tDCS targeting the Ventromedial Prefrontal Cortex reduces reactive aggression and modulates electrophysiological responses: A HD-tDCS/EEG randomized controlled trial in a forensic population.

Abstract

Studies have shown that impairments in the ventromedial prefrontal cortex (vmPFC) in forensic patients who also abuse cocaine and alcohol play a crucial role in are found not to be effective. A promising intervention is to modulate the vmPFC by transcranial Direct Current Stimulation (tDCS). This study aimed to investigate high definition (HD)-tDCS as an intervention to increase empathic abilities in order to reduce violent behavior in forensic patients. In addition, using electroencephalography (EEG), we examined the effects of tDCS on the event-related potentials P3 and LPP in reaction to situations that depict victims of aggression (i.e. empathy). Fifty male forensic substance use patients (25 in the active and 25 in the sham condition) were tested in a double-blind placebo-controlled study. The patients received HD-tDCS two times a day for 20 min for five consecutive days. Before and after the intervention, the patients completed self-reports, performed the Point Subtraction Aggression Paradigm (PSAP), and EEG was recorded while patients performed an empathy task. Results showed a significant decrease in aggressive responses on the PSAP and a decrease in self-reported reactive aggression in the active tDCS group. Additionally, we found an increase in LPP amplitude after tDCS intervention in the active tDCS group compared to the sham group. No effects on the P3 were found. Current findings are the first to find effects of tDCS modulating aggression and electrophysiological responses in forensic patients, thereby showing the potential for tDCS as a intervention in forensic mental healthcare.

Neurobiological Responses towards Stimuli Depicting Aggressive Interactions in Delinquent Young Adults and Controls: No Relation to Reactive and Proactive Aggression

“…Considering the electrophysiological results, we only found a significant effect of condition for the LPP; however, no significant differences between the groups were found on the P3, LPP and alpha ERD/ mu suppression. The fact that we found a condition effect for only the LPP, and not for the other electrophysiological measures is not in line with prior work using the same task [75,87]. Moreover, the fact that no differences between the groups were found was not in line with our expectations, since earlier studies did find attenuated P3 and LPP amplitudes in affective picture viewing to be related to antisocial personality and delinquency [75,88,89].…”

“…Third, the validity of the task to induce emotional arousal in aggression versus neutral conditions was questionable in the current study. However, previous studies using the same picture task did find support for its validity [75,87]. It may however be that the passive viewing task is less suitable to induce changes, in particular, neurobiological indices such as HR and RSA.…”