A recent study published in JAMA Psychiatry reveals that neuromelanin-sensitive magnetic resonance imaging (NM-MRI) contrast is linked to the severity of psychosis in antipsychotic-free individuals with schizophrenia. The research, conducted by the team at Columbia University led by Kenneth Wengler, Ph.D., delved into the relationship between NM-MRI and psychosis severity in a cross-sectional study.
The study included 42 antipsychotic-free patients with schizophrenia, 53 antipsychotic-free individuals at clinical high risk for psychosis (CHR), and 52 matched healthy controls. The goal was to replicate earlier findings that demonstrated a connection between NM-MRI and psychosis severity by using NM-MRI as a proxy measure of dopamine function. An additional validation sample of 16 antipsychotic-naive patients with schizophrenia was also included.
The researchers uncovered a significant correlation between higher positive total scores on the Positive and Negative Syndrome Scale and increased mean NM-MRI contrast in the regions of interest associated with psychosis in the schizophrenia sample. However, there was no substantial association between higher positive total scores on the Structured Interview for Psychosis-Risk Syndromes and NM-MRI contrast in the CHR sample.
The study’s findings were consistent during the held-out test data, with the 10-fold cross-validated prediction accuracy of psychosis severity exceeding chance. External validation also demonstrated prediction accuracy above chance.
While the authors successfully replicated the association between NM-MRI contrast and psychosis severity in antipsychotic-free individuals with schizophrenia, they were unable to establish the same connection in individuals at clinical high risk for psychosis. This discrepancy highlights the complexity of psychosis and suggests that NM-MRI contrast may serve as a valuable biomarker for assessing and understanding the severity of psychosis in antipsychotic-free patients with schizophrenia.
1. What is Neuromelanin-Sensitive MRI Contrast?
Neuromelanin-sensitive magnetic resonance imaging (NM-MRI) is a specialized imaging technique that allows researchers to visualize and measure the distribution and concentration of neuromelanin in the brain. Neuromelanin is a pigment found in certain brain regions, particularly those associated with dopamine production.
2. How is psychosis severity assessed in the study?
Psychosis severity is assessed using standardized rating scales, including the Positive and Negative Syndrome Scale (PANSS) and the Structured Interview for Psychosis-Risk Syndromes (SIPS). These scales evaluate various symptoms and their severity to provide a quantitative measure of psychosis.
3. What is the significance of this study’s findings?
The study’s findings suggest that NM-MRI contrast could serve as a valuable biomarker for assessing the severity of psychosis in patients with schizophrenia who are not currently being treated with antipsychotic medications. This could aid in understanding the underlying mechanisms of psychosis and potentially guide personalized treatment approaches in the future. However, further research is needed to fully validate and understand the clinical implications of these findings.
Kenneth Wengler et al, Generalizability and Out-of-Sample Predictive Ability of Associations Between Neuromelanin-Sensitive Magnetic Resonance Imaging and Psychosis in Antipsychotic-Free Individuals, JAMA Psychiatry (2023). doi.org/10.1001/jamapsychiatry.2023.4305