Specific Phobias
Conditions
Keywords
Arachnophobia (fear of spiders), Ophidophobia (fear of snakes), Germaphobia (fear of germs, dirtiness, and contamination)
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.
Interventions
DEVICETranscranial Direct Current Stimulation (tDCS)
Participants will receive 20 minutes of either active or sham tDCS prior to in vivo exposure to feared targets.
BEHAVIORALIn vivo exposure therapy
Participants will receive 30 minutes of in vivo exposure to feared targets following either active or sham tDCS
Sponsors
University of Texas at Austin
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Masking description
Participants, treatment administrators, and outcome assessors will be blind to tDCS condition.
Intervention model description
Participants will be randomly assigned to receive either (a) excitatory tDCS of the medial prefrontal cortex and inhibitory tDCS of right dorsolateral prefrontal cortex, or (b) sham tDCS
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
Yes
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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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. |
| 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. |
| 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 |
| 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. |
| 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. |
| 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 |
Countries
United States
Outcome results
None listed