tDCS-Augmented Exposure Therapy for Pathological Fear

Not Applicable

Completed

• Conditions: Specific Phobias
• Interventions: Device: Transcranial Direct Current Stimulation (tDCS); Behavioral: In vivo exposure therapy

• Registration Number: NCT03095482
• Lead Sponsor: University of Texas at Austin

Brief Summary

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.

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 Timeline

• Study Start: 2017-01-01
• Study First Submitted: 2017-03-20
• Study First Submitted QC: 2017-03-23
• Study First Posted: 2017-03-29
• Primary Completion: 2018-09-06
• Study Completion: 2018-09-06
• Status Verified: 2020-12
• Last Update Submitted: 2020-12-04
• Last Update Posted: 2020-12-08

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 49

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 & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Active tDCS + In Vivo Exposure	Transcranial Direct Current Stimulation (tDCS)	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.
Active tDCS + In Vivo Exposure	In vivo exposure therapy	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.
sham tDCS + In Vivo Exposure	In vivo exposure therapy	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.

Primary Outcome Measures

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

Secondary Outcome Measures

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

Trial Locations

Locations (1)

Laboratory for the Study of Anxiety Disorders; 🇺🇸 Austin, Texas, United States