Proteins of the Immune System in Psychosis (PIPs) Study
A research study conducted through the Translational Neurobiology Group, with collaborations through Melbourne Health and the Florey Institute of Neuroscience and Mental Health
Schizophrenia is a serious mental illness that affects roughly 1% of the population. It may cause people to see, hear, taste or believe things that are not real. Schizophrenia typically appears during adolescence and young adulthood, but later onset is possible. Living with schizophrenia can be extremely difficult, especially if it goes untreated. The cause of schizophrenia is still unknown.
The immune system is made up of organs, cells and proteins and is the body's defence against infections which help keep us healthy. A part of the immune system in the brain, specifically called the complement cascade, has recently been linked to an increased risk of schizophrenia. THis is because the complement cascade may be involved in a process called synaptic pruning. Synaptic pruning is where the brain starets to remove synapses, or brain connections, that are inactive or no longer needed.
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Research conducted on mice has found that the complement cascade is involved with synaptic pruning. Howver, there is limited research in this area in a human population.
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Studies with humans have found that if too much synaptic pruning does happen, especially during developmental years, then the brain may have more grey matter loss, meaning the brain may not be able to process and store information correctly. This could explain the symptoms that people with schizophrenia experience, such as hearing voices or seeing things that are not there. So far, people with schizophrenia have shown higher levels of complement cascade proteins within their blood and more grey matter loss compared to people without schizophrenia.
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The objective of the PIPs Study was to examine whether elements of the immune system are linked to neuroimaging indices of synaptic pruning and the symptoms of schizophrenia.
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Participants completed online surveys, clinical and cognitive assessments, a blood test and an MRI brain scan as part of the main study participation. An optional sub-study component involved participants consenting to a lumbar puncture procedure at the Royal Melbourne Hospital.
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At recruitment finalisation in 2024, 89 participants completed the main study, of which 30 participants completed the additional sub-study.