Study uncovers how physical health influences mental health through brain pathways

Multiple biological pathways involving organs and the brain play a key part in physical and mental health, according to a new study published in the journal Nature Mental Health.

It is analyzed that out of 18,000 individuals, 7,749 people had no major clinically diagnosed medical or mental health conditions, while 10,334 had reported a diagnosis of either schizophrenia, bipolar disorder, depression, or anxiety. Using advanced statistical models, the researchers found a significant association between poorer organ health and higher depressive symptoms, and that the brain plays an important role in linking body health and depression.

The organ systems studied included the lungs, muscles and bones, kidneys, liver, heart, and the metabolic and immune systems.

By integrating clinical data, brain imaging, and a wide array of organ-specific biomarkers in a large population-based cohort, for the first time, it established multiple pathways involving the brain as a mediating factor through which poor physical health of body organ systems may lead to poor mental health.

Physical health was also taken into account, as well as lifestyle factors such as sleep quality, diet, exercise, smoking, and alcohol consumption.

Professor Andrew Zalesky, an author of the study from the Departments of Psychiatry and Biomedical Engineering at the University of Melbourne, said. "This is a significant body of work because we have shown the link between physical health and depression and anxiety, and how that is partially influenced by individual changes in brain structure.

It is concluded that maintaining good physical health can positively influence brain function, leading to better mental well-being. Conversely, poor physical health may disrupt these brain pathways, contributing to mental health issues such as anxiety, depression, or cognitive decline. The findings underscored the importance of a holistic approach to health, where physical and mental well-being are closely intertwined, and suggest that interventions aimed at improving physical health could also have beneficial effects on mental health.

References: Tian, Y. E., et al. (2024). Brain, lifestyle and environmental pathways linking physical and mental health. Nature Mental Health. doi.org/10.1038/s44220-024-00303-4.