Reducing disgust in contamination-based OCD using conditioning and brain stimulation

Disgust Reduction Through Evaluative Conditioning and tDCS in Patients With Contamination-Based OCD

NA · Ferdowsi University of Mashhad · NCT05907369

This study is testing a new way to help people with contamination-based OCD by using special training and brain stimulation to reduce their feelings of disgust.

Quick facts

PhaseNA
Study typeInterventional
Enrollment55 (estimated)
Ages18 Years to 55 Years
SexAll
SponsorFerdowsi University of Mashhad (other)
Locations1 site (Mashhad, Khorassan Razavi)
Trial IDNCT05907369 on ClinicalTrials.gov

What this trial studies

This clinical trial aims to address contamination-based obsessive-compulsive disorder (OCD) by utilizing evaluative conditioning (EC) to reduce disgust responses associated with contamination stimuli. Participants will undergo training that pairs disgust-eliciting images with positive images to alter their emotional responses. Additionally, transcranial direct current stimulation (tDCS) will be applied to enhance the effects of the EC training. The study seeks to improve treatment outcomes for individuals who have not responded adequately to traditional therapies.

Who should consider this trial

Good fit: Ideal candidates for this study are individuals diagnosed with contamination-based OCD who have stable medication and can engage in computerized tasks.

Not a fit: Patients with severe physical illnesses, other severe mental disorders, or those with a history of epilepsy or neurological disorders may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could provide a novel and effective treatment option for patients suffering from contamination-based OCD.

How similar studies have performed: While the approach of using evaluative conditioning in OCD is promising, it is still relatively novel and has not been extensively tested in this specific context.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* The Diagnostic criteria of OCD in the Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5-TR) with the symptoms of contamination subtype
* Able to read, write and do computerized tasks
* Stable medication for at least the last three months
* Filling out the written consent

Exclusion Criteria:

* Severe physical illness
* Severe other mental disorders
* Alcohol and drug dependence
* A history of epilepsy or seizure
* Have metal or electronic implants in the head or use a cardiac pacemaker
* History of head trauma or neurological disorders
* Women who are pregnant or may be pregnant
* Unable to complete questionnaires, computerized tasks, or informed consent

Where this trial is running

Mashhad, Khorassan Razavi

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.

View on ClinicalTrials.gov →

Conditions: Obsessive-Compulsive Disorder, Contamination symptoms, Disgust, Evaluative Conditioning, Transcranial Direct Current Stimulation, Orbitofrontal Cortex

Last reviewed 2026-05-15 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.