Disgust Reduction Through Evaluative Conditioning (DREC) and tDCS in Contamination-Based OCD

NCT05907369 | Unknown

• 2 other identifiers: 3/56765100/18979
• Study Type: interventional
• Target: 55
• Locations: 1 country
• Sites: 1

Brief Summary

Obsessive-compulsive disorder (OCD) is a debilitating health condition that is known by intrusive and unwanted thoughts and repetitive behavioral or mental acts. 2-3% of the population suffers from OCD in their lifetime. The most common OCD subtype is contamination. The Serotonin-selective reuptake inhibitors (SSRIs) and cognitive-behavioral therapy (CBT) based on exposure and response prevention (ERP) technique are the first-line treatments for OCD. The challenge is that nearly half do not respond to the first-line treatments or have residual symptoms after completion of treatments. However, the prevalence of the disorder, diversity of symptoms, inadequate response rate, and necessity of having long-lasting treatment effects make the treatments of OCD more challenging. It seems that abnormal, more intense disgust experience has a prominent role in developing and maintaining OCD symptoms, particularly the contamination subtype. Evaluative conditioning (EC), defined as transferring the value of the US to the CS through pairing them, is the most common way of establishing disgust responses. The present study aims to develop an emotion-based intervention technique using EC targeting disgust emotion in contamination-based OCD (C-OCD). The hypothesis is that EC training may modify disgust experiences. Disgust may be the culprit, at least in part, of cognitive deficiencies in OCD. The other hypothesis is whether disgust reduction-focused EC may improve cognitive function, such as attention bias and inhibitory control. The orbitofrontal cortex (OFC) is one of the brain areas engaged in disgust processing and is mostly hyperactive in OCD patients. Cathodal transcranial direct current stimulation (tDCS) over OFC is one of the helpful neuromodulation methods in treating OCD. We aim to see if this method may help to regulate disgust experiences in combination with EC. The participants may be referred by psychiatrists or psychotherapists or be self-referred due to online advertisements or paper flyers. They will be randomly assigned to one of for arms of the study for sham or active EC training along with sham or active tDCS, to which they are blind. The novelty of the present study is the application of EC training in the clinical OCD population in combination with a neuromodulation method.

Conditions

Obsessive-Compulsive Disorder

Keywords

Obsessive-Compulsive Disorder; Contamination symptoms; Disgust; Evaluative Conditioning; Transcranial Direct Current Stimulation; Orbitofrontal Cortex

Outcome Measures

Primary Outcomes (2)

• Disgust Feeling

  Effect of evaluative conditioning, cathodal tDCS over OFC, and both on changing disgust feeling intensity measured by disgust rating scale. The scale rates from 0 (not disgusting) to 10 (very disgusting). Lower scores show less disgust feeling.

  From pre- to post-assessment (2 weeks after baseline assessment) and from pre- to follow-up assessment (10 weeks after baseline assessment)

• Clinical Symptoms Severity of Contamination-Based OCD

  Change in Clinical symptoms of contamination-based OCD after evaluative conditioning, cathodal tDCS over OFC, and both, measured by Yale-Brown Obsessive-Compulsive scale. It is scored on a 5-point rating. The lower scores show less symptom severity.

  From pre- to post-assessment (2 weeks after baseline assessment) and from pre- to follow-up assessment (10 weeks after baseline assessment)

Secondary Outcomes (3)

• The power spectrum of brain waves based on quantitative electroencephalogram

  From pre- to post-assessment (2 weeks after baseline assessment) and from pre- to follow-up assessment (10 weeks after baseline assessment)

• Attentional bias

  From pre- to post-assessment (2 weeks after baseline assessment) and from pre- to follow-up assessment (10 weeks after baseline assessment)

• Inhibitory control

  From pre- to post-assessment (2 weeks after baseline assessment) and from pre- to follow-up assessment (10 weeks after baseline assessment)

Study Arms (4)

aEC/ stDCS

EXPERIMENTAL

Participants in this group receive active EC training but sham tDCS.

Other: Active EC training; Other: Sham tDCS

sEC/atDCS

ACTIVE COMPARATOR

Participants in this group receive active tDCS training but sham EC training.

Other: Sham EC training; Other: Active tDCS

aEC/atDCS

EXPERIMENTAL

Participants in this group receive both active EC training and active tDCS.

Other: Active EC training; Other: Active tDCS

sEC/stDCS

SHAM COMPARATOR

Participants in this group receive the sham EC training and also sham tDCS.

Other: Sham EC training; Other: Sham tDCS

Interventions

Active EC training OTHER

The active EC includes pairing contamination-related pictures (CSs) with pleasant pictures (USs). The EC training takes about 15 minutes and is administered for ten sessions (5 days a week) in 4 difficulty levels.

aEC/ stDCS; aEC/atDCS

Sham EC training OTHER

The active EC includes pairing contamination-related pictures (CSs) with neutral pictures (USs). The EC training takes about 15 minutes and is administered for ten sessions (5 days a week) in 4 difficulty levels, the same as active EC training.

sEC/atDCS; sEC/stDCS

Active tDCS OTHER

For the active tDCS, the cathode is placed over the left OFC and the anode over the right cerebellum. The brain stimulation is delivered with a 2mA current intensity for 20 minutes in 10 sessions (5 days a week).

aEC/atDCS; sEC/atDCS

Sham tDCS OTHER

For the sham tDCS, the cathode is placed over the left OFC and the anode over the right cerebellum, the same as active tDCS. The device is on for 20 minutes, but the current intensity is under the threshold of affecting cortical activity modulation. The participants receive the sham tDCS in 10 sessions (5 days a week).

aEC/ stDCS; sEC/stDCS

Eligibility Criteria

• Age: 18 Years - 55 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• 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

You may not qualify if:

• 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

Sponsors & Collaborators

• Ferdowsi University of Mashhad: lead

Study Sites (1)

Ferdowsi University of Mashhad

Mashhad, Razavi Khorasan Province, 91779 48974, Iran

RECRUITING

Related Publications (1)

• Al Mohaddesin FR, Moghimi A, Fadardi JS. Disgust-reduction evaluative conditioning (DREC) and brain stimulation in patients with contamination-based obsessive-compulsive disorder: a protocol for a randomized control trial. Trials. 2023 Nov 24;24(1):750. doi: 10.1186/s13063-023-07791-2.

  PMID: 38001473 DERIVED

MeSH Terms

Conditions

Obsessive-Compulsive Disorder

Condition Hierarchy (Ancestors)

Anxiety Disorders; Mental Disorders

Study Officials

• Ali Moghimi, PhD

  Ferdowsi University of Mashhad

  STUDY DIRECTOR

Central Study Contacts

Ali Moghimi, PhD

CONTACT

0098 09153176390; moghimi@um.ac.ir

Faezeh Raeisalmohaddesin, MsC

CONTACT

0098 09151232724; fh.raeesi@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Masking Details: Participants are blind to which of the interventions is active or a sham. Interventional sessions look the same for all participants regarding duration and activities (including doing a computerized EC task and receiving tDCS).
• Purpose: TREATMENT
• Intervention Model: FACTORIAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Model Details: The two interventions include evaluative conditioning (EC) training and cathodal tDCS over OFC. Each is present in two forms: active and sham. So, there are four interventional conditions, including sham EC-sham tDCS, active EC- sham tDCS, sham EC-active tDCS, and active EC-active tDCS.

Study Record Dates

• First Submitted: May 15, 2023
• First Posted: June 18, 2023
• Study Start: January 20, 2023
• Primary Completion: December 30, 2023
• Study Completion: March 29, 2024
• Last Updated: February 28, 2024

Record last verified: 2023-09

Data Sharing

• IPD Sharing: Will not share

Locations

IR (1)