Polyvagal theory proposed that an autonomous nervous system imbalance might be characteristic of violent individuals, especially reduced parasympathetic or vagal tone. Accordingly, some studies concluded that when intimate partner violence (IPV) perpetrators deal with acute stress, they tend to present a sympathetic predominance over the parasympathetic nervous system once the stress has ended. However, less is known about cognitive mechanisms that explain this phenomenon. In fact, this functioning might be explained by inner speech and/or angry thoughts (anger rumination) in reactive aggressors. Nonetheless, there is a gap in the scientific literature assessing whether this psychophysiological functioning in IPV perpetrators is explained by anger rumination. For this reason, the first aim of this study was to assess the cardiorespiratory (heart rate (HR), pre-ejection period (PEP), and respiratory sinus arrhythmia (RSA)) and electrodermal (skin conductance level (SCL)) changes, as well as the anger state, when coping with an acute laboratory stressor, comparing a group of reactive IPV perpetrators (n = 47) and a group of non-violent men (n = 36). The second aim was two-fold. After checking whether the groups differed on their anger rumination and manifestation of aggression (reactive and/or proactive) scores, we studied whether these variables explained psychophysiological and psychological responses to a laboratory task (changes and levels during the recovery period) in each group. Our results demonstrated that, compared to the control group, IPV perpetrators presented lower RSA levels (vagal tone). Even though the groups did not differ on their anger rumination or manifestation of aggression scores (except for proactive aggression), only in the IPV perpetrators, high anger rumination and reactive aggression partly explained the lower vagal tone (RSA levels) and high levels of anger state at post-task. Consequently, this study contributes to understanding the psychobiological basis for violence proneness in IPV perpetrators, making it possible to explore new therapeutic strategies.

Purpose
Recent research has identified different psychobiological mechanisms underlying Intimate Partner Violence (IPV). However, vagally mediated heart rate variability (vmHRV), a measure of parasympathetic activity, has been scarcely studied in IPV perpetrators. Low vmHRV activity has been found to be associated with maladaptive emotion regulation strategies and negative affect, whereas high vmHRV functioning has been related to higher social engagement, positive affect, prosocial behavior and compassion.
Methods
The present study examined vmHRV, mood state and prosocial behavior in a Compassion-eliciting Task, through a virtual reality paradigm, in 39 IPV offenders, compared to 42 general offenders (GO) and 43 non-forensic control participants. Additionally, it explored whether phasic vmHRV could explain the mood change in response to the Compassion Task.
Results
IPV offenders showed lower vmHRV activity during the task when compared to non-forensic participants. No significant differences were obtained between IPV and GO. Furthermore, higher vmHRV partially explained lower negative affect after the Compassion Task for the entire sample.
Conclusions
Findings suggest that IPV offenders experience difficulties connecting with others’ suffering. It also highlights that the use of biomarkers, such as vmHRV, in the study of criminogenic factors may provide a broader understanding that could promote more effective interventions.

The autonomic nervous system (ANS) functioning has been proposed as a relevant method to characterize the therapeutic needs of intimate partner violence (IPV) perpetrators. Nevertheless, research has neglected the influence of the ANS on socio-affective functions in this population. The aim of the present study was to analyze the psychophysiological activity of IPV perpetrators (n = 52) compared to controls (n = 46) following an empathic induction task, performed through negative emotion-eliciting videos. We employed two general ANS markers (heart rate [HR] and respiratory rate [RR]), two sympathetic-related indexes (pre-ejection period [PEP] and skin conductance level [SCL]) and a parasympathetic biomarker (respiratory sinus arrhythmia [RSA]). Additionally, we explored the impact of psychophysiological activity on prosocial behavior using Hare’s donation procedure. Compared to controls, IPV perpetrators reported lower HR and SCL following the task, as well as longer PEP, suggesting an attenuated sympathetic response to others’ distress. No differences in the RSA response pattern were found, however, IPV perpetrators displayed lower overall RSA levels throughout the protocol, indicative of reduced parasympathetic activity. Besides, while no differences in prosocial performance were observed, greater sympathetic responses and overall parasympathetic activity predicted increased donations across the sample. Thus, a high sympathetic and parasympathetic activity might influence the occurrence of prosocial behavior. The present study provides further evidence supporting that IPV perpetrators cope differently with others’ negative emotions. In line with this biopsychosocial perspective, insights are gained on the emotional processing of IPV perpetrators which, in turn, could contribute to improve IPV psychotherapeutic programs.

Research on female offenders’ emotional sphere remains limited, with fewer studies being conducted compared to male offenders. However, investigations have identified psychobiological mechanisms in non-forensic women underlying emotional processing. One such mechanism is the activity of the autonomic nervous system. Increased parasympathetic activity has been associated with higher emotional self-regulation, social engagement, and compassion. Therefore, the present study examined heart rate (HR), vagally mediated heart rate variability (vmHRV), mood correlations, and prosocial behavior during a compassion-eliciting task using a virtual reality paradigm in female offenders (n = 31) compared to non-forensic individuals (n = 35). The primary findings showed that offenders exhibited reduced vmHRV when engaging with others’ suffering. Additionally, during the period of compassionate motivation (prosocial task), offenders revealed lower HR levels. In contrast, non-forensic individuals showed the opposite pattern. However, there were no significant mood differences observed. Finally, lower vmHRV was associated with higher donation rates only within the non-forensic group. The results suggest that offenders may encounter challenges experiencing compassion, particularly when connecting with others’ suffering and when facing compassionate motivation, as reflected by diminished parasympathetic flexibility. Furthermore, this study highlights the potential for using biomarkers when examining criminogenic needs, offering a multidisciplinary understanding of socio-affective functions, paving the way for more effective interventions.