The immune system is made up of organs, cells and proteins and is the body’s defense 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 starts to remove synapses, or brain connections, that are inactive or no longer needed.

​

Research conducted on mice, has found that the complement cascade is involved with synaptic pruning. However, there is limited research in this area in a human population.

​

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 processes 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.

​

The objective of the PIPs Study is to examine whether elements of the immune system are linked to neuroimaging indices of synaptic pruning and the symptoms of schizophrenia.