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Analysis finds link between neuroinflammation, psychosis, schizophrenia

Individuals at ultra-high risk for psychosis and those with schizophrenia exhibited increased microglial activity compared with healthy controls, suggesting a link between neuroinflammation and psychosis.

“While the pathoetiology of schizophrenia is not fully understood, there is increasing evidence for the involvement of neuroinflammatory processes. Microglia are the resident immune cells of the [central nervous system], and several lines of evidence indicate microglial involvement in the pathology of psychosis,” Peter S. Bloomfield, MSc, of Imperial College London, and colleagues wrote.

Researchers used second-generation radioligand [¹¹C]PBR28 and positron emission tomography (PET) imaging to assess whether microglial activity is increased in unmedicated individuals at ultra-high risk for psychosis or those with schizophrenia after controlling for the rs6971 polymorphism in the gene encoding the 18kD translocator-protein. The primary outcome was total gray matter [¹¹C]PBR28 binding ratio which represented microglial activity.

Compared with matched comparison controls, [¹¹C]PBR28 binding ratio in gray matter was increased among individuals at ultra-high risk for psychosis and positively correlated with symptom severity.

Individuals with schizophrenia also exhibited increased microglial activity compared with controls.

“Here we provide, to our knowledge, the first evidence of elevated brain microglial activity in people at ultra-high risk of psychosis and show that greater microglial activity is associated with greater symptom severity. We also demonstrate the first in vivo elevations of [18kD translocator-protein] binding in schizophrenia with a second-generation tracer after adjusting for [18kD translocator-protein] genotyping,” Bloomfield and colleagues wrote.  – by Amanda Oldt

Disclosure: Bloomfield reports conducting research funded by the Medical Research

Council (United Kingdom), the National Institute of Health Research (United Kingdom) and the British Medical Association. Please see the full study for a list of all authors’ relevant financial disclosures.