Murder and psychosis: Neuropsychological profiles of homicide offenders with schizophrenia

Delusions and Delinquencies: A Comparison of Violent and Non-Violent Offenders With Schizophrenia Spectrum Disorders

The relationship between schizophrenia spectrum disorders (SSD) and violent offending has long been the subject of research. The present study attempts to identify the content of delusions, an understudied factor in this regard, that differentiates between violent and non-violent offenses. Limitations, clinical relevance, and future directions are discussed. Employing a retrospective study design, machine learning algorithms and a comprehensive set of variables were applied to a sample of 366 offenders with a schizophrenia spectrum disorder in a Swiss forensic psychiatry department. Taking into account the different contents and affects associated with delusions, eight variables were identified as having an impact on discriminating between violent and non-violent offenses with an AUC of 0.68, a sensitivity of 30.8%, and a specificity of 91.9%, suggesting that the variables found are useful for discriminating between violent and non-violent offenses. Delusions of grandiosity, delusional police and/or army pursuit, delusional perceived physical and/or mental injury, and delusions of control or passivity were more predictive of non-violent offenses, while delusions with aggressive content or delusions associated with the emotions of anger, distress, or agitation were more frequently associated with violent offenses. Our findings extend and confirm current research on the content of delusions in patients with SSD. In particular, we found that the symptoms of threat/control override (TCO) do not directly lead to violent behavior but are mediated by other variables such as anger. Notably, delusions traditionally seen as symptoms of TCO, appear to have a protective value against violent behavior. These findings will hopefully help to reduce the stigma commonly and erroneously associated with mental illness, while supporting the development of effective therapeutic approaches.

Exploring Characteristics of Homicide Offenders With Schizophrenia Spectrum Disorders Via Machine Learning

The link between schizophrenia and homicide has long been the subject of research with significant impact on mental health policy, clinical practice, and public perception of people with psychiatric disorders. The present study investigates factors contributing to completed homicides committed by offenders diagnosed with schizophrenia referred to a Swiss forensic institution, using machine learning algorithms. Data were collected from 370 inpatients at the Centre for Inpatient Forensic Therapy at the Zurich University Hospital of Psychiatry. A total of 519 variables were explored to differentiate homicidal and other (violent and non-violent) offenders. The dataset was split employing variable filtering, model building, and selection embedded in a nested resampling approach. Ten factors regarding criminal and psychiatric history and clinical factors were identified to be influential in differentiating between homicidal and other offenders. Findings expand the research on influential factors for completed homicide in patients with schizophrenia. Limitations, clinical relevance, and future directions are discussed.

Neurocognitive Suicide and Homicide Markers in Patients with Schizophrenia Spectrum Disorders: A Systematic Review

Suicide and homicide are considered important problems in public health. This study aims to identify the cognitive performance of suicidal and homicidal behaviors in people with schizophrenia spectrum disorders, as well as examining whether there are shared neuropsychological mechanisms. A systematic review of the recent literature was carried out from September 2012 to June 2022 using the Medline (via PubMed), Scopus, Embase, and Cochrane databases. Among the 870 studies initially identified, 23 were finally selected (15 related to suicidal behaviors and 8 to homicidal behaviors). The results evidenced a relationship between impairment of cognitive performance and homicidal behavior; meanwhile, for suicidal behaviors, no consistent results were found. High neuropsychological performance seems to act as a protective factor against violent behavior in people with schizophrenia spectrum disorders, but not against suicidal behavior; indeed, it can even act as a risk factor for suicidal behavior. To date, there is insufficient evidence that shared neurocognitive mechanisms exist. However, processing speed and visual memory seem to be affected in the presence of both behaviors.

Effects of a 12-Session Symptom Self-Management Course on Forensic Psychiatric Inpatients' Auditory Hallucinations and Anxiety

The purpose of this clinical dissemination project was to evaluate changes in intensity of unpleasant auditory hallucinations (AH) and level of anxiety after forensic psychiatric inpatients attended an evidence-based symptom self-management course. The course was taught twice to patients with schizophrenic disorders. Data were collected using five self-rating measures. Seventy percent of participants reported reduced AH and anxiety; 100% reported helpfulness of being with others with similar symptoms; 90% would recommend the course to others. The course facilitator reported: improved communication, comfort, and effectiveness working with people with AH, plans to teach the course again and recommend it to colleagues.

The Doppelgänger phenomenon and death: a peculiar case of homicide by a subject with first-episode psychosis

The Doppelgänger phenomenon refers to the experience of a direct encounter with one's self, characteriswed by: (i) the perception of a figure with one's own identical physical features; or (ii) the apprehension that the perceived figure shares the same personality and identity. The Doppelgänger does not only look like the same person, it is his/her double. The perceptual element is usually a hallucination, although occasionally a false perception of an actual figure may be involved. This phenomenon has been described in individuals suffering from overwhelming fear, severe anxiety or intoxication, epilepsy, as well as in the sleep-wakefulness transition. It has also been reported in major psychoses. The fear of imminent death often precedes the Doppelgänger experience. This report presents the case of a 30-year-old man, Mr. Y, who was stabbed to death by Mr. X, his "double". The aggressor and his victim, although not related, were truly doubles; remarkably, they shared the same name and surname, age, professional activity and place of work. Moreover, they attended the same sports center but barely knew each other. The forensic psychiatric evaluations in Mr. X, subsequent to the crime committed, were suggestive of a psychotic condition. This case is unique in the scientific literature. In the most serious psychotic forms, the issue of the "double" calls into question not only the dissociative processes involved in the etiopathogenesis of the disorder, but also bio-psycho-social elements, as well as personal data in this case, which made the victim and the aggressor "identical". In the context of psychopathological functioning, the delusional mood (Wahnstimmung) that precedes the development of delirium is a sort of gateway to an impending psychotic illness, involving delusional awareness or mood (atmosphere). In psychosis, splitting is the main issue and this influence is seen as an evil, foreign, apocalyptic and unknown side no longer recognised as belonging to the self even in a physical sense. In such a situation, it is felt that the only way to survive is by suppressing one's double as a defense against disorganisation of the self.

Keeping the balance: Trade-offs between human brain evolution, autism, and schizophrenia

The unique qualities of the human brain are a product of a complex evolutionary process. Evolution, famously described by François Jacob as a “tinkerer,” builds upon existing genetic elements by modifying and repurposing them for new functions. Genetic changes in DNA may lead to the emergence of new genes or cause altered gene expression patterns. Both gene and regulatory element mutations may lead to new functions. Yet, this process may lead to side-effects. An evolutionary trade-off occurs when an otherwise beneficial change, which is important for evolutionary success and is under strong positive selection, concurrently results in a detrimental change in another trait. Pleiotropy occurs when a gene affects multiple traits. Antagonistic pleiotropy is a phenomenon whereby a genetic variant leads to an increase in fitness at one life-stage or in a specific environment, but simultaneously decreases fitness in another respect. Therefore, it is conceivable that the molecular underpinnings of evolution of highly complex traits, including brain size or cognitive ability, under certain conditions could result in deleterious effects, which would increase the susceptibility to psychiatric or neurodevelopmental diseases. Here, we discuss possible trade-offs and antagonistic pleiotropies between evolutionary change in a gene sequence, dosage or activity and the susceptibility of individuals to autism spectrum disorders and schizophrenia. We present current knowledge about genes and alterations in gene regulatory landscapes, which have likely played a role in establishing human-specific traits and have been implicated in those diseases.

Schizophrenia: the new etiological synthesis

Schizophrenia has been an evolutionary paradox: it has high heritability, but it is associated with decreased reproductive success. The causal genetic variants underlying schizophrenia are thought to be under weak negative selection. To unravel this paradox, many evolutionary explanations have been suggested for schizophrenia. We critically discuss the constellation of evolutionary hypotheses for schizophrenia, highlighting the lack of empirical support for most existing evolutionary hypotheses-with the exception of the relatively well supported evolutionary mismatch hypothesis. It posits that evolutionarily novel features of contemporary environments, such as chronic stress, low-grade systemic inflammation, and gut dysbiosis, increase susceptibility to schizophrenia. Environmental factors such as microbial infections (e.g., Toxoplasma gondii) can better predict the onset of schizophrenia than polygenic risk scores. However, researchers have not been able to explain why only a small minority of infected people develop schizophrenia. The new etiological synthesis of schizophrenia indicates that an interaction between host genotype, microbe infection, and chronic stress causes schizophrenia, with neuroinflammation and gut dysbiosis mediating this etiological pathway. Instead of just alleviating symptoms with drugs, the parasite x genotype x stress model emphasizes that schizophrenia treatment should focus on detecting and treating possible underlying microbial infection(s), neuroinflammation, gut dysbiosis, and chronic stress.

Remodelling criminal insanity: Exploring philosophical, legal, and medical premises of the medical model used in Norwegian law

This paper clarifies the conceptual space of discussion of legal insanity by considering the virtues of the 'medical model' model that has been used in Norway for almost a century. The medical model identifies insanity exclusively with mental disorder, and especially with psychosis, without any requirement that the disorder causally influenced the commission of the crime. We explore the medical model from a transdisciplinary perspective and show how it can be utilised to systematise and reconsider the central philosophical, legal and medical premises involved in the insanity debate. A key concern is how recent transdiagnostic and dimensional approaches to psychosis can illuminate the law's understanding of insanity and its relation to mental disorder. The authors eventually raise the question whether the medical model can be reconstructed into a unified insanity model that is valid across the related disciplinary perspectives, and that moves beyond current insanity models.

Increased prevalence of psychopathy and childhood trauma in homicide offenders with schizophrenia compared to nonviolent individuals with schizophrenia

Purpose: Schizophrenia is associated with an increased homicide risk. Personality pathology, particularly antisocial personality disorder and psychopathic traits, has been associated with increased violence risk in schizophrenia. Childhood trauma, more specifically physical abuse, has been associated with violence risk in healthy populations and in individuals with mental illness. It is, however, unclear how childhood trauma relates to homicide in schizophrenia. This is, to our knowledge, the first study to concurrently examine personality pathology and childhood trauma in a group consisting solely of homicide offenders with schizophrenia (HOS). HOS is compared to nonviolent participants with the same diagnosis (non-HOS). Additionally, currently assessed demographical and clinical characteristics of a Norwegian sample of HOS are reported. Materials and methods: Two groups of participants with schizophrenia were recruited in collaboration with in and outpatient clinics across Norway, HOS (n= 26) and non-HOS (n= 28). Assessments of personality pathology and childhood trauma were conducted, and information about clinical and demographical characteristics was registered. Results: HOS participants had significantly higher psychopathy scores, and more frequently reported moderate to severe childhood physical abuse than non-HOS participants. When simultaneously added to a logistic regression model, only psychopathy uniquely contributed to explaining group membership. Conclusions: Psychopathy and physical abuse was more prevalent among HOS participants compared to non-HOS, but only psychopathy independently predicted homicidal status. These results confirm the importance of including an evaluation of psychopathic traits in violence risk assessments of individuals with schizophrenia.

Impaired neuropsychological profile in homicide offenders with schizophrenia

BACKGROUND

Our ability to predict and prevent homicides committed by individuals with schizophrenia is limited. Cognitive impairments are associated with poorer functional outcome in schizophrenia, possibly also homicide. The aim of the current study was to investigate global and specific cognition among homicide offenders with schizophrenia (HOS).

METHODS

Twenty-six HOS were compared to 28 individuals with schizophrenia and no history of violence (non-HOS), and a group of healthy controls (HC, n = 151). HOS and non-HOS participants were recruited from in- and outpatient units across Norway. An extensive neuropsychological test battery was administered.

RESULTS

HOS participants performed significantly weaker than HC in all cognitive domains. Further, statistically significant differences between HOS and non-HOS participants were found for IQ (d = 0.52) and verbal learning (d = 0.82), with larger impairments in the HOS compared to the non-HOS group.

CONCLUSIONS

Our results indicate that HOS participants show clinically significant impairments in global and specific cognition.

Psychosis and homicide

PURPOSE OF REVIEW

The contribution of people with psychosis to homicide statistics is small, but there is a statistically significantly higher rate of homicide among them than in the general population. Legal authorities and the wider public call for more information. Our aim was a narrative synthesis of empirical literature generated by systematic searches for the five complete years 2013-2017.

RECENT FINDINGS

One article showed that people with psychosis are five times more likely to be homicide victims than those without, but focus remains on perpetrators. Consensus is that although psychotic symptoms contribute to homicidal acts, so do many of the variables that increase homicide risk more generally - including substance use, trauma histories and access to weapons; thus, both the epidemiology of homicide and some details, like method, may be country specific. In 2013-2017, variation in service provision as a risk factor for homicide has emerged more clearly but, overall, research made few homicide-specific advances.

SUMMARY

Criminal homicide is, fortunately, uncommon in most countries. Homicides by people with psychosis are so rare that they do not rate mention in the 2013 United Nations Global Survey of Homicide. This may account for the limitations to much research for this group. Despite some homicide-specific evidence of advantage for early intervention for psychosis, impact of improving treatment - the most promising way forward - will generally have to be inferred from the not entirely satisfactory surrogate of effects of treatment on violent offending more generally.

Differences in Neuropsychological Functioning Between Homicidal and Nonviolent Schizophrenia Samples

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.

Clonal Characteristics of T-Cell Receptor Repertoires in Violent and Non-violent Patients With Schizophrenia

Background: Activated or impaired T-cell function in inflammatory and degenerative process can contribute to the risk and progression of schizophrenia. This study used immune repertoire sequencing to investigate the T-cell receptor beta variable chain (TRBV) presence in blood mononuclear cells in the violent or non-violent schizophrenic patients. Methods: Ten violent and 10 non-violent schizophrenic patients and 8 matched healthy controls were enrolled. The Brief Psychiatric Rating Scale (BPRS) was used to evaluate patients' psychiatric symptoms. The level of aggression was assessed using the Modified Overt Aggression Scale (MOAS). The complementarity-determining region 3 (CDR3) of TRBV was detected using multiplex-PCR and high-throughput sequencing. Results: The TCR repertoire diversity were no significant differences in the Shannon-Wiener or inverse Simpson diversity index between three groups. Principal component analysis (PCA) of TRBV composition and abundance showed that principal component 1 and principal component 2 can explain 28.88 and 13.24% of total variation, respectively. Schizophrenic patients (violent and non-violent) had significantly different V gene distribution compared to healthy controls. In particular, TRBV2 occurred at a significantly higher frequency in the violent schizophrenia group than in the non-violent schizophrenia and healthy control groups, and TRBV7-2 occurred at a significantly higher frequency in the non-violent schizophrenia group than in the violent schizophrenia and healthy control groups. Conclusions: The results suggest that violent and non-violent schizophrenic patients carry abnormal T-cell receptor repertoires, and these data provide a useful clue to explore the etiology of violent behavior in schizophrenia.