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Multivariate analyses reveal link between brain variance, psychosis

Multivariate analyses using nonimaging and neuroimaging delivered a more accurate characterization of the link between brain variations and psychosis, demonstrating that general intelligence, BMI, positive psychotic symptoms, substance use and antipsychotic medication contributed to differences in brain structure and function, according to study findings.

“[Prior] findings have led to calls for caution in ascribing case-control differences in neuroimaging measures to psychosis-related mechanisms and for integrated analyses of multimodal imaging as well as clinical and behavioral variables,” Dominik A. Moser, PhD, department of psychiatry, Icahn School of Medicine at Mount Sinai, and colleagues wrote in JAMA Psychiatry. “There is a notable paucity of multivariate approaches that address this issue despite increased interest in diagnostic classification and patient stratification based on neuroimaging data.”

Researchers conducted an imaging study using an integrated multivariate approach to better describe the relationship between neuroimaging measures and behavioral, health and demographic variables in patients with psychosis.

Moser and colleagues obtained high-resolution, multimodal MRI data from 92 patients with schizophrenia, 37 with bipolar disorder and 48 volunteers without psychosis, then calculated cortical thickness, subcortical volumes, white matter integrity, brain activation during tasks and resting-state functional connectivity. Researchers examined nonimaging measures, including clinical features, cognition, substance use, psychological trauma, physical activity and BMI, in all participants.

The imaging and nonimaging data sets significantly correlated (P < .001). Whether a participant had psychosis did not change the link between imaging phenotypes and nonimaging factors that influence MRI signals. Analysis of nonimaging variables revealed that age, intelligence and BMI correlated with multiple imaging phenotypes; cannabis use and other substance use to the subcortical volume variate; and alcohol use to white matter integrity.

Researchers observed positive psychosis symptoms in the multivariate global, cortical thickness and brain activation models, but negative symptoms mostly correlated with measures of subcortical volume. They also observed negative associations between positive symptoms and the multimodal, cortical thickness and task-related brain activation variates. Depression/anxiety symptoms correlated with the white matter variate. Antipsychotic medication dosage negatively related with the global and cortical thickness variates.

“The results suggest that the severity of positive symptoms, arguably the hallmark of psychosis, is likely to be meaningfully related to reductions in cortical thickness and brain activation even when other nonimaging factors are also modeled,” Moser and colleagues wrote. “In addition, IQ and BMI had significant contributions to neuroimaging findings; because both measures are easy to obtain, their routine inclusion in neuroimaging studies is both feasible and advisable.” – by Savannah Demko

Disclosures: The authors report no relevant financial disclosures.