(July 9, 2019) Abnormalities in the choroid plexus, a brain region vital for neurodevelopment and brain protection, was first implicated in schizophrenia and bipolar disorder in the 1920s. However, the role of this important brain region in psychotic disorders has remained relatively unaddressed since that time.
Though new research published online last month in The American Journal of Psychiatry suggests that the choroid plexus is enlarged in people with psychotic disorders, providing further evidence for the potential role of this region in the development of severe mental illness.
Choroid plexus
There are four choroid plexuses in the human brain, located in each of the ventricles, each of which is a group of brain cells that surrounds core blood vessels that bring nutrients and cellular signals from the rest of the body. These regions are an integral part of the blood-brain barrier, protecting the brain from harmful substances in the rest of the body transported in the blood from reaching the brain.
Both functions of the choroid plexus are important in brain inflammation, as it is involved in transporting inflammatory signals from the blood to the brain as well as controlling inflammatory markers in the CSF. In fact, the choroid plexus is considered the mediator of immune signals from the rest of the body to the brain.In addition, the choroid plexus is responsible for producing cerebral spinal fluid (CSF), the protective fluid that is distributed throughout the brain via the ventricles. CSF also surrounds the brain, providing a cushion for the soft brain tissue within the rigid bone structure of our skull.
Study results
Comparing choroid plexus volumes via structural MRI brain scans, the study authors found that the size of these regions in individuals with psychosis were significantly larger than in those of their first-degree relatives or healthy subjects. In individuals with psychosis, a larger choroid plexus is correlated with smaller grey matter volume, less neural connectivity and lower scores on cognitive tests, according to the results.
Interestingly, individuals with psychosis and larger choroid plexus volumes also had higher levels of Interleukin-6, an immune system signaling molecule previously been shown to be involved in the development of severe mental illness. These results are consistent with Treatment Advocacy Center founder Dr. E. Fuller Torrey’s previous work researching the role of inflammation and the immune response in the development of schizophrenia. Recently, Dr. Torrey has called for more attention to be paid and research funding from the National Institute of Mental Health on these topics. A summary of his most recent paper can be found here.
References:
Elizabeth Sinclair
Director of Research
Treatment Advocacy Center