A blood test could determine which patients are at high risk of developing schizophrenia and other forms of psychosis, paving the way for earlier treatment and better outcomes.

Early intervention is associated with better clinical outcomes in persons with schizophrenia, and treatment during the prodromal phase of illness could prevent the development of a psychotic disorder and thus reduce risk of chronic symptoms and disability.

Scientists at the University of North Carolina (Chapel Hill, NC, USA) analyzed blood samples of 32 patients with symptoms that suggested a high risk for psychosis, alongside blood samples of 35 control subjects. The team was looking for abnormal levels of markers of inflammation, oxidative stress, metabolism and hormones. All participants were clinically assessed every six months and were followed for up to two years.

Samples were analyzed with the Human Discovery Map assay (Luminex; Austin, TX, USA), a bead-based multiplex immunoassay that included 185 analytes involved in hormonal responses, inflammation, growth, oxidative stress, and metabolism. The team found that among the 32 patients at high risk of psychosis, they were accurately able to identify those who went on to develop psychosis through the presence of 15 specific markers, or analytes, in their blood. Of these patients, 14 had schizophrenia, 13 had unspecified psychosis, 2 had major depression with psychotic features, 1 had bipolar disorder, 1 had schizoaffective disorder, and 1 had delusional disorder.

Most of the analytes included in the 15-analyte index are immunomodulatory: as cytokines (interleukin-1B, growth hormone, KIT ligand, interleukin-8, interleukin-7, resistin, chemokine [c-c motif] ligand 8) or as proteins involved in modulating inflammation including blood-brain barrier integrity (matrix metalloproteinase-7, immunoglobulin E, and coagulation factor VII). Three of the analytes, thyroid stimulating hormone, growth hormone, and cortisol are part of hypothalamic-pituitary axes. Interestingly, five of the included cytokines (interleukin-1B, interleukin-7, interleukin-8, KIT ligand, and resistin) are known to regulate hypothalamic-pituitary axes.

Diana O. Perkins, MD, MPH, professor of psychiatry and corresponding author of the study, said, “The blood test included a selection of 15 measures of immune and hormonal system imbalances as well as evidence of oxidative stress. While further research is required before this blood test could be clinically available, these results provide evidence regarding the fundamental nature of schizophrenia, and point towards novel pathways that could be targets for preventative interventions.” The study was published on August 6, 2014, in the journal Schizophrenia Bulletin.

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