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Completed

NCT Number: NCT03095482

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.

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Key information

Conditions

Specific Phobias Arachnophobia Mysophobia Phobia, Specific Zoophobia

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Laboratory for the Study of Anxiety Disorders

Austin, Texas, 78712, United States

About this study

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.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18-65.
  • Fluent in English.
  • 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.
  • Peak fear ≥ 50 on BATs 1 and 2.

Exclusion criteria

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

Treatment and study plan

Transcranial direct current stimulation (tDCS)

Device

Participants will receive 20 minutes of either active or sham tDCS prior to in vivo exposure to feared targets.

In vivo exposure therapy

Behavioral

Participants will receive 30 minutes of in vivo exposure to feared targets following either active or sham tDCS

Primary outcomes

  1. Change in peak fear during two behavioral approach tasks across time-points.

    Time frame: 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

  2. Change in approach level during two behavioral approach tasks across time points.

    Time frame: 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 outcomes

  1. Change in arachnophobia symptom severity across time-points

    Time frame: Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)

    Total score on the Fear of Spiders Questionnaire

  2. Change in ophidophobia symptom severity across time-points

    Time frame: Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)

    Total score on the Fear of Snakes Questionnaire

  3. Change in germaphobia / contamination fear symptom severity across time points.

    Time frame: Pre-treatment (baseline), post-treatment (1 week later), and follow-up (1 month after treatment)

    Total score on the Obsessive Compulsive Inventory - Revised.

  4. Threat vigilance task

    Time frame: Before and after tDCS administration (1 week after baseline)

    Computer-based task that assesses attention biases towards and away from threatening images.

  5. Visuospatial working memory task

    Time frame: 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.

  6. Incidental contextual memory task

    Time frame: 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.

Sponsors and collaborators

Lead sponsor

University of Texas at Austin

Other

Registry information

Important dates

Study start
2017
Primary completion
2018
Study completion
2018
First posted
Mar 29, 2017
Registry last updated
Dec 8, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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