Mapping Inter-Individual Heterogeneity in Psychosis and Severe Violence

Brisbane Convention & Exhibition Centre 

Neuroimaging research has revealed brain morphological abnormalities associated with violence and psychosis, however individual differences are substantial and results are not consistent across studies. Recently developed normative modeling of brain MRI features provides a possibility to parse this heterogeneity by mapping inter-individual brain characteristics, whose potential has not yet been explored in forensic psychiatry.
We explored brain heterogeneity in individuals with a history of severe violence with or without a schizophrenia spectrum disorder, non-violent patients with schizophrenia spectrum disorders, and healthy non-violent controls. We utilized lifetime normative trajectories of cortical thickness, surface area, subcortical volumes, and cerebellar volumes. We applied two large-scale publicly available normative models: Destrieux and subcortical atlas-derived regions of interest from 58,836 individuals, and cerebellum normative models based on 27,000 individuals without diagnostic conditions across the lifespan (ages 2-100).
Across groups, we found an overall heterogeneous pattern of individual-level deviations, with a significantly higher frequency of extreme negative deviations in persons with a history of severe violence with or without a schizophrenia spectrum disorder (p = .020, Cohen’s d = .31) and non-violent patients with schizophrenia spectrum disorders (p = .019, d =. 48). Differences were mostly present in subcortical volumes and cortical area, but not thickness, with significant regional group-level differences within the subcallosal and insular cortices, and the cerebellum. Specifically, we found decreased grey matter volumes in the posterior cerebellar hemispheres and the vermal regions in persons with schizophrenia with or without violence history, but with a different subregional pattern.

By applying normative modeling and novel analytical tools, this proof-of-concept study demonstrates the heterogeneous pattern of brain morphometry deviations associated with violence and psychosis. The converging results from group-comparisons and normative modeling analyses illustrate different patterns of cerebellar subregion volume reductions associated with violence in individuals with or without schizophrenia spectrum disorders. These complementary methodological approaches may contribute to improved understanding of the complex underpinnings of violence in forensic psychiatry and warrant further replication.