Descartes’s notion of dualism – that the mind and body are separate entities – is wrong, but has proved surprisingly persistent, and until recently dominated attempts to understand mental illness. When the brain stopped working properly, a psychological origin was sought. Undoubtedly, life’s experiences and our personalities shape the way our brains function. But there is now a compelling body of evidence that brain disorders can also originate from things going awry in our basic biology. Particularly intriguing is the discovery that the brain, once thought to be separated from the immune system by the blood-brain barrier, is powerfully influenced by immune activity.
The latest trial, focused on schizophrenia, is backed by converging evidence from several fields that immune cells in the brain, called microglia, play at least some role in this disease. Prof Oliver Howes, the psychiatrist leading the work, discovered that these cells appear to go into overdrive in the early stages of schizophrenia. Genetics studies have linked changes in immune system genes to increased risk for schizophrenia and anecdotal evidence, including a recent case report of a patient who developed schizophrenia after receiving a bone marrow transplant from a sibling with the illness, also triangulates on to the immune system. “It’s all challenging the idea that the brain is this separate privileged organ,”said Howes.
Schizophrenia is not a special case. Scientists are showing that immune activity may play a role in a broad spectrum of mental disorders, ranging from depression to dementia.
People with diabetes, an auto-immune disease, are 65% more likely to develop dementia, according to a 2015 study. Other research has found that Alzheimer’s patients who suffered regular infections, such as coughs and colds, had a fourfold greater decline in memory tests during a six-month period compared with patients with the lowest infection levels. And there is tentative evidence that some patients with treatment resistant depression may benefit from antibody treatments. Perhaps most striking has been the discovery of an entire network of vessels beneath the skull, linking the brain and the immune system, that had surprisingly been overlooked until very recently.
“It has been a fundamental problem that the brain and mind have been seen as somehow separate entities, and that physical and mental healthcare are separate,” said Belinda Lennox, senior clinical lecturer in psychiatry at the University of Oxford. “It has denied the psychological factors that play a vital part in all medical disorders, just as much as it has denied the importance of the biological factors in mental illness.”
Whether the latest trial will yield a successful treatment is difficult to predict and the psychiatry’s record warns against premature optimism. However, recognising that biological factors, such as the immune system, can have a powerful influence on the brain and sometimes explain why things go wrong, will be essential to finding new and better treatments.
Link to full blog here: https://www.theguardian.com/society/2017/nov/03/recognising-that-mind-and-body-are-not-separate-opens-door-for-new-treatments-schizophrenia