) in the first 30sec and again in the last 30 sec of the 20min stimulation period (which will occur before/during/after the extinction phase). No active tDCS will occur. Receives: Device: Sham tDCS

What is being measured

The primary outcome is the main question the study is designed to answer.

Difference in Frontomedial Theta Power (EEG) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During Extinction Recall
Greater reduction in the difference in frontomedial theta event-related spectral perturbation (ERSP) between CS+ vs CS- indicates more complete neural extinction of the conditioned fear response, reflecting diminished differential threat processing such that the previously conditioned stimulus is being processed more similarly to the safe stimulus.
Measured: Extinction Recall Phase (Day 2)
Difference in the Square Root Skin Conductance Response (SCR) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During the First 12 Trials of Extinction Recall
Higher skin conductance (microSiemens) indicates greater fear intensity.
Measured: Extinction Recall Phase (Day 2)

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

15 Sep 202231 Jul 2025

First posted30 Aug 2022
Study start15 Sep 2022
Primary completion31 Jul 2025
Study completion31 Jul 2025

Resources

Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
Other trials for Obsessive-Compulsive DisorderStudies of the same condition, open and under way.
More trials run by Massachusetts General HospitalThe sponsor's other registered studies.
What the trial phases meanHow a treatment moves from first tests in people to approval.

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design

Study type: Interventional
Phase: Phase N/A
Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Triple blind
Who is masked: Participant, Investigator, Outcomes assessor
Enrolment: 86 participants (actual)

IDs, dates and publications

ClinicalTrials.gov ID: NCT05521074
Sponsor's protocol ID: 2022P001065
Status last verified: Jul 2026
First submitted: 26 Aug 2022
Last updated: 4 Sep 2026
Results posted: Yes, on ClinicalTrials.gov
Data monitoring committee: Yes
FDA-regulated drug: No
FDA-regulated device: Yes
Individual data sharing: No: The investigators do not have specific plans to share individual participant data in order to preserve the confidentiality of our participants. Any data that is shared would only be done so after executing a formal Data Use Agreement from Massachusetts General Hospital.

Want to know more?

The sponsor has not listed a contact. The official record may have more details.

Talk to your doctor first and take this page with you. Only the study team can confirm whether you can join.

Questions to ask the study team

What is the study trying to find out?
What would I need to do, and how often would I visit?
Could I receive a placebo instead of the treatment?
What are the possible risks and benefits for me?
Will it cost me anything? Are travel or time paid for?
Can I keep seeing my own doctor during the study?
What happens when the study ends?

See locations

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All Obsessive-Compulsive Disorder trials

Study at a glance

From the registry record, last updated by the sponsor on 4 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.

Official title: Transcranial Direct Current Stimulation Potentiation of Fear Extinction in OCD: Towards Rational Design of Combination Therapies
ClinicalTrials.gov ID: NCT05521074
Acronym / sponsor ID: 2022P001065
Conditions: Obsessive-Compulsive Disorder
Keywords: Obsessive-Compulsive Disorder, OCD, Fear extinction, tDCS, transcranial Direct Current Stimulation, Randomized controlled trial, Fear conditioning
Study type: Interventional
Recruitment status: Completed
Enrolment: 86 participants (actual)
Lead sponsor: Massachusetts General HospitalUniversity, hospital or other
Collaborators: Foundation for OCD Research
Study start: 15 Sep 2022 (actual)
Primary completion: 31 Jul 2025 (actual)
Study completion: 31 Jul 2025 (actual)
First posted: 30 Aug 2022 (actual)
Results: Posted 4 Sep 2026

Clinical summary

The research question as the sponsor registered it. This describes what the study plans to test, not what it found.

Detailed description

Study design

Primary purpose: Other
Allocation: Randomised
Intervention model: Parallel groups
Masking: Triple blind (participant, investigator, outcomes assessor)
Number of arms: 4

Arm	Type	Receives
Active tDCS administered before extinction phase	Experimental	Device: Active tDCSThe investigators will stimulate using 2mA of direct current during 20 min before the extinction phase of the fear conditioning and extinction paradigm.
Active tDCS administered during extinction phase	Experimental	Device: Active tDCSThe investigators will stimulate using 2mA of direct current during 20 min during the extinction phase of the fear conditioning and extinction paradigm.
Active tDCS administered after extinction phase	Experimental	Device: Active tDCSThe investigators will stimulate using 2mA of direct current during 20 min after the extinction phase of the fear conditioning and extinction paradigm.
Sham tDCS	Sham comparator	Device: Sham tDCSSham will consist of a ramp up and down of activity (from 0 to 2mA and back to 0mA) in the first 30sec and again in the last 30 sec of the 20min stimulation period (which will occur before/during/after the extinction phase). No active tDCS will occur.

Who may qualify

Ages: 18 to 60 years
Sex: All
Healthy volunteers: Not accepted
Age groups: Adult

Key inclusion criteria (3 listed)

Fluent in English, willing to provide informed consent, and willing to comply with the study protocol
Primary OCD that causes at least moderate distress and/or impairment (Y-BOCS total score ≥ 16)
Comfortable and capable of using a computer and completing computerized tasks

Key exclusion criteria (10 listed)

History of head injury resulting in prolonged (i.e., >1h) loss of consciousness and/or neurological sequelae; history of stroke; signs of increased intracranial pressure; prior neurosurgical procedure (e.g., DBS, aneurysm clips)
Contraindications to participate in tDCS including: metallic implants in head or neck; ventriculoperitoneal (VP) shunts; pacemakers; pregnancy; epilepsy.
Current or history of neurologic or psychiatric disease (e.g., mental retardation, dementia, brain damage, or other cognitive impairment) that would interfere with ability to participate in the study
Impaired (or uncorrected) vision that would interfere with participation.
Current clinically significant suicidality that requires psychiatric hospitalization, as indicated by clinical judgment.

Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.

Interventions

Intervention	Type	Arms
Active tDCSThe investigators will use commercially available tDCS equipment (Neuroelectrics©, Barcelona, Spain). The cathode will be placed over the pre-SMA using the 10-20 EEG system and the anode will be on the right deltoid.	Device	Active tDCS administered after extinction phase, Active tDCS administered before extinction phase, Active tDCS administered during extinction phase
Sham tDCSThe investigators will use commercially available tDCS equipment (Neuroelectrics©, Barcelona, Spain). The cathode will be placed over the pre-SMA using the 10-20 EEG system and the anode will be on the right deltoid. tDCS will not be active in this condition.	Device	Sham tDCS

Primary outcome

Difference in Frontomedial Theta Power (EEG) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During Extinction Recall
Time frame: Extinction Recall Phase (Day 2)
Greater reduction in the difference in frontomedial theta event-related spectral perturbation (ERSP) between CS+ vs CS- indicates more complete neural extinction of the conditioned fear response, reflecting diminished differential threat processing such that the previously conditioned stimulus is being processed more similarly to the safe stimulus.
Difference in the Square Root Skin Conductance Response (SCR) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During the First 12 Trials of Extinction Recall
Time frame: Extinction Recall Phase (Day 2)
Higher skin conductance (microSiemens) indicates greater fear intensity.

Results and safety

Results posted to the registry on 4 Sep 2026, as reported by the sponsor. Figures are copied from the record, not re-analysed. Full results on ClinicalTrials.gov.

Participant flow

Group	Started	Completed
Active tDCS Administered Before Extinction Phase	21	21
Active tDCS Administered During Extinction Phase	22	19
Active tDCS Administered After Extinction Phase	21	21
Sham tDCS	22	22

Primary outcome: Difference in Frontomedial Theta Power (EEG) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During Extinction Recall

Time frame: Extinction Recall Phase (Day 2). Mean (Standard Deviation). Unit: Decibel (dB)

Measure	Active tDCS Administered Before Extinction Phase n = 19	Active tDCS Administered During Extinction Phase n = 17	Active tDCS Administered After Extinction Phase n = 19	Sham tDCS n = 20
Value	-0.30 (1.4)	-0.83 (2.0)	-0.26 (1.8)	-0.37 (1.8)

Active tDCS Administered Before Extinction Phase vs Active tDCS Administered During Extinction Phase vs Active tDCS Administered After Extinction Phase vs Sham tDCS: Omnibus F-statistic: 0.39, p = 0.76, Linear Mixed Model

Population analysed: Participants (n=11) were excluded from EEG analyses for the following reasons: poor data quality (n=6); participant dropped out (n=3); EEG data/triggers missing (n=2).

Primary outcome: Difference in the Square Root Skin Conductance Response (SCR) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During the First 12 Trials of Extinction Recall

Time frame: Extinction Recall Phase (Day 2). Mean (Standard Deviation). Unit: microSiemens

Measure	Active tDCS Administered Before Extinction Phase n = 16	Active tDCS Administered During Extinction Phase n = 16	Active tDCS Administered After Extinction Phase n = 18	Sham tDCS n = 17
Value	0.13 (0.35)	0.24 (0.42)	0.17 (0.38)	0.24 (0.43)

Active tDCS Administered After Extinction Phase vs Sham tDCS: Beta Estimate: -0.04 (95% CI -0.14 to 0.05), p = 0.37, Linear Mixed Effects Regression
Active tDCS Administered Before Extinction Phase vs Sham tDCS: Beta Estimate: -0.10 (95% CI -0.20 to -0.01), p = 0.037, Linear Mixed Effects Regression
Active tDCS Administered During Extinction Phase vs Sham tDCS: Beta Estimate: 0.06 (95% CI -0.03 to 0.16), p = 0.192, Linear Mixed Effects Regression

Population analysed: Participants (n=19) were excluded from SC analyses for the following reasons: poor data quality (n=6); participant dropped out (n=3); SC equipment error (n=1); SC non-responders (i.e., individuals with a mean unconditioned SCR of less than 0.1 μS; n=9).

Adverse events

Time frame: From enrollment (virtual consent) until final study visit (Day 2). Other adverse events reported at 5% frequency or more

Group	Serious adverse events	Other adverse events	Deaths
Active tDCS Administered Before Extinction Phase	0 of 21 (0%)	21 of 21 (100%)	0 of 21
Active tDCS Administered During Extinction Phase	0 of 22 (0%)	21 of 22 (95.5%)	0 of 22
Active tDCS Administered After Extinction Phase	0 of 21 (0%)	21 of 21 (100%)	0 of 21
Sham tDCS	0 of 22 (0%)	21 of 22 (95.5%)	0 of 22

Loading the posted results from ClinicalTrials.gov…

Research links

Official record on ClinicalTrials.govLast updated by the sponsor 4 Sep 2026.
Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Eligibility Interest FormLink provided by the sponsor.
Individual participant dataSharing planned: No. The investigators do not have specific plans to share individual participant data in order to preserve the confidentiality of our participants. Any data that is shared would only be done so after executing a formal Data Use Agreement from Massachusetts General Hospital.

Related trials for Obsessive-Compulsive Disorder

Enrolling by invitation
Family Accommodation Reduction in Adult Obsessive Compulsive Disorder
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Not yet recruitingObservational study
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Treatment-refractory Obsessive-compulsive Disorder (trOCD)

Referral and contact

AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.

Joan Camprodon, MD, MPH, PhD principal investigator

Massachusetts General Hospital

1 site in 1 country: see every site and its status.

Questions about this trial

What is this clinical trial studying?

A study testing Active tDCS in people with Obsessive-Compulsive Disorder, run by Massachusetts General Hospital at 1 site in United States.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 10 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: finished, as of the sponsor's last update on 4 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

Are results available for this study?

Yes. Results are posted in the registry (first posted 4 Sep 2026). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.

How can a doctor refer a patient or contact the research team?

The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Difference in Frontomedial Theta Power (EEG) to the Conditioned Stimulus (CS+) Versus the Unconditioned Stimulus (CS-) Between tDCS Conditions During Extinction Recall (time frame: Extinction Recall Phase (Day 2)). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT05521074.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Sep 2026.