Violence and schizophrenia

A standard measure to assess and predict violence is important for psychiatric services. No prospective study has examined the history of violence and heterogeneity of violence in predicting specific types of violence among inpatient with schizophrenia.

This study aimed to prospectively examine the accuracy of prediction of types of violence using the Chinese modified version of Violence Scale (VS-CM) among inpatients with schizophrenia based on their past history of violence and the real occurrence of violence during hospitalization.

A prospective cohort study design.

A total of 107 adult patients with schizophrenia spectrum disorders, consecutively admitted to an acute psychiatric ward of a university hospital in Taiwan, were recruited.

In addition to data about demographics and clinical illness, count records of the history of violence within one month prior to admission by interview and the actual occurrence of violence during the whole course of hospitalization by participant observation were collected using the VS-CM. Multivariate logistic analysis and area under the Receiver Operating Characteristic curve (AUC) analysis were applied to examine the predictive ability of the VS-CM.

A patient's history of violence assessed by the VS-CM predicted the actual occurrence of violence during hospitalization with the Odds Ratio of 17.5 (p = 0.001). The predictive accuracy of the VS-CM had high sensitivity (97.0%), moderate positive predictive value (71.4%), and high negative predictive value (87.5%); however, the specificity was relatively low (35.0%). The AUC was 79.5% using the total scale of the VS-CM and 70.7–74.5% using the subscales in predicting corresponding types of violence.

The VS-CM is a valid and reliable measure of potential violence. It can be applied to assess and predict specific types of violence among inpatient with schizophrenia.

The prevalence of homicide perpetrators with a diagnosis of schizophrenia is 6% in Western countries populations. The relationship between schizophrenia and homicide is complex and cannot be reduced to a simple causal link. The aim of this systematic review was to clarify the role of substance abuse in the commission of murder in people suffering from schizophrenia.

A systematic English-French Medline and EMBASE literature search of cohort studies, case-control studies and transversal studies published between January 2001 and December 2011 was performed, combining the MeSH terms “schizophrenia”, “psychotic disorders”, “homicide”, “violence”, “substance use disorder”, and the TIAB term “alcohol”. Abstract selection was based on the STROBE and PRISMA checklist for observational studies and systematic and meta-analysis studies, respectively.

Of the 471 selected studies, eight prospective studies and six systematic reviews and meta-analysis studies met the selection criteria and were included in the final analysis. Homicide committed by a schizophrenic person is associated with socio-demographic (young age, male gender, low socioeconomic status), historical (history of violence against others), contextual (a stressful event in the year prior to the homicide), and clinical risk factors (severe psychotic symptoms, long duration of untreated psychosis, poor adherence to medication). In comparison to the general population, the risk of homicide is increased 8-fold in schizophrenics with a substance abuse disorder (mainly alcohol abuse) and 2-fold in schizophrenics without any comorbidities. A co-diagnosis of substance abuse allows us to divide the violent schizophrenics into “early-starters” and “late-starters” according to the age of onset of their antisocial and violent behavior. The violence of the “early-starters” is unplanned, usually affects an acquaintance and is not necessarily associated with the schizophrenic symptoms. Substance abuse is frequent and plays an important role in the homicide commission. In addition, the risk of reoffending is high. In the “late-starters”, the violence is linked to the psychotic symptoms and is directed to a member of the family. The reoffence risk is low and it depends on the pursuit of care or not.

Defining subgroups of violent schizophrenic patients would avoid stigmatization and would help to prevent the risk of homicide by offering a multidisciplinary care which would take into account any substance abuse.

La prévalence de meurtriers avec un diagnostic de schizophrénie est de 6 % dans les pays occidentaux. La relation entre schizophrénie et homicide est complexe et ne peut se réduire à un simple lien de causalité. Nous proposons de clarifier, à travers une revue critique de la littérature, le rôle de la consommation de substances dans le risque de passage à l’acte homicide du sujet présentant une schizophrénie.

La recherche bibliographique des articles français et anglais a été réalisée par MEDLINE et EMBASE, sur la période de janvier 2001 à décembre 2011 inclusivement, combinant les mots [MESH] suivants : « schizophrenia », « psychotic disorders », « violence », « homicide », « substance use disorder », et le mot [TIAB] « alcohol ». La sélection des articles a été faite selon la cheklist Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) et Preferred Reporting Items of Systematic reviews and Meta-Analyses (PRISMA) pour respectivement les études observationnelles et les revues de la littérature et méta-analyses.

Sur les 471 articles initiaux, huit études prospectives et six revues systématiques de la littérature ou méta-analyses ont été retenues. L’homicide commis par un schizophrène est associé à des facteurs de risque socio-démographiques (âge jeune, sexe masculin, bas niveau socio-économique), historiques (antécédents de violence envers autrui), contextuels (évènement de vie stressant dans l’année précédant l’acte violent) et cliniques (symptomatologie psychotique aiguë, longue durée de psychose non traitée, mauvaise observance médicamenteuse). Par rapport à la population générale, le risque d’homicide est multiplié par 8 chez les schizophrènes présentant un abus de substances (principalement l’alcool) et par 2 chez les schizophrènes sans comorbidité. Le co-diagnostic d’abus de substances enrichit la clinique et la typologie des schizophrènes violents en différenciant les schizophrènes « early-starters » des « late-starters ». La violence des « early-starters », typiquement non planifiée et visant une personne de l’entourage amical, n’est pas nécessairement associée à la symptomatologie schizophrénique. La consommation de substances toxiques est fréquente et participe grandement au passage à l’acte. Le risque de récidive est élevé. Chez les « late-starters », la violence, le plus souvent en lien avec le délire à thématique paranoïde, est plus volontiers dirigée contre un membre de la famille. Le taux de récidive est faible, souvent tributaire de la poursuite — ou non — des soins.

La caractérisation de sous-groupes de patients schizophrènes violents permettrait d’éviter leur stigmatisation et d’aider à prévenir leur risque d’homicide, en offrant une prise en charge pluridisciplinaire prenant en compte la consommation de substances psycho-actives.