# The potential of neuromelanin-sensitive MRI in psychiatric disorders

## TL;DR

NM-MRI is a promising tool for studying brain systems linked to psychiatric disorders, potentially aiding in understanding and treating conditions like schizophrenia and depression.

## Contribution

This paper reviews the potential of neuromelanin-sensitive MRI in elucidating catecholaminergic system dysregulation in psychiatric disorders.

## Key findings

- NM-MRI reveals alterations in catecholaminergic systems in schizophrenia, substance use disorders, and depression.
- Few studies have explored NM-MRI in anxiety and neurodevelopmental disorders despite their links to dopamine and norepinephrine dysfunction.
- Standardization and longitudinal studies are needed to improve NM-MRI's clinical utility in psychiatry.

## Abstract

Psychiatric disorders represent a significant public health concern due to their high prevalence and lifelong substantial impact. Despite advances in understanding their neurobiological underpinnings, the transdiagnostic mechanisms driving psychiatric conditions remain unclear. Neuromelanin-sensitive magnetic resonance imaging (NM-MRI) is a non-invasive technique for investigating the dopaminergic and noradrenergic systems, offering valuable insights into their role in psychiatric disorders. This review explores the potential of NM-MRI in psychiatric research, considering its promise to reveal links between dopaminergic and noradrenergic dysregulation and psychiatric conditions, thereby offering insights in neurobiological mechanisms. We summarize current NM-MRI findings across psychiatric disorders, including psychosis, mood disorders, and anxiety disorders. Across studies, NM-MRI provides converging evidence for alterations in catecholaminergic systems in several psychiatric conditions, particularly schizophrenia, substance use disorders, and depression. However, the evidence base remains uneven, with relatively few studies concerning anxiety disorders, obsessive compulsive disorder, and neurodevelopmental disorders, despite their known associations with dopaminergic and noradrenergic dysfunction. At present, most NM-MRI findings derive from cross-sectional studies using heterogeneous acquisition and analysis approaches, which limits direct comparability and clinical translation. To fully establish NM-MRI as a clinical research tool in psychiatric context, further efforts are needed to standardize protocols and improve specificity and reliability. Moreover, longitudinal studies and cross-diagnostic comparisons are required to determine whether NM-MRI measures can contribute to risk stratification, treatment monitoring, or other clinically applications. Overall, NM-MRI represents a valuable research tool for probing catecholaminergic involvement in psychiatric disorders and may, with further validation, contribute to future biomarker development in mental health research.