Disturbances in Response Inhibition and Emotional Processing as Potential Pathways to Violence in Schizophrenia: A High-Density Event-Related Potential Study

OBJECTIVE: Increased susceptibility to emotional triggers and poor response inhibition are important in the etiology of violence in schizophrenia. Our goal was to evaluate abnormalities in neurophysiological mechanisms underlying response inhibition and emotional processing in violent patients with schizophrenia (VS) and 3 different comparison groups: nonviolent patients (NV), healthy controls (HC) and nonpsychotic violent subjects (NPV). METHODS: We recorded high-density Event-Related Potentials (ERPs) and behavioral responses during an Emotional Go/NoGo Task in 35 VS, 24 NV, 28 HC and 31 NPV subjects. We also evaluated psychiatric symptoms and impulsivity. RESULTS: The neural and behavioral deficits in violent patients were most pronounced when they were presented with negative emotional stimuli: They responded more quickly than NV when they made commission errors (ie, failure of inhibition), and evidenced N2 increases and P3 decreases. In contrast, NVs showed little change in reaction time or ERP amplitude with emotional stimuli. These N2 and P3 amplitude changes in VSs showed a strong association with greater impulsivity. Besides these group specific changes, VSs shared deficits with NV, mostly N2 reduction, and with violent nonpsychotic subjects, particularly P3 reduction. CONCLUSION: Negative affective triggers have a strong impact on violent patients with schizophrenia which may have both behavioral and neural manifestations. The resulting activation could interfere with response inhibition. The affective disruption of response inhibition, identified in this study, may index an important pathway to violence in schizophrenia and suggest new modes of treatment

Neuroanatomical Abnormalities in Violent Individuals with and without a Diagnosis of Schizophrenia

Several structural brain abnormalities have been associated with aggression in patients with schizophrenia. However, little is known about shared and distinct abnormalities underlying aggression in these subjects and non-psychotic violent individuals. We applied a region-of interest volumetric analysis of the amygdala, hippocampus, and thalamus bilaterally, as well as whole brain and ventricular volumes to investigate violent (n = 37) and non-violent chronic patients (n = 26) with schizophrenia, non-psychotic violent (n = 24) as well as healthy control subjects (n = 24). Shared and distinct volumetric abnormalities were probed by analysis of variance with the factors violence (non-violent versus violent) and diagnosis (non-psychotic versus psychotic), adjusted for substance abuse, age, academic achievement and negative psychotic symptoms. Patients showed elevated vCSF volume, smaller left hippocampus and smaller left thalamus volumes. This was particularly the case for non-violent individuals diagnosed with schizophrenia. Furthermore, patients had reduction in right thalamus size. With regard to left amygdala, we found an interaction between violence and diagnosis. More specifically, we report a double dissociation with smaller amygdala size linked to violence in non-psychotic individuals, while for psychotic patients smaller size was linked to non-violence. Importantly, the double dissociation appeared to be mostly driven by substance abuse. Overall, we found widespread morphometric abnormalities in subcortical regions in schizophrenia. No evidence for shared volumetric abnormalities in individuals with a history of violence was found. Finally, left amygdala abnormalities in non-psychotic violent individuals were largely accounted for by substance abuse. This might be an indication that the association between amygdala reduction and violence is mediated by substance abuse. Our results indicate the importance of structural abnormalities in aggressive individuals

Efficacy of antipsychotic drugs against hostility in the European First-Episode Schizophrenia Trial (EUFEST)

To compare the effects of haloperidol, amisulpride, olanzapine, quetiapine, and ziprasidone on hostility in first-episode schizophrenia, schizoaffective disorder, or schizophreniform disorder. We used the data acquired in the European First-Episode Schizophrenia Trial, an open, randomized trial (conducted in 14 countries) comparing 5 antipsychotic drugs in 498 patients aged 18-40 years with first-episode schizophrenia, schizoaffective disorder, or schizophreniform disorder. DSM-IV diagnostic criteria were used. Patients were assessed between December 23, 2002 and January 14, 2006. Most subjects joined the study as inpatients and then continued with follow-ups in outpatient clinic visits. The Positive and Negative Syndrome Scale (PANSS) was administered at baseline and at 1, 3, 6, 9, and 12 months after randomization. We analyzed the scores on the PANSS hostility item in a subset of 302 patients showing at least minimal hostility (a score > 1) at baseline. We hypothesized (1) that the treatments would differ in their efficacy for hostility and (2) that olanzapine would be superior to haloperidol. Our primary statistical analysis tested the null hypothesis of no difference among the treatment groups in change in hostility over time. Secondary analysis addressed the question of whether the effects on hostility found in the primary analysis were specific to this item. All our analyses were post hoc. The primary analysis of hostility indicated an effect of differences between treatments (F(4,889) = 4.02, P = .0031). Post hoc treatment-group contrasts for hostility change showed that, at months 1 and 3, olanzapine was significantly superior (P <.05) to haloperidol, quetiapine, and amisulpride in reducing hostility. Secondary analyses demonstrated that these results were at least partly specific to hostility. Both hypotheses were supported. Olanzapine appears to be a superior treatment for hostility in early phases of therapy for first-episode schizophrenia, schizoaffective disorder, and schizophreniform disorder. This efficacy advantage of olanzapine must be weighed against its adverse metabolic effects and propensity to cause weight gain. ISRCTN Register Identifier: ISRCTN6873663

ANOVA; f/p values are listed for main and interactive effects for each ROI.

<p>ANOVA; f/p values are listed for main and interactive effects for each ROI.</p

Abbreviations.

<p>Abbreviations.</p

T1-weighted MRI ROI FIRST masks.

<p>T1-weighted MRI ROI FIRST masks.</p

ROI mean volumes for each group.

<p>Vertical error bars indicate standard error of the mean.</p

Adjusted means and standard deviations of the means for ROI.

<p>Adjusted means and standard deviations of the means for ROI.</p