EXPERT REACTION: Could our immune system be contributing to schizophrenia?

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New Australian research suggests that some people with schizophrenia have an increase in white blood cells in their brain. White blood cells are an important part of the immune system and the authors believe that this could signal a key role for inflammation in schizophrenia. Schizophrenia effects 1 per cent of the population in Australia and no single cause has been found to date.

Journal/conference: Molecular Psychiatry

DOI: 10.1038/s41380-018-0235-x

Organisation/s: The University of New South Wales, The University of Adelaide, Neuroscience Research Australia

Funder: NSW Ministry of Health (Office of Health and Medical Research). National Health and Medical Research Council

Media release


In one of the biggest breakthroughs in schizophrenia research in recent times, Professor Cynthia Shannon Weickert at Neuroscience Research Australia (NeuRA) has identified immune cells in greater amounts in the brains of some people with schizophrenia. The study published today in Molecular Psychiatry has the potential to transform global schizophrenia research and open new avenues for developing targeted immune cell therapies.

One in every 100 Australians lives with schizophrenia. No single cause of schizophrenia has been identified, and this has prevented the development of a cure. The current treatments for schizophrenia are designed to suppress symptoms rather than target underlying causes of the disorder. These drugs only partially relieve symptoms and can produce unwanted side effects.
To recognise the significance of this discovery Professor Shannon Weickert says you first need to understand most scientists have had a long held belief that immune cells were independent from the brain pathology in psychotic illnesses.

“In our study, we challenged this assumption that immune cells were independent of the brain in psychiatric illness and made an exciting discovery. We identified immune cells as a new player in the brain pathology of schizophrenia,” said Professor Shannon Weickert.

Current schizophrenia research has focused on the status of three brain cells: the neurons; the glial cells, which support the neurons; and the endothelial cells, which coat the blood vessels. Employing new molecular techniques allowed Professor Shannon Weickert and her team to identify the presence of a fourth cell, the macrophage, a type of immune cell in the brain tissue of people with schizophrenia who show high levels of inflammation.

Professor Shannon Weickert said immune cells have previously been ignored as they had long been viewed simply as travelers just thought to be passing by, undertaking surveillance work. They have never been a suspect until now.

“To find immune cells along the blood brain barrier in increased amounts in people with schizophrenia is an exciting discovery. It suggests immune cells themselves may be producing these inflammatory signals in the brains of people living with schizophrenia,” said Professor Shannon Weickert.

“We have observed in people with schizophrenia, the glial cells, one of the local residents, become inflamed and produce distress signals which change the status of the endothelial cells.

“We think this may cause the endothelial cells to extend sticky tentacles, so when the immune cells travel by some are captured. These cells may transmigrate across the blood brain barrier entering the brain in greater amounts in some people with schizophrenia compared to people without the disorder.”

This discovery shows that specific immune cells are in the brains of some people with schizophrenia in close enough proximity to the neurons to do damage.

Professor Peter Schofield, CEO of NeuRA said this innovative new research has the ability to alter the way in which we may be able to diagnose and treat schizophrenia.

"This breakthrough demonstrates the value of the NSW Government's support for Professor Shannon Weickert as NSW Chair of Schizophrenia Research, which has delivered new insights that the community seeks," said Professor Schofield.

Professor Shannon Weickert is encouraging a cross-collaborative approach between neuroscientists and immunologists globally, to work together to develop treatments targeting this abnormal immune pathology of schizophrenia.

"This opens whole new avenues for therapy, because it suggests that the pathology of schizophrenia could be within the immune cells and the immune cells could be contributing to the symptoms of schizophrenia,” said Professor Shannon Weickert.

Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Professor Anthony J. Hannan is a NHMRC Principal Research Fellow from The Florey Institute of Neuroscience and Mental Health, University of Melbourne and Melbourne Brain Centre

This study adds to our understanding of the link between the nervous system and the immune system in schizophrenia, a brain disorder which strikes sufferers at a young age and has one of the highest burdens of disease. Like any good scientific study, it raises a number of interesting questions.  Firstly, it would be interesting to know how the genetics of these schizophrenia patients contributed to their immune system changes, and how environmental factors may have also played a role.  Secondly, it would be of great interest to examine the immune system of those with ‘first-episode psychosis’ (prior to receiving any schizophrenia treatments such as antipsychotic medications) and those who are ‘ultra-high risk’ for schizophrenia (but have not yet developed symptoms). 

Whilst antipsychotic drugs might contribute to the changes observed in chronically ill schizophrenia patients, other lifestyle changes (including stress, diet, physical activity, sleep and the use of both legal and illicit substances) could contribute to the immune changes observed in these patients. It will be of great interest to assess whether positive lifestyle interventions in patients, and those at ultra-high risk, have beneficial effects on the immune system, and whether this can improve symptoms or prevent onset of this devastating brain disorder.

Last updated: 13 Sep 2018 3:59pm
Declared conflicts of interest:
None declared.

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