Male Violent Offenders Research Articles

Prefrontal tDCS modulates risk-taking in male violent offenders

Detrimental decision-making is a major problem among violent offenders. Non-invasive brain stimulation offers a promising method to directly influence decision-making and has already been shown to modulate risk-taking in non-violent controls. We hypothesize that anodal transcranial direct current stimulation (tDCS) over the right dorsolateral prefrontal cortex beneficially modulates the neural and behavioral correlates of risk-taking in a sample of violent offenders. We expect offenders to show more risky decision-making than non-violent controls and that prefrontal tDCS will induce stronger changes in the offender group. In the current study, 22 male violent offenders and 24 male non-violent controls took part in a randomized double-blind sham-controlled cross-over study applying tDCS over the right dorsolateral prefrontal cortex. Subsequently, participants performed the Balloon Analogue Risk Task (BART) during functional magnetic resonance imaging (fMRI). Violent offenders showed significantly less optimal decision-making compared to non-violent controls. Active tDCS increased prefrontal activity and improved decision-making only in violent offenders but not in the control group. Also, in offenders only, prefrontal tDCS influenced functional connectivity between the stimulated area and other brain regions such as the thalamus. These results suggest baseline dependent effects of tDCS and pave the way for treatment options of disadvantageous decision-making behavior in this population.

Pinpointing change in virtual reality assisted treatment for violent offenders: a pilot study of Virtual Reality Aggression Prevention Training (VRAPT).

Preventing relapse into violence and its destructive consequences among persistent re-offenders is a primary concern in forensic settings. The Risk-Need-Responsivity framework models the best current practice for offender treatment, focused on building skills and changing pro-criminal cognitions. However, treatment effects are often modest, and the forensic context can obstruct the delivery of interventions. Developing treatments for offenders should focus on the best method of delivery to make "what works work." Virtual reality (VR)-assisted treatments such as Virtual Reality Aggression Prevention Training (VRAPT) are a new and innovative approach to offender treatment. This pilot study followed 14 male violent offenders who participated in VRAPT in a Swedish prison context and measured changes from pre-treatment to post-treatment and 3-month follow-up in targeted aggression, emotion regulation, and anger. It also investigated potential impact factors (pro-criminal cognitions, externalizing behaviors, psychosocial background, and childhood adverse experiences). In Bayesian linear mixed effects models, participants showed a high probability of change from pre-treatment to post-treatment and to follow-up on all outcome measures. All outcome measures demonstrated a low probability of change from post-treatment to follow-up. Analysis of reliable change showed that participants' results ranged from recovery to deterioration. We discuss the implications of the study for VRAPT's impact on the target group, those who might benefit from the approach, and suggested foci for future studies in the field of VR-assisted offender treatment. The study was preregistered at the International Standard Randomized Controlled Trial Number registry (https://doi.org/10.1186/ISRCTN14916410).

Does early adversity predict aggression among Chinese male violent juvenile offenders? The mediating role of life history strategy and the moderating role of meaning in life

BackgroundAdolescent aggression has long been of interest to researchers. However, few studies have examined the influencing factors and mechanisms of aggression among violent juvenile offenders. This study tests a moderated mediation model with Chinese male violent juvenile offenders as subjects. Specifically, it explores the relationship between early adversity and aggression, as well as the mechanisms of life history strategy and meaning in life in this relationship.MethodsA total of 537 Chinese male violent juvenile offenders completed the Childhood Environment Scale, the Life History Strategy Short Form Scale, the Aggression Questionnaire, and the Meaning in Life Questionnaire. After controlling for socioeconomic status (SES), the current cross-sectional study used structural equation modeling (SEM) to examine a moderated mediation model.ResultsThe results showed that life history strategy mediated the relationship between early adversity and aggression, and early adversity affected individuals’ aggression by accelerating their life history strategies. The results also showed that meaning in life moderated the relationship between early adversity and life history strategy. For individuals with high meaning in life scores, the negative predictive effect of early adversity on life history strategy was stronger than that for individuals with low meaning in life scores.ConclusionThe results of this study can advance the understanding of how early adversity affects aggression among violent juvenile offenders and provide theoretical support for prison staff to develop educational strategies and subsequent interventions.

Trait anger and aggression among male violent offenders: The mediating effect of sadistic impulse and the moderating effect of emotion regulation

We investigated the mediating role of sadistic impulse and the moderating role of emotion regulation strategy in the relationship between trait anger and aggressive behaviour in violent offenders. A total of 492 male violent offenders (mean age = 34.06 years, SD = 6.67 years) completed the Trait Anger Scale, Emotion Regulation Questionnaire, Short Sadistic Impulse Scale, and Impulsive/Premeditated Aggression Scale. We tested a moderated mediation model by multiple linear regression analysis (Bootstrap n = 5 000). The results showed that sadistic impulse mediated the relationship between trait anger and aggressive behaviour in violent offenders. Higher level of sadistic impulse was associated with a higher likelihood of aggressive behaviour. Emotion regulation strategy moderated the relationship between trait anger and aggressive behaviour. Specifically, those with lower emotional regulation were more likely to exhibit aggressive behaviour compared to those with higher emotional regulation. The mediated moderation model applied to both impulsive and premeditated aggression. In the low emotion regulation group, the mediating effects of trait anger on impulsive and premeditated aggression were significant. In the high emotion regulation group, the mediating effects of trait anger on impulsive and premeditated aggression were lower, but still significant. Our findings are consistent with the emotion regulation theory of aggression stating that people with sadism may assault others to improve their mood.

Severe violent victimization and labour market exclusion: The significance of the victim–offender overlap

Evidence that violent victimization is associated with an array of negative outcomes over the life-course is mounting. While its links to poor health have been extensively documented, socio-economic outcomes have been left relatively unexplored. In this study, Swedish population register data are utilized to examine the relationship between violent victimization and labour market exclusion, placing particular focus on the moderating role of offending and gender differences in this dynamic. Using data on 12 complete successive cohorts born 1975 to 1986, violent victimization is observed in young adulthood (age 20–24) using patient register data, and is measured as interpersonal violence resulting in hospital admission. Labour market exclusion is operationalized as being not in employment education or training and is observed at age 25 and 30. Linear probability models are estimated for men and women, respectively. The findings suggest that women who have been victims of violent crime face elevated risks of labour exclusion, in both the short and the long run, and regardless of criminal offending. Men, on the other hand, display no excess risk of labour market exclusion in the absence of violent offending. For the group of male violent offenders, however, victimization adds to the risk of labour market exclusion. Implications of the findings are discussed.

The Maltreatment-Aggression Link among Prosecuted Males: What about Psychopathy?

Criminal offenders constitute a high-risk sample regarding experiences of childhood maltreatment and engagement in severe aggression. Moreover, psychopathic traits are more common in samples of offenders than non-offenders. Although research has underlined the relationship between childhood maltreatment and adult aggression, the influence of psychopathy on this link is still unclear. We examined the dynamics of maltreatment, aggression, and psychopathy in a mixed sample of 239 male violent, sexual, and other offenders using latent factor structural equation modeling. We found a consistent positive association of maltreatment with aggression. Psychopathy did not mediate this relation. Maltreatment was not associated with psychopathy, although psychopathy had a positive effect on aggressive behavior. These dynamics appeared similar for violent, sexual, and other offenders. However, latent variables were constructed somewhat differently depending on the offender status. For instance, sexual abuse appeared to be of specific importance in sexual offenders. Violent offenders showed high rates of psychopathy compared to sexual and other offenders. The current findings may inspire future research to focus more closely on the different subtypes of psychopathy when examining its role in the prediction of aggression based on childhood maltreatment. Moreover, childhood maltreatment must not be neglected in treatment and prevention approaches aimed at reducing the risk of aggressive behavior.

Offending Trajectories in Violent Offenders: Criminal History and Early Life Risk Factors.

The understanding of offending, and thus its possible prevention, is expanded through longitudinal studies on criminal trajectories depicting early life risk factors. This longitudinal study aimed to explore criminal trajectories, criminal histories, and early life risk factors in a cohort of violent offenders. A Swedish nationally representative cohort of male violent offenders (n = 266), clinically assessed while imprisoned aged 18 to 25, was followed through national registers from age 15 to 25-34. Substantial differences in criminal histories between violent offenders and a matched comparison group (n = 10,000) were demonstrated. Five trajectory groups were identified: four persisting and one desisting. Although differences were observed between persisting trajectory groups, a higher prevalence of early life risk factors was generally displayed compared to the desisting, especially in conduct problems and experiences of out-of-home placements. Neurocognitive ability and prevalence of ADHD and autism were similar across trajectories. Severe early life risks highlight the population's need for early interventions.

Acute Exercise Improves Inhibitory Control but Not Error Detection in Male Violent Perpetrators: An ERPs Study With the Emotional Stop Signal Task.

Violence has been linked to the co-occurrence of cognitive dysfunction and altered activations in several brain regions. Empirical evidence demonstrated the benefits of acute exercise on motor inhibition and error detection and their neuronal processing. However, whether such effects also hold for the population with violent behaviors remains unknown. This study examined the effects of acute aerobic exercise on inhibitory control and error monitoring among violent offenders. Fifteen male violent offenders were counterbalanced into experimental protocols, which comprised a 30-min moderately aerobic exercise [60% heart rate (HR) reserve] and a 30-min reading control session. After each session, participants performed an emotional stop signal task while event-related potentials (ERPs) were recorded simultaneously. Results showed insignificant changes in ERPs components [i.e., N2, P3, error-related negativity (ERN), and error-positivity (Pe) amplitudes] and the behavioral performance in go condition, stop accuracy, and post-error adjustments by exercise. However, the current study demonstrated that the acute exercise facilitated stop signal reaction time (SSRT) when compared to the control session regardless of emotional conditions. This is the first research to exhibit the improvements in inhibitory performance by acute exercise for violent offenders. Most importantly, this effect was independent of affective settings, expanding the existing knowledge of the influences of acute exercise on cognition. Our findings implicate the perspective of acute exercise for clinical and correctional practices.

Association between S-COMT activity and impulsive and premeditated aggression in a population of violent offenders: preliminary results of a cross sectional study

Aggression can be conceptualised as a physical act towards another person, verbal offenses, destructive acts towards objects, and self-inflicted harmful acts. It is highly frequent in the context of Antisocial Personality Disorder (ASPD) and has been correlated to disturbances in the dopaminergic system. In the prefrontal cortex, the dopamine metabolism depends on catechol-O-methyltransferase (COMT). DRD2 receptors also play a role in the expression of aggression by modulating dopamine metabolism, in the striatum. In this study, we evaluated the association between COMT activity and type of aggression, in a sample of violent male offenders. Participants were subjected to sociodemographic, clinical, and psychometric evaluation through standardised instruments. Erythrocyte S-COMT activity was measured, and COMT and the DRD2 genotypes were analysed. Individuals displaying impulsive aggression showed lower S-COMT erythrocyte activity (p=0.026) and lower frequency of Val/Val (rs4680) genotype than individuals with premeditated aggression (p=0.047). S-COMT erythrocyte activity was positively correlated with the PCL-R total score (r=0.34; p=0.018). In conclusion, our preliminary results indicate that COMT can be associated to different aggression types in violent offenders, and it can represent a possible pharmacological target for the treatment of impulsive and premeditated aggression, in incarcerated patients.

Dark Tetrad and psychological distress among male violent offenders and male community adults

The first aim of this study was to explore differences between male violent offenders and male community adults in Dark Tetrad traits and psychological distress. The second aim was to investigate moderation effects of dark traits in the prediction of psychological distress based on the membership of violent offenders or community adults. The sample included 142 male violent offenders (M = 40.73, SD = 11.43) convicted of murder, severe murder, or rape, and 573 men from the community population in Serbia without a history of criminal convictions (M = 41.71, SD = 15.11). Serbian adaptations of the Short Dark Triad (SD3), Comprehensive Assessment of Sadistic Tendencies (CAST), and Clinical Outcomes in Routine Evaluation - Outcome Measure (CORE-OM) were used. Results showed that violent offenders had higher scores on psychopathy and problems in social and general functioning, while community adults had higher scores on narcissism. Furthermore, moderation analyses showed that physical sadism was significantly correlated with risk behaviors in the community adults, but not in violent offenders.

Altered Resting-State Functional Connectivity in the Default Mode Network in Male Juvenile Violent Offenders

Young males are often associated with more violence, leading to some serious negative consequences. However, the physiology and the neuroimaging patterns underlying juvenile violence remain unclear. Of the limited knowledge on juvenile violence, the default mode network has been known to be associated with its pathophysiology. This study aimed to investigate functional connectivity alterations of the default mode network in male juvenile violent offenders. 31 juvenile violent offenders in a high-security facility, who were convicted of aggressive behaviors by court, and 28 normal controls from a middle school were recruited as participants. They underwent a resting-state functional magnetic resonance imaging scan. And independent component analysis approaches were used to analyze their data. Compared to the normal controls, the juvenile violent offenders showed a different default mode network pattern, with the functional connectivity increased in the posterior cingulate, and decreased in the right middle temporal, left angular, right precuneus and right middle frontal cortex. Our findings revealed that the male juvenile violent offenders were associated with abnormal default mode network functional connectivity, which might be a neuroimaging basis for their tendency to violence.

Does attentional focus modulate affective information processing in male violent offenders with psychopathic traits?

Antisocial and psychopathic individuals are characterized by a reduced responsivity to affective information. Yet, the role of attentional processes as possible modulator of these deficits is poorly understood. The current study investigated early and late processing of emotional stimuli in a sample of incarcerated offenders while manipulating the attentional focus. Twenty-seven male violent offenders with psychopathic traits and 27 healthy controls completed two experimental tasks while electroencephalography (EEG) data were collected. Task 1 assessed indirect processing of emotional or neutral distractors during a perceptual judgment task, while Task 2 measured direct processing of the emotional or neutral stimuli and required participants to rate the stimuli regarding valence and arousal. EEG data indicated no differences in early stage processing (early posterior negativity) between the experimental groups. However, we found significant group differences with regard to the late processing stage (late positive potential, LPP). Controls showed increased LPP amplitudes in Task 2 as compared to Task 1, indicating that task demands (i.e., attentional focus) had an effect on the processing of the emotional stimuli. In contrast, LPP amplitudes in the violent offender group were largely unaffected by task demands, suggesting specific late alterations in the neural processing of emotional stimuli. In sum, this study provides new evidence for a modulatory impact of attention on affective information processing in male violent offenders with psychopathic traits.

Effectiveness of an Individual Cognitive-Behavioral Intervention for Serious, Young Male Violent Offenders: Randomized Controlled Study With Twenty-Four-Month Follow-Up.

Background: Psychological recidivism-reducing interventions with serious, young violent offenders in residential care have unsatisfactory effects. We tested if a complementary individual cognitive behavioral therapy (iCBT) intervention focusing problem-solving, cognitive self-control, and relapse prevention reduces criminal recidivism beyond usual institutional care encompassing interventions such as social skills training and prosocial modeling (treatment-as-usual; TAU).Method: We consecutively approached 115 eligible serious, male violent crime offenders in five residential treatment homes run by the Swedish National Board of Institutional Care. Eighty-one (70%) 16 to 21-year-old youth at medium-high violent recidivism risk were included and randomized to an individualized 15 to 20-session CBT intervention plus TAU (n = 38) or to TAU-only (n = 43), 4–6 months before release to the community. Participants were assessed pre- and post-treatment, at 12 months (self-reported aggressive behavior, reconvictions) and 24 months (reconvictions) after release. Intent-to-treat analyses were applied.Results: The violent reconviction rate was slightly higher for iCBT+TAU vs. TAU-only youth at 12 months (34 vs. 23%, d = 0.30, 95% CI: −0.24 to 0.84) and 24 months following release (50 vs. 40%, d = 0.23, 95% CI: −0.25 to 0.72), but neither of these differences were significant. Cox regression modeling also suggested non-significantly, negligibly to slightly more violent, and any criminal recidivism in iCBT+TAU vs. TAU-only youth during the entire follow-up. Further, we found no significant between-group differences in conduct problems, aggression, and antisocial cognitions, although both iCBT+TAU and TAU-only participants reported small to large within-group reductions across outcome measures at post-treatment. Finally, the 12-month follow-up suggested marginally more DSM-5 Conduct Disorder (CD) symptoms of “aggression to people and animals” in iCBT+TAU vs. TAU-only youth (d = 0.10, 95% CI: −0.40 to 0.60) although this difference was not significant.Conclusion: We found no additive effect of individual CBT beyond group-based TAU in residential psychological treatment for serious, young male violent offenders. Limited sample size and substantial treatment dropout reduced the robustness of intent-to-treat effect estimates. We discuss the possible impact of treatment dose and integrity, participant retention, and TAU quality.

"When I Take Drugs, I Don't Care": Insights into the Operational Dynamics of Male Violent Offenders in a Correctional Centre.

This study investigated the operational dynamics of male violent offenders incarcerated in Abakaliki custodial center, Nigeria. A cross-sectional survey research design was adopted and purposive technique used to recruit 260 inmates charged with violent offenses. The data generated from structured questionnaire were analyzed using Predictive Analytic Software (PAS), with ordinary least regression, descriptive statistics and spearman rank order correlation techniques, employed in testing the variables explored. Findings revealed that this population use drugs to enhance criminal performance through being brutal; instilling fear in victims to secure their total compliance and submission; and suppressing regret for their criminal acts. Heroin, followed by, cocaine, cannabis, tramadol, and multiple drug use, were commonly used drugs in the population surveyed, with their offenses ranging from cultism, armed robbery, murder and burglary to kidnapping and assault and battery. Gaining insights into the changing operational knowledge, procedures and dynamics of violent offenders will (re)direct policy approach and action that are capable of increasing public and custodial safety. It will also orient and direct practical prison reforms for successful rehabilitation and reintegration of released inmates into the free world.

Brain Basis of Psychopathy in Criminal Offenders and General Population.

Psychopathy is characterized by persistent antisocial behavior, impaired empathy, and egotistical traits. These traits vary also in normally functioning individuals. Here, we tested whether such antisocial personalities are associated with similar structural and neural alterations as those observed in criminal psychopathy. Subjects were 100 non-convicted well-functioning individuals, 19 violent male offenders, and 19 matched controls. Subjects underwent T1-weighted magnetic resonance imaging and viewed movie clips with varying violent content during functional magnetic resonance imaging. Psychopathic traits were evaluated with Levenson Self-Report Psychopathy Scale (controls) and Psychopathy Checklist-Revised (offenders). Psychopathic offenders had lower gray matter density (GMD) in orbitofrontal cortex and anterior insula. In the community sample, affective psychopathy traits were associated with lower GMD in the same areas. Viewing violence increased brain activity in periaqueductal grey matter, thalamus, somatosensory, premotor, and temporal cortices. Psychopathic offenders had increased responses to violence in thalamus and orbitofrontal, insular, and cingulate cortices. In the community sample, impulsivity-related psychopathy traits were positively associated with violence-elicited responses in similar areas. We conclude that brain characteristics underlying psychopathic spectrum in violent psychopathy are related to those observed in well-functioning individuals with asocial personality features.

Testing the Factor Structure of the Psychopathy Checklist: Screening Version (PCL:SV) in an Australian Violent Offender Population

Although psychopathy is a correlate of recidivism, including violent offending, the inclusion of antisocial behavior items in the Psychopathy Checklist (PCL) assessment instruments has been debated. Further, the latent factor structure underpinning the PCL measures has not been comprehensively validated in Australia. This study examined the construct validity of the PCL:SV in a sample of 192 Australian male violent offenders using structural equation modeling. The incremental validity of including the antisocial behavior items for predicting recidivism was also assessed. Approximately one-third of the sample had high scores on the PCL:SV. Construct analyses indicated strongest support for two distinct three-factor models of PCL psychopathy, with the established two- and four-factor models demonstrating poorer fit. The Antisocial factor improved predictive accuracy incrementally relative to the other three factors (Interpersonal, Affective, and Lifestyle). Area under the curve analyses revealed predictive accuracy for recidivism only for factors containing the antisocial behavior items. Findings contribute to the construct and predictive validity of the PCL measures and are discussed relative to contemporary forensic risk assessment practice.

The Utility of Physiological Measures in Assessing the Empathic Skills of Incarcerated Violent Offenders.

Since lack of empathy is an important indicator of violent behaviors, researchers need consistent and valid measures. This study evaluated the practical significance of a potential physiological correlate of empathy compared to a traditional self-report questionnaire in 18 male violent offenders and 21 general population controls. Empathy skills were assessed with the Interpersonal Reactivity Index (IRI) questionnaire. Heart-Rate Variability (HRV) was assessed with an electrocardiogram. The RMSSD (Root Mean Square of the Successive beat-to-beat Differences), an HRV index implicated in social cognition, was calculated. There were no group differences in IRI scores. However, RMSSD was lower in the offender group. Positive correlations between RMSSD and IRI subscales were found for controls only. We conclude that psychometric measures of empathy do not discriminate incarcerated violent offenders, and that the incorporation of psychophysiological measures, such as HRV, could be an avenue for forensic research on empathy to establish translatable evidence-based information.

An investigation of spitefulness in violent offenders: Associations with the dark triad and emotion dysregulation.

Spitefulness is the inclination to inflict harm to someone else even at one's own expenses. The development of a self-report measure (the Spitefulness Scale [SS]) has fostered the investigation of the relationships between spitefulness and aggression-related variables. The present study aims to investigate the construct of spitefulness in violent offenders. Through a translation/back-translation procedure, the SS was translated into Italian, and its psychometric properties were examined. A sample of 249 male violent offenders and 172 male community participants filled out the SS, the Self-Report Psychopathy Scale-IV, the Difficulties in Emotion Regulation Scale and the Dirty Dozen Scale. Confirmatory factor analysis results supported the unidimensional factor structure of the SS. Further results indicated that the scale had good internal consistency and met criteria for configural invariance, partial weak invariance and partial strong invariance across samples. Correlational analyses evidenced positive and significant associations between the SS scores and measures of the dark triad and emotion dysregulation. The offender sample scored significantly higher than the community sample on the SS. Results support the internal structure and construct validity of the SS, suggesting its potential utility for the study of the construct of spitefulness in violent offenders. © 2020 John Wiley & Sons, Ltd.

Exploring Traumatic Brain Injuries and Aggressive Antisocial Behaviors in Young Male Violent Offenders.

Background: Traumatic brain injury (TBI) is a major cause of disabilities and mortality worldwide, with higher prevalence in offender populations than in the general population. Previous research has strongly advocated increased awareness of TBI in offender populations. The aim of this study was to explore the prevalence and characteristics of TBI, and to investigate associations and interactions between TBI, aggressive antisocial behaviors, general intellectual functioning, and substance use disorders (SUD) in a well-characterized group of young violent offenders.Methods: The study investigated a cohort (n = 269) of 18 to 25-year-old male violent offenders in Sweden. Data on TBI (files + self-report), aggressive antisocial behaviors (Life History of Aggression), SUD (clinical interviews), and general intellectual functioning (General Ability Index, Wechsler Adult Intelligence Scales Third Edition) were collected between 2010 and 2012. Parametric (Student's t-test) and non-parametric (Mann-Whitney U-test, Spearman's rho, χ2, Kruskal Wallis test) inferential statistics were applied and effect sizes reported.Results: TBI, both with and without loss of consciousness, was common, with 77.5% of the offenders reporting having suffered at least one TBI during their lifetime. TBI was associated with an increased occurrence of aggressive antisocial behaviors and SUD, and offenders with both TBI and SUD evidenced the largest amount of aggressive antisocial behaviors. No clinically meaningful associations were found between TBI and general intelligence. Effect sizes were in the small to medium range.Conclusions: Our study confirms an increased prevalence of TBI among young violent offenders compared to the general population, as well as associations between TBI, aggressive antisocial behaviors, and SUD. However, it provides no information on the severity of the TBI, nor on the causality of the demonstrated associations. Nevertheless, TBI, and possible related deficits, need to be considered in the assessment and treatment of young violent offenders.

Effects of interaction of NOS1AP gene polymorphisms and childhood abuse on paranoid personality disorder features among male violent offenders in China

BackgroundParanoid Personality Disorder (PPD) results from a complex synergy between genetic and environmental factors. Childhood abuse is one of risk factors. Nitric Oxide Synthase 1 Adaptor Protein (NOS1AP) is a candidate gene of schizophrenia, which has similar pathophysiology to PPD. This study investigated the role of NOS1AP gene polymorphisms and a history of childhood abuse in predicting PPD features among male violent offenders in the Chinese Han population. MethodFour NOS1AP Single Nucleotide Polymorphisms (SNPs), rs4145621, rs3751284, rs348624 and rs6680461 were genotyped in a sample of 423 male prisoners. Participant evaluations included demographic information, measures of childhood abuse (Child Trauma Questionnaire, CTQ), and PPD features (Personality Diagnostic Questionnaire-4, PDQ-4). Participants were divided into a PPD group and non-PPD group assessed by PDQ-4. ResultsRegression analysis revealed that emotional abuse, NOS1AP SNPs rs348624 and rs4145621 predicted PPD features (P < 0.05) among prison samples. Significant interactions between childhood abuse history and NOS1AP SNPs rs3751284 and rs6680461 were also observed. Individuals carrying the C allele of rs3751284 were susceptible to PPD features when exposed to higher levels of emotional neglect (P < 0.05); Individuals with the G allele of rs6680461 were susceptible to PPD features when exposed to higher levels of emotional, physical and sexual abuse (P < 0.01). ConclusionsThese results suggest that the interaction between childhood abuse and NOS1AP gene polymorphisms may have an influence on PPD features, at least in male violent offenders.