Fifty percent of people with a mental illness actually have more than one mental illness. This statistic has led scientists to research this phenomenon and try to determine if there are common risk factors or physical traits that can be identified in this population, which could allow earlier diagnosis and treatment.
Duke University conducted a study on the “comorbidity of mental illnesses” (the simultaneous presence of two or more illnesses occurring in a patient), and the results are documented in the April 11, 2017 journal of Molecular Psychiatry. Using personal interviews and brain scans of over a thousand Duke undergraduates, research showed those with mental illness comorbidity consistently show differences in their cerebellums, aka “little brain” and in the pons, which are the structures that are used to help one coordinate complex movements. Researchers are hoping this information will begin to help them determine what ultimately causes mental health disorders.
What they discovered through analyzing MRI scans of subjects with comorbidity was a significant correlation between disease and grey matter volume in the cerebellum and white matter pathways throughout the brain. The greater the number of mental illnesses, the lower the grey matter volume in the cerebellum. This was surprising because traditionally the cerebellum has been viewed more related to motor function and coordination, not necessarily emotion and thinking.
Further, the correlation with white matter pathways in the brain showed less integrity with white matter pathways within the pons; meaning the wiring that connects the cerebellum to the reasoning and problem solving portion of the brain, the prefrontal cortex, is also diminished in the group with more mental illnesses. These pathways, which provide feedback to enable us to know how well our physical movements are helping us achieve our goals, so we can change our movements, as necessary, also, most likely provide feedback that helps us regulate our thoughts and emotions.
This suggests that those with less gray matter and less white matter pathways may have poorer communication within the brain. Therefore, actions, physical and verbal, are not receiving feedback in the same way as those with better internal brain communication, resulting in mental health problems.
Further research in different and more academically diverse populations is underway, noting the Duke students in the initial research are, on the whole, healthier and more intelligent than a random population. If the findings are the same, that will be significant and will initiate more studies to better identify and understand the neural bases of psychological problems.