Aggression, Antisocial Behavior
Conditions
Keywords
antisocial behavior, aggression, transcranial direct current stimulation, dorsolateral prefrontal cortex, associated risk factors
Brief summary
This study investigates the effect of upregulating prefrontal cortex activity on antisocial and aggressive behavior and risk factors for such behavior. In the double-blind, randomized controlled trial, participants will undergo anodal transcranial direct current stimulation bilaterally to the dorsolateral prefrontal cortex or a sham stimulation. During and after stimulation, they will complete survey and laboratory measures assessing antisocial and aggressive behavior and risk factors for antisocial and aggressive behavior. Heart rate and skin conductance will also be measured.
Interventions
DEVICETranscranial direct current stimulation
DEVICESham transcranial direct current stimulation
Sponsors
University of Pennsylvania
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
* Above 18 years of age * Able to understand the nature of the study and give informed consent
Exclusion criteria
* History of or active neurologic, cardiovascular, or psychiatric disease * Currently consuming anti-convulsant, anti-psychotic, or sedative/hypnotic medications * Currently consuming anti-depressants * History of seizures * Metallic implants on the scalp * Participation in other transcranial magnetic stimulation (TMS) or tDCS experiments on the same day * History of adverse reactions to tDCS
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Number of Pins Inserted Into a Virtual Voodoo Doll at 24 Hours | On average, 24 hours after the tDCS or sham session | The number of pins (between 0 and 51) that participants decide to insert into a picture of a voodoo doll on a computer that represents either a romantic partner or close friend will be recorded on average 24 hours after receiving tDCS or sham stimulation. |
| Change in Antisocial Behavior Inclinations at 24 Hours | Baseline (an average of 15 minutes before receiving tDCS or sham) and on average, 24 hours following stimulation or sham | This will be assessed using hypothetical scenarios in which someone commits a criminal or antisocial act. The two brief scenarios describe a physical assault and a sexual assault. Participants will respond to the likelihood that they would commit the act in the scenario according to a 10-point Likert scale. Responses were measured on a scale ranging from zero (no chance at all) to ten (100 percent chance). Scores for both scenarios were summed to obtain an overall measure of intentions to commit aggression. Possible scores range from 0 to 20. A higher value indicates a greater inclination to engage in the antisocial act. |
Countries
United States
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Anodal Stimulation Participants in the active stimulation group will undergo anodal bilateral transcranial direct current stimulation (tDCS) of the dorsolateral prefrontal cortex. tDCS will be delivered by a battery-driven, constant-current stimulator connected to three saline-soaked surface sponge electrodes. Two anodal electrodes (25cm2) will be placed over the dorsolateral prefrontal cortex bilaterally and one cathodal electrode (35cm2) will be placed at the back of the neck. Scalp electrodes will be positioned over the F3 and F4 according to the 10-20 EEG international system. A current of 1mA will be applied for 20 minutes and the current will be ramped up and down at the beginning and end of the stimulation period.
Transcranial direct current stimulation | 39 |
| Sham Stimulation The sham transcranial direct current stimulation condition will involve the same placement of the electrodes, current intensity, and ramp time as the real tDCS condition, but stimulation will only last for 30 seconds.
Sham transcranial direct current stimulation | 42 |
| Total | 81 |
Baseline characteristics
| Characteristic | Anodal Stimulation | Sham Stimulation | Total |
|---|---|---|---|
| Age, Continuous | 20.26 years STANDARD_DEVIATION 4.13 | 20.17 years STANDARD_DEVIATION 2.36 | 20.21 years STANDARD_DEVIATION 3.31 |
| Race/Ethnicity, Customized Caucasian | 17 Participants | 19 Participants | 36 Participants |
| Race/Ethnicity, Customized Non-Caucasian | 22 Participants | 23 Participants | 45 Participants |
| Region of Enrollment United States | 39 Participants | 42 Participants | 81 Participants |
| Sex: Female, Male Female | 24 Participants | 21 Participants | 45 Participants |
| Sex: Female, Male Male | 15 Participants | 21 Participants | 36 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk |
|---|---|---|
| deaths Total, all-cause mortality | 0 / 39 | 0 / 42 |
| other Total, other adverse events | 39 / 39 | 39 / 42 |
| serious Total, serious adverse events | 0 / 39 | 0 / 42 |
Outcome results
Primary
Change in Antisocial Behavior Inclinations at 24 Hours
This will be assessed using hypothetical scenarios in which someone commits a criminal or antisocial act. The two brief scenarios describe a physical assault and a sexual assault. Participants will respond to the likelihood that they would commit the act in the scenario according to a 10-point Likert scale. Responses were measured on a scale ranging from zero (no chance at all) to ten (100 percent chance). Scores for both scenarios were summed to obtain an overall measure of intentions to commit aggression. Possible scores range from 0 to 20. A higher value indicates a greater inclination to engage in the antisocial act.
Time frame: Baseline (an average of 15 minutes before receiving tDCS or sham) and on average, 24 hours following stimulation or sham
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal Stimulation | Change in Antisocial Behavior Inclinations at 24 Hours | 1.41 score on a scale | Standard Error 0.33 |
| Sham Stimulation | Change in Antisocial Behavior Inclinations at 24 Hours | 3.05 score on a scale | Standard Error 0.68 |
Primary
Number of Pins Inserted Into a Virtual Voodoo Doll at 24 Hours
The number of pins (between 0 and 51) that participants decide to insert into a picture of a voodoo doll on a computer that represents either a romantic partner or close friend will be recorded on average 24 hours after receiving tDCS or sham stimulation.
Time frame: On average, 24 hours after the tDCS or sham session
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| Anodal Stimulation | Number of Pins Inserted Into a Virtual Voodoo Doll at 24 Hours | 5.31 pins | Standard Error 1.9 |
| Sham Stimulation | Number of Pins Inserted Into a Virtual Voodoo Doll at 24 Hours | 2.62 pins | Standard Error 1.32 |