tDCS-Augmented Exposure Therapy for Pathological Fear

This double-blind randomized controlled clinical trial aims to test whether transcranial direct current stimulation (tDCS) can be used to modulate fear extinction learning during exposure therapy for pathological fear, including fear of spiders, snakes, or germs / contamination. Participation takes place over three laboratory visits, including (1) a pre-treatment visit, (2) a treatment and post-treatment visit, and (3) a 1 month follow-up visit. During treatment, participants will receive either 20 minutes of active or sham tDCS, followed by 30 minutes of in vivo exposure therapy.

Study Overview

• Status: Completed
• Conditions: Specific Phobias
• Intervention / Treatment: Device: Transcranial Direct Current Stimulation (tDCS); Behavioral: In vivo exposure therapy

Detailed Description

In a trans-diagnostic sample with marked pathological fear and behavioral avoidance, this study aims to: (1) evaluate whether excitatory tDCS of the mPFC and inhibitory tDCS of right dlPFC enhances exposure therapy relative to sham tDCS; (2) determine whether tDCS effects are moderated by baseline negative prognostic indicators; and (3) determine whether tDCS effects are mediated by pre-post changes in vigilance to threat, in-session fear reduction, and contextual memory for the exposure context. If successful, the project may discover a potentially effective exposure therapy augmentation, and may enhance knowledge of the behavioral, cognitive, affective, and neurobiological factors that moderate and mediate acute treatment response and maintenance of treatment gains. This knowledge may inform treatment development efforts for more debilitating forms of pathological fear.

• Study Type: Interventional
• Enrollment (Actual): 49
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Texas
    • Austin, Texas, United States, 78712
      • Laboratory for the Study of Anxiety Disorders

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 65 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

1. Age 18-65.
2. Fluent in English.
3. A score on at least 1 fear domain-specific prescreen measure > 2 SDs above the subject pool prescreen mean. These measures include (a) FSQ, and (b) OCI-R.
4. Peak fear ≥ 50 on BATs 1 and 2.

Exclusion Criteria:

1. Currently receiving treatment for the primary fear domain (based on clinical interview).
2. Unstable dose of psychotropic medications within 6 weeks prior to baseline assessment (based on the DMQ; see measures).
3. Medical condition that would contraindicate participation in treatment or assessment activities (e.g., cardiovascular problems; based on the DMQ; see measures).
4. Pregnancy (based on the DMQ; see measures).
5. Current major depressive disorder (based on MINI; see measures).
6. Current, or history of bipolar disorder (based on MINI; see measures).
7. Current, or history of psychotic symptoms (based on MINI; see measures).
8. Serious suicidal risk, as determined by self-report (C-SSRS, BDI-II) and clinical interview (MINI; see measures).
9. Active neurological conditions, including seizures, stroke, unexplained loss of consciousness or concussion (based on DMQ and tDCS Safety Screening Form; see measures)
10. Contraindications for tDCS: Metal in the head or implanted brain medical devices.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Active tDCS + In Vivo Exposure; Participants assigned to this condition will receive excitatory transcranial direct current stimulation (tDCS) of the left medial prefrontal cortex (lmPFC) and inhibitory tDCS of right dorsolateral prefrontal cortex (rdlPFC). tDCS will be administered for 20 minutes at 1.7 mA, followed by 30 minutes of in vivo exposure therapy.	Device: Transcranial Direct Current Stimulation (tDCS); Participants will receive 20 minutes of either active or sham tDCS prior to in vivo exposure to feared targets.; Behavioral: In vivo exposure therapy; Participants will receive 30 minutes of in vivo exposure to feared targets following either active or sham tDCS
Sham Comparator: sham tDCS + In Vivo Exposure; Participants assigned to this condition will receive sham transcranial direct current stimulation (tDCS), which will consist of 30 seconds of stimulation at the beginning and end of tDCS administration. Electrode positioning will be counterbalanced across participants (i.e., either mPFC+ or mPFC-, with same electrode positioning as the active comparators). Sham tDCS will be administered for 20 minutes, followed by 30 minutes of in vivo exposure therapy.	Behavioral: In vivo exposure therapy; Participants will receive 30 minutes of in vivo exposure to feared targets following either active or sham tDCS

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in peak fear during two behavioral approach tasks across time-points.	Subjective units of distress from 0 = no fear, to 100 = extreme fear	Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)
Change in approach level during two behavioral approach tasks across time points.	Highest difficulty level achieved from 0 = least challenging to 10 = most challenging.	Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in arachnophobia symptom severity across time-points	Total score on the Fear of Spiders Questionnaire	Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)
Change in ophidophobia symptom severity across time-points	Total score on the Fear of Snakes Questionnaire	Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)
Change in germaphobia / contamination fear symptom severity across time points.	Total score on the Obsessive Compulsive Inventory - Revised.	Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)
Threat vigilance task	Computer-based task that assesses attention biases towards and away from threatening images.	Before and after tDCS administration (1 week after baseline)
Visuospatial working memory task	Delayed match to sample task assessing recognition of 4 x 4 arrays of colored blocks, after a brief delay.	Before and after tDCS administration (1 week after baseline)
Incidental contextual memory task	Assessment of incidental memory for a 4 x 4 array of line drawings from the Test of Memory Malingering, presented in the treatment context only during in vivo exposure.	Stimulus presented during in vivo exposure (1 week after baseline), and memory assessed at follow-up (1 month after treatment)

Collaborators and Investigators

• Sponsor: University of Texas at Austin
• Investigators: Principal Investigator: Adam R. Cobb, Ph.D., The University of Texas at Austin; Study Director: Michael J. Telch, PhD, The University of Texas at Austin

Publications and helpful links

Helpful Links

• Website for the Laboratory for the Study of Anxiety Disorders

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2017
• Primary Completion (Actual): September 6, 2018
• Study Completion (Actual): September 6, 2018

Study Registration Dates

• First Submitted: March 20, 2017
• First Submitted That Met QC Criteria: March 23, 2017
• First Posted (Actual): March 29, 2017

Study Record Updates

• Last Update Posted (Actual): December 8, 2020
• Last Update Submitted That Met QC Criteria: December 4, 2020
• Last Verified: December 1, 2020

More Information

Terms related to this study

• Keywords: Arachnophobia (fear of spiders); Ophidophobia (fear of snakes); Germaphobia (fear of germs, dirtiness, and contamination)
• Other Study ID Numbers: 2016-02-0024

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: No