Risk factors for violent behaviour before and after the onset of schizophrenia spectrum disorder: A naturalistic case-control study in the Netherlands

Aggressive behaviors in first-episode psychosis: Distinction between the premorbid phase and the onset of psychosis

BACKGROUND

There is a well-established, although complex, association between aggression and psychosis, particularly in the early stages of illness. Some persons display aggressive behaviors even prior to psychosis onset. However, factors associated with aggressive behaviors prior to and at first-episode psychosis (FEP) onset remain underdocumented.

AIMS

The objective is two-fold: 1) to describe the prevalence of verbal and physical aggression occurring during the premorbid phase and at FEP onset; 2) distinguish the factors associated with aggressive behaviors during these two periods.

METHOD

Data on aggressive behaviors and factors potentially associated therewith were collected through research interviews and chart reviews among 567 persons with FEP admitted to two early intervention services in Montreal, Canada. Logistic regression analyses were conducted to identify factors associated with aggressive behaviors in both periods.

RESULTS

In the premorbid phase, 46.1 % (n = 257/558) of patients presented aggression (verbal: 35.9 %; towards objects: 24.2 %; against others: 27.9 %). At FEP, 18.1 % (n = 101/558) presented aggressive behaviors (verbal: 12.9 %; towards objects: 6.1 %; against others: 8.8 %). In the premorbid phase, lower education, prior justice involvement, cluster B personality traits/disorder and poorer functioning were associated with aggressive behaviors, while, at FEP, only prior homelessness was associated with aggression.

CONCLUSIONS

Aggressive behaviors are frequent in patients with FEP, prior onset and at FEP. Premorbid aggressive behaviors seem to be associated with premorbid difficulties. Early detection of youth with psychosis and those at high risk of psychosis, particularly homeless youth, is necessary to provide access to early specialized interventions and possibly prevent aggressive behaviors and their consequences.

Structural brain abnormalities and aggressive behaviour in schizophrenia: Mega-analysis of data from 2095 patients and 2861 healthy controls via the ENIGMA consortium

Background

Schizophrenia is associated with an increased risk of aggressive behaviour, which may partly be explained by illness-related changes in brain structure. However, previous studies have been limited by group-level analyses, small and selective samples of inpatients and long time lags between exposure and outcome.

Methods

This cross-sectional study pooled data from 20 sites participating in the international ENIGMA-Schizophrenia Working Group. Sites acquired T1-weighted and diffusion-weighted magnetic resonance imaging scans in a total of 2095 patients with schizophrenia and 2861 healthy controls. Measures of grey matter volume and white matter microstructural integrity were extracted from the scans using harmonised protocols. For each measure, normative modelling was used to calculate how much patients deviated (in z-scores) from healthy controls at the individual level. Ordinal regression models were used to estimate the associations of these deviations with concurrent aggressive behaviour (as odds ratios [ORs] with 99% confidence intervals [CIs]). Mediation analyses were performed for positive symptoms (i.e., delusions, hallucinations and disorganised thinking), impulse control and illness insight. Aggression and potential mediators were assessed with the Positive and Negative Syndrome Scale, Scale for the Assessment of Positive Symptoms or Brief Psychiatric Rating Scale.

Results

Aggressive behaviour was significantly associated with reductions in total cortical volume (OR [99% CI] = 0.88 [0.78, 0.98], p = .003) and global white matter integrity (OR [99% CI] = 0.72 [0.59, 0.88], p = 3.50 × 10-5) and additional reductions in dorsolateral prefrontal cortex volume (OR [99% CI] = 0.85 [0.74, 0.97], p =.002), inferior parietal lobule volume (OR [99% CI] = 0.76 [0.66, 0.87], p = 2.20 × 10-7) and internal capsule integrity (OR [99% CI] = 0.76 [0.63, 0.92], p = 2.90 × 10-4). Except for inferior parietal lobule volume, these associations were largely mediated by increased severity of positive symptoms and reduced impulse control.

Conclusions

This study provides evidence that the co-occurrence of positive symptoms, poor impulse control and aggressive behaviour in schizophrenia has a neurobiological basis, which may inform the development of therapeutic interventions.