tDCS-Augmented Exposure Therapy for Pathological Fear

The University of Texas System (UT)

Status: Completed

Conditions: Specific Phobias

Treatments: Behavioral: In vivo exposure therapy; Device: Transcranial Direct Current Stimulation (tDCS)

Study type: Interventional

Funder types: Other

Identifiers

NCT03095482

2016-02-0024

Details and patient eligibility

About

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.

Full 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.

Enrollment: 49 patients

Sex: All

Ages: 18 to 65 years old

Volunteers: Accepts Healthy Volunteers

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.

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Quadruple Blind

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49 participants in 2 patient groups

Active tDCS + In Vivo Exposure

Active Comparator group

Description:

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.

Treatment:

Device: Transcranial Direct Current Stimulation (tDCS)

Behavioral: In vivo exposure therapy

sham tDCS + In Vivo Exposure

Sham Comparator group

Description:

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.

Treatment:

Behavioral: In vivo exposure therapy