Aggression
Conditions
Keywords
transcranial direct curren stimulation, antisocial behavior
Brief summary
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.
Interventions
DEVICETranscranial direct current stimulation
Non-invasive stimulation will be conducted using a tDCS device (StarStim, Neuroelectrics, Spain).
DEVICESham transcranial direct current stimulation
The same device will be used as in the active stimulation group, but stimulation will be terminated after 30 seconds.
Sponsors
Nanyang Technological University
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 (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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Moral judgment ratings after stimulation | Within 1 hour after the third consecutive active tDCS or sham session | 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. |
| Points in the Point Subtraction Aggression Paradigm after stimulation | Within 1 hour after the third consecutive active tDCS or sham session | The number of points earned on the lab task will be assessed. |
| Antisocial behavior inclinations after stimulation | Within 1 hour after the third consecutive active tDCS or sham session | 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. |
| Antisocial behavior after stimulation | Within 1 hour after the third consecutive active tDCS or sham session | This will be assessed based on the participants' accurate reporting of the number of problems correctly solved in a task. |
| Delay discounting rates after stimulation | Within 1 hour after the third consecutive active tDCS or sham session | 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. |
| Helping behavior after stimulation | Within 1 hour after the third consecutive active tDCS or sham session | This will be assessed based on the number of easy and hard puzzles participants choose to assign to another participant in the study. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Number of participants with adverse events | Within 1 hour after each of the 20-minute active tDCS or sham sessions | The number of participants reporting the experience of sensations resulting from tDCS will be recorded. |
Countries
Singapore
Outcome results
None listed