Transcranial Direct Current Stimulation and Antisocial Behavior

Study Overview
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Brief Summary
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The main objective of this study is to investigate the causal relationship between prefrontal cortex activity and antisocial behavior, as well as risk factors for antisocial behavior. Specifically, this study tests the hypothesis that upregulating activity in the prefrontal cortex through a non-invasive form of brain stimulation, transcranial direct current stimulation (tDCS) will reduce antisocial and aggressive behavior. The effects of 3 days of anodal stimulation over the prefrontal cortex are assessed.

Official Title
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The Effect of Transcranial Direct Current Stimulation of the Prefrontal Cortex on Antisocial Behavior

Conditions
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Aggression

Intervention / Treatment
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* Device: Transcranial direct current stimulation
* Device: Sham transcranial direct current stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Above 18 (with parental consent) or above 21 (without parental consent) Able to understand the nature of the study and give informed consent Exclusion Criteria: History of or active neurologic, cardiovascular, or psychiatric disease including anxiety disorders (e.g., PTSD, panic attacks, obsessive-compulsive disorder) and mood disorders (e.g., depression) Currently consuming anti-convulsant, anti-psychotic, or sedative/hypnotic medications Currently consuming anti-depressants History of seizures Metallic implants on scalp Participated in any other non-invasive brain stimulation study in the same day Ever had an adverse reaction to tDCS

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

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: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Anodal stimulation<br>Participants in the active stimulation group will undergo anodal transcranial direct current stimulation (tDCS). tDCS will be delivered by a battery-driven, constant-current stimulator connected to two saline-soaked surface sponge electrodes. An anodal electrode (25cm2) will be placed over the ventromedial prefrontal cortex and one cathodal electrode (35cm2) will be placed over the occipital cortex. Scalp electrodes will be positioned according to the 10-20 EEG international system. A current of 2mA will be applied for 20 minutes and the current will be ramped up and down over 30 seconds at the beginning and end of the stimulation period. | Device: Transcranial direct current stimulation<br>* Non-invasive stimulation will be conducted using a tDCS device (StarStim, Neuroelectrics, Spain).<br>|
| Sham Comparator: Sham stimulation<br>The sham tDCS condition will involve the same placement of the electrodes, current intensity, and ramp-up/down time as the active tDCS condition, but stimulation will only last for 30 seconds. | Device: Sham transcranial direct current stimulation<br>* The same device will be used as in the active stimulation group, but stimulation will be terminated after 30 seconds.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Points in the Point Subtraction Aggression Paradigm after stimulation | The number of points earned on the lab task will be assessed. | Within 1 hour after the third consecutive active tDCS or sham session | 
| Antisocial behavior inclinations after stimulation | This will be assessed using 5 hypothetical scenarios in which someone commits a criminal or antisocial act. Participants will respond to the likelihood that they would commit the act in the scenario according to a 10-point Likert scale. Responses are measured on a scale ranging from zero (no chance at all) to 10 (100% chance). A higher value reflects a greater intention to engage in the antisocial act. | Within 1 hour after the third consecutive active tDCS or sham session | 
| Moral judgment ratings after stimulation | This will be assessed using 5 hypothetical scenarios in which someone commits a criminal or antisocial act. Participants will rate the moral wrongfulness of the act in the scenario on a scale from 0 (not at all) to 10 (very). A higher score reflects a greater perception of moral wrongfulness regarding the antisocial act. | Within 1 hour after the third consecutive active tDCS or sham session | 
| Delay discounting rates after stimulation | Participants' responses to 5 questions indicating if they would prefer a smaller reward today or a larger reward in the specified number of days will be assessed. The delay discount rates (k) of monetary rewards will be calculated based on the responses to the 5 trials. | Within 1 hour after the third consecutive active tDCS or sham session | 
| Helping behavior after stimulation | This will be assessed based on the number of easy and hard puzzles participants choose to assign to another participant in the study. | Within 1 hour after the third consecutive active tDCS or sham session | 
| Antisocial behavior after stimulation | This will be assessed based on the participants' accurate reporting of the number of problems correctly solved in a task. | Within 1 hour after the third consecutive active tDCS or sham session | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with adverse events | The number of participants reporting the experience of sensations resulting from tDCS will be recorded. | Within 1 hour after each of the 20-minute active tDCS or sham sessions | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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transcranial direct curren stimulation, antisocial behavior