Modulating Context Generalization Through Transcranial Direct Current Stimulation

Study Overview
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Brief Summary
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Behavioral adaptation is particularly relevant to anxiety and related disorders, where exposure-based therapies rely on such adaptation as part of behavior therapy.. However, while initial fear reactions generalize easily across contexts, subsequent adaption of behavior through learning is context-specific. The primary goal of this study is to investigate whether transcranial direct current stimulation (tDCS) can be used to acutely impact generalization of subsequent learning across contexts in an experimental paradigm. As part of this study, participants will complete a clinical interview and questionnaires, as well as a computer task asking them to make choices between stimuli on the screen and during which they may or may not receive tDCS.

Official Title
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Modulating Context Generalization Through Transcranial Direct Current Stimulation

Conditions
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Anxiety and Fear

Intervention / Treatment
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* Device: active tDCS
* Device: sham tDCS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Primary diagnosis of an anxiety or related disorder, (defined as panic disorder, social anxiety disorder, generalized anxiety disorder, obsessive-compulsive disorder, and/or post-traumatic stress disorder); aged 18-55; ability to speak, read, write, and understand English sufficiently well to complete study procedures and provide informed consent; Stable psychiatric medication use for at least 6 weeks. Exclusion Criteria: Lifetime history of psychotic symptoms or bipolar disorder, Current substance use disorder; Acute suicidality or homicidality, Significant neurological disorder, Any problems that would interfere with study participation, significant or unstable medical disorders and tDCS-related contraindications (e.g., implanted metallic substances, pregnancy, holes in the skull, skin abnormalities under stimulation sites).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 55 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Active tDCS<br> | Device: active tDCS<br>* 15 minutes of active (2mA) high definition tDCS will be applied to the participant's skull. The anodal electrode will be placed over 10-20 EEG coordinate AF7 and cathodal electrode over coordinate Fz.<br>|
| Sham Comparator: Sham tDCS<br> | Device: sham tDCS<br>* 15 minutes of sham high definition tDCS will be applied to the participant's skull. The anodal electrode will be placed over 10-20 EEG coordinate AF7 and cathodal electrode over coordinate Fz.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relative frequency of selection of task-specific stimuli |  | 1 hour (measurement occurs 1 time only) |