Neuromelanin-sensitive MRI linked to psychosis severity in schizophrenia

Neuromelanin-sensitive magnetic resonance imaging (NM-MRI) contrast is associated with psychosis severity in antipsychotic-free patients with schizophrenia, according to a study published online Nov. 8 in JAMA Psychiatry.

Kenneth Wengler, Ph.D., from Columbia University in New York City, and colleagues conducted a cross-sectional study involving 42 antipsychotic-free patients with schizophrenia, 53 antipsychotic-free individuals at clinical high risk for psychosis (CHR), and 52 matched healthy controls to replicate previous findings relating NM-MRI, a proxy measure of dopamine function, to psychosis severity. Data were also included for an external validation sample of 16 antipsychotic-naive patients with schizophrenia.

The researchers found that higher Positive and Negative Syndrome Scale positive total scores correlated with higher mean NM-MRI contrast in the psychosis regions of interest (ROI) in the schizophrenia sample.

No significant association was found between a higher Structured Interview for Psychosis-Risk Syndromes positive total score and NM-MRI contrast in the psychosis ROI in the CHR sample. In held-out test data, the 10-fold cross-validated prediction accuracy of psychosis severity was above chance; prediction accuracy of external validation was also above chance.

"We provided a direct replication of the in-sample association between NM-MRI contrast and psychosis severity in antipsychotic-free schizophrenia. In turn, we failed to replicate such an association with CHR," the authors write.

Wengler disclosed having filed patents for the analysis and use of NM-MRI in central nervous system disorders.