Neuromodulation as an intervention to improve empathic abilities and reduce violent behavior in forensic offenders

Rationale:

Substance abuse problems have an important relationship with criminal behavior. These problems occur in 50-75% of the offenders, and cost the community about 600 milliard due to costs of crime, work-related problems and especially (mental) healthcare. Problems that substance abuse patients cause are an enormous burden to the community (financial and safety). Previous research has found that substance abuse, especially alcohol and cocaine, are related to (violent) criminal behavior. Money invested in treatment may lead to a large reduction in the costs associated with substance abuse.

Nevertheless, current interventions seem insufficient in treatment of substance abuse in
forensic mental health care and are not sufficient enough to reduce violence risk, 66% of the
patients reoffend. This could be due to the fact that problem is caused by a complex medical-
psychiatric disorder, occurring within a poor motivated population, in which the prolonged
usage of substances has led to functional and structural changes in the brain.
Recent studies show that changes in the brain areas related to less empathic abilities (i.e.
the Ventromedial Prefrontal Cortex (vmPFC) plays an important role in violent
behavior in abusers of alcohol and cocaine.

According to the recent models violent behavior is supposed to be inhibited by empathy. Individuals with less empathic abilities may be less susceptible and
motivated to inhibit violent behavior, which causes a higher risk of violence.
Recent neuroscientific research shows that modulating (stimulation or inhibition) of certain brain
areas, such as the neurostimulation technique Transcranial Direct Current Stimulation (tDCS), could be a promising new intervention for substance abuse and to reduce violent
behavior.


Objective: The aim of this study is to investigate the effectiveness of tDCS in increasing
empathy and reducing violent behavior in offenders with substance abuse problems. Through stimulation (and/or inhibiting) certain areas of the brain, tDCS causes a change in the function of the brain, due to an increase in susceptibility to generate and facilitate brain
related electrical impulses. This susceptibility is achieved through repeatedly offer brain stimulation and this causes ‘learning’ of the brain cells. Functions of the brain damaged and changed by the substance abuse will be recovered.


Study design: The design will be a double-blind, placebo-controlled study.


Study population: A total sample of 50 male forensic addicted patients (25 experimental + 25 sham stimulation) between the age of 18-60 years will be tested in a double-blind placebo-controlled study.
Intervention (if applicable): 25 patients will receive the experimental condition + treatment as usual (TAU) and the other 25 patients will receive a sham condition (placebo) + TAU.


Main study parameters/endpoints: The study investigates the effectiveness of tDCS to change the learning process of the brain cells through electrical stimulation and with that to increase empathic abilities and reduce violence risk in offenders with substance abuse problems. To test the effect of the intervention on the level of empathy, patients will perform a passive viewing task in which they see victims of aggression and rate the degree of empathy they feel for each of the pictures after the passive viewing part of the task.

To test the effect of the intervention on aggression, the Point Subtraction Aggression Paradigm (PSAP) will be used. As a standard for effectiveness of the reduction of violent behavior before and after the tDCS intervention next to the aggression task (PSAP-task) the results of the K-items of the HKT-R risk assessment tool before and after the intervention will be compared.
To measure the degree of brain changes in empathy caused by the intervention, electro- encephalography (EEG) will be used. The expectation is that patients who receive tDCS intervention will show higher amplitude in EEG towards the pictures of the victims after the intervention and compared patients who have received the sham-condition.

The intervention with Transcranial Direct Current Stimulation (tDCS) on the Ventromedial Prefrontal Cortex (vmPFC) in comparison with the treatment as usual will improve empathic abilities and reduce violent behavior in forensic substance use offenders.

Measurements:

-Empathy will be measured with the 'Passive Viewing Empathy Task'

-Violent behavior will be measured with the 'Point Substraction Aggression Paradigm'.

-Electrophysiological changes will be measured with Electroencephalography (EEG).



Questionnaires:

-Psychopathic traits will be assessed using the Dutch short version of the SRP-SF. (Self Report Psychopathy Scale ;SRP-SF)

- Reactive and Proactive Aggression will be measured using the Dutch version of the Reactive and Proactive AggressionQuestionnaire (RPQ).

Empathy is measured Interpersonal Reactivity Index (IRI) [81]

Empathy will be measured using the Dutch IRI

 Toronto Alexithymia Scale (TAS-20) [82] Aggression will be measured using the Dutch RPQ.

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tDCS as intervention for violence risk

 Behavioral Impulsivity Scale (BISS11) [89] Impulsivity will be measured using the Dutch BISS11

 Risky, Impulsive, and Self-Destructive Behavior Questionnaire (RISQ) [83] Risky and Impulsive behavior will be measured using the Dutch version of the RISQ

 Alcohol Use Disorders Identification Test (AUDIT) [79] Alcohol use will be measured using the Dutch version of the AUDIT

 Drug Use Disorder Identification Test (DUDIT) [84] Drug use will be measured using the Dutch version of the DUDIT

 Obsessive Compulsive Drug Use Scale (OC-DUS-versie Cocaïne) [85] Drug craving will be measured using the Dutch version of the OC-DUS.

 Obsessive Compulsive Drinking Scale (OCDS) [86]

Alcohol craving will be measured using the Dutch version of the OCDS

tDCS will be administered with a CE-certified neurostimulator (StarStim-8, NeuroElectrics) following the protocol used by Geniole, MacDonell & McCormick (2016). The device will be preprogrammed for stimulation with 2mA during 20 minutes (experimental conditions), or with 2 mA during 30 seconds (sham condition). It is possible to program the device for each participant, ensuring that the participant and experimenter are blinded for experimental condition.
The treatment under study is a tDCS intervention. The experimental treatment is a 20 minutes tDCS session, two times a day for 5 days (10 sessions per participant). HD-tDCS stimulation will be applied over the VMPFC.

Sham condition is the same as the experimental condition with the exception that there will only be a ramp up of the electrical stimulation to mimic the sensation of the stimulation.