Few studies have compared performance on neurocognitive measures between violent and nonviolent schizophrenia samples. A better understanding of neurocognitive dysfunction in violent individuals with ...schizophrenia could increase the efficacy of violence reduction strategies and aid in risk assessment and adjudication processes. This study aimed to compare neuropsychological performance between 25 homicide offenders with schizophrenia and 25 nonviolent schizophrenia controls. The groups were matched for age, race, sex, and handedness. Independent t‐tests and Mann–Whitney U‐tests were used to compare the schizophrenia groups’ performance on measures of cognition, including composite scores assessing domain level functioning and individual neuropsychological tests. Results indicated the violent schizophrenia group performed worse on measures of memory and executive functioning, and the Intellectual Functioning composite score, when compared to the nonviolent schizophrenia sample. These findings replicate previous research documenting neuropsychological deficits specific to violent individuals with schizophrenia and support research implicating fronto‐limbic dysfunction among violent offenders with schizophrenia.
Abstract
Objective
Few studies have examined the use of embedded validity indicators (EVIs) in criminal-forensic practice settings, where judgements regarding performance validity can carry severe ...consequences for the individual and society. This study sought to examine how various EVIs perform in criminal defendant populations, and determine relationships between EVI scores and intrapersonal variables thought to influence performance validity.
Method
Performance on 16 empirically established EVI cutoffs were examined in a sample of 164 criminal defendants with valid performance who were referred for forensic neuropsychological evaluation. Subsequent analyses examined the relationship between EVI scores and intrapersonal variables in 83 of these defendants.
Results
Half of the EVIs (within the Wechsler Adult Intelligence Scale Digit Span Total, Conners’ Continuous Performance Test Commissions, Wechsler Memory Scale Logical Memory I and II, Controlled Oral Word Association Test, Trail Making Test Part B, and Stroop Word and Color) performed as intended in this sample. The EVIs that did not perform as intended were significantly influenced by relevant intrapersonal variables, including below-average intellectual functioning and history of moderate–severe traumatic brain injury and neurodevelopmental disorder.
Conclusions
This study identifies multiple EVIs appropriate for use in criminal-forensic settings. However, based on these findings, practitioners may wish to be selective in choosing and interpreting EVIs for forensic evaluations of criminal court defendants.
Intimate partner violence (IPV) is a widespread crime that victimizes over 4-million women per year in the United States and results in significant monetary cost and unmeasured physical and ...psychological consequences for victims. Specialized IPV offender treatment programs demonstrate limited effectiveness, which may be due to an insufficient understanding of the factors that differentiate between IPV perpetrators and non-IPV violent offenders. In this study, we utilized classification and regression tree (CART) analysis to identify combinations of factors that best discriminate IPV perpetrators from non-IPV violent offenders. We also compared cognitive abilities between IPV perpetrators and non-IPV violent offenders using standardized neurocognitive tests. CART analysis presented two pathways for identifying offenders as IPV perpetrators: (a) extensive nonviolent criminal history and (b) moderate-to-severe expression of interpersonal traits of psychopathy without attentional deficits. In addition, a third pathway identified non-IPV violent offenders: (c) low levels of interpersonal psychopathic traits and no history of neurodevelopmental diagnosis. IPV perpetrators demonstrated intact cognition relative to test norms, and study groups did not significantly differ on cognitive performance. These findings suggest that individuals with multiple arrests for nonviolent crime or individuals with interpersonal traits of psychopathy without attentional difficulties may be at enhanced risk for IPV perpetration.
Few studies have examined life history and cognitive characteristics unique to female homicide offenders. Understanding these characteristics could aid in risk assessment for extreme violence in this ...group of offenders. The current study utilized t‐tests or chi‐square tests to compare 27 female and 81 male homicide offenders on psychiatric, neurologic, criminal, and cognitive characteristics. Additionally, we explored the role of abuse history in female offenders through Kruskal–Wallis or Fisher's exact tests. Results indicate that in comparison with male counterparts, females are more likely to have history of mood disorder, borderline personality disorder, and abuse. Cognitively, female homicide offenders exhibit circumscribed cognitive impairment in verbal abilities and perform similarly to male homicide offenders across most cognitive tasks. Within the female offender group, history of sexual abuse is associated with higher rates of impulsive homicide and poorer verbal abilities. These findings provide preliminary evidence for distinct factors associated with homicide in women.
Homicide injury severity (HIS), the degree of physical injury inflicted on a victim during a homicide, has emerged as a relevant criminological variable. However, little is known regarding the ...offender characteristics and criminological variables that may be associated with greater HIS. Data (demographic, cognitive, and criminological variables) from forensic neuropsychological evaluations of N = 101 offenders convicted of murder, were explored in relation to the Homicide Injury Scale. Numerous factors were related to HIS. Results partially replicate prior findings of factors associated with violent offending and provide preliminary evidence for distinct risk factors for inflicting severe injury during a homicide.
Domestic homicide is the most extreme form of domestic violence and one of the most common types of homicide. The objective was to examine differences between spontaneous domestic homicide and ...nondomestic homicide offenders regarding demographics, psychiatric history, crime characteristics, and neuropsychological status, utilizing neuropsychological test data from forensic examinations of 153 murderers. Using standard crime classification criteria, 33% committed spontaneous domestic homicides (SDH) and 61% committed nondomestic homicides (NDH). SDH offenders were more likely to manifest psychotic disorders, but less likely to be diagnosed with antisocial personality disorder or to have prior felony convictions. SDH offenders manifested significantly worse neuropsychological impairments than NDH offenders. The mean number of victims was lower for the SDH than the NDH group and only 14% of SDH offenders used a firearm, whereas 59% of NDH offenders used a firearm. These findings corroborate the notion that spontaneous domestic homicide may represent a discernible criminological phenotype.
Abstract As mass murders become more prominent throughout the United States, the ability to predict and prevent these crimes becomes imperative. Research indicates that mass murderers experience ...increased incidence of psychosocial stressors, psychiatric issues, and head trauma. However, few scientific studies of mass murderers exist, and no prior study has examined the associations between neurocognitive abilities and mass murder. We examined demographic, neurologic, psychiatric, substance use, criminal, and neurocognitive characteristics of mass murderers and compared mass murderers to single victim murderers on these characteristics. Additionally, we proposed a sub-classification of mass murderers based on the degree of relationship with their victims, and explored group differences in the aforementioned characteristics. Results suggested that mass murderers exhibit low average abilities across cognitive domains. Mass murder was associated with higher levels of premeditation and better cognitive abilities than single victim murder. Subgroups of mass murderers were distinguishable based on demographic and psychiatric variables, but exhibited similar cognitive profiles. Our findings suggest that mass murderers may possess the cognitive ability to engage in preventative or rehabilitative efforts, and that subtyping based on the degree of victim relationship may be important in this group of offenders.
This study examined neuropsychological characteristics of offenders who killed children. Although prior studies have focused on filicide and neonaticide, children are killed in a variety of contexts. ...This study used a diverse sample of individuals (N = 33) accused of killing one or more children, referred for forensic neuropsychological evaluation. Across all cognitive domains (intellectual functioning, attention/working memory/processing speed, memory, reasoning/executive functioning, language), mean scores fell in the low average to average range. Offenders who solely killed children were less likely to do so in a premeditated fashion, were more likely to use manual means (e.g., drowning or beating), and scored lower on measures of language and verbal memory, compared with those who also killed adults as part of the offense. Contrary to prior findings, few gender differences were evident in this group of offenders. Findings highlight meaningful heterogeneity in offenders who kill children, which may inform prevention, treatment, and risk assessment.
The notion that affective/impulsive violence and predatory/instrumental violence constitute distinct behavioral phenotypes has been supported in the forensic literature. Prior research suggests that ...offenders committing affective/impulsive homicide exhibit differing patterns of anomalous regional brain activation and decreased executive functions relative to predatory/instrumental homicide offenders. However, no prior research has examined the extent to which murderers who kill impulsively versus those who kill as the result of the execution of a premeditated strategic plan differ with regard to other neuropsychological functions and intelligence. Based on established criteria, we classified 77 murderers into affective/impulsive and predatory/instrumental groups, and compared their performance on standardized measures of intelligence and neuropsychological functioning. Results revealed significant differences between the affective/impulsive group (mean Full Scale IQ = 79) and the predatory/instrumental group (mean Full Scale IQ = 93) on indices of intelligence, memory, attention, and executive functioning. Most differences remained significant after controlling for relevant background factors.
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