Background: Previous literature suggests that prevalence of cannabis use in the early phase of psychosis is high, and that early psychosis patients are at high-risk for violent behavior. However, the link between cannabis use and violent behavior in early psychosis patients is unclear. We carried out a study on a sample of early psychosis patients, in order to explore the impact of cannabis use on the risk of violent behavior (VB), while taking into account (1) potential confounding factors and, (2) interactions with other dynamic risk factors of VB.Method: In a sample of 265 early psychosis patients, treated at the Treatment and Early Intervention in Psychosis Program (TIPP) in Lausanne, we used logistic regression models to explore the link between various dynamic risk factors of VB [positive symptoms, substance use disorder (drugs including cannabis, alcohol and others drugs), insight, impulsivity, affective instability, and treatment adherence], and VB occurring during treatment. In order to understand hierarchical effects attributable to the combinations of risk factors on VB we conducted a Classification and Regression Tree (CART).Results: Our results show that cannabis use disorder is a risk factor for VB. The associations among risk factors suggest the presence of two patient profiles with an increased rate of VB: the first is composed of patients with cannabis use disorder and impulsivity, and the second of patients combining cannabis use disorder, absence of insight and non-adherence to treatment. The results also show the moderating role of insight and adherence to treatment on the rate of VB in patients with cannabis use disorder.Conclusion: This study suggests that cannabis use disorder is a significant risk factor for VB amongst early psychosis patients, particularly when combined with either impulsivity, lack of insight and non-adherence to treatment. These results suggest that preventive strategies could be developed on the basis of such patient profiles.

Early intervention strategies in psychotic disorders should include evaluation of impulsivity considering it is linked to increased risk of VB and may respond to treatment.

Some actuarial and structured professional judgment (SPJ) risk-assessment instruments have already demonstrated their validity and predictive accuracy in expert criminal forensic evaluations. In contrast, little is known about the effectiveness of instruments identifying protective factors in risk of recidivism prediction. The present study was designed to evaluate the validity and predictive accuracy of the Structured Assessment of Protective Factors for Violence Risk (SAPROF) in 94 violent and sexual violent offenders assessed in a Swiss pretrial criminal forensic context. The SAPROF showed good interrater reliability, and was significantly correlated to predominately dynamic instruments but not to predominately actuarial instruments. However, in terms of predictive accuracy, the SAPROF did not perform as well as expected when compared with other instruments and with previous SAPROF accuracy validation studies. These results have implications for the use of the SAPROF in criminal forensic contexts risk assessment.

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Age of onset, callous-unemotional (CU) traits and anger dysregulation have separately been proposed as relevant factors in explaining the heterogeneity of antisocial behaviour (ASB). Taking a dimensional perspective, this study examined the specific contributions and the mutual influences (i.e., interactions) of these three characteristics on specific dimensions of ASB (i.e., criminal behaviours and externalizing symptoms). Assessments were conducted on 536 youths from institutions with the youth psychopathic traits inventory (CU traits), the Massachusetts youth screening instrument-second version (anger dysregulation), the criminology questionnaire (criminal behaviours) and the child behavior checklist (externalizing symptoms), rated by both the youths and their carers. Using Bayes as estimators, the results revealed that the number and frequency of crimes (and, more specifically, damage to property, property offenses and media crimes) were explained by a specific contribution of each factor (age of onset, CU traits and anger dysregulation). Additionally, the interactions between age of onset and CU traits or anger dysregulation were relevant predictors of some types of crimes (i.e., damage to property, property offences and media crimes). Furthermore, when rated by youths, externalizing symptoms were explained by CU traits and anger dysregulation. However, when rated by the carer, anger dysregulation was more important in explaining externalizing symptoms. This study highlights the importance of considering these factors altogether and the value of using a dimensional perspective when examining the structure of ASB in youths. Consequently, future classifications should take into account the mutual account of these characteristics, which were previously studied separately.