A team of medical researchers based in the University of Policlinico Hospital in Milan, Italy, claim that they have discovered biomarkers for bipolar patients with and without psychosis. The team’s study, which was published in the journal Bipolar Disorders, found that the brains of both sets of bipolar patients, those with psychosis and those without, metabolized glucose in ways that were distinct from control subjects without bipolar disorder.

Biomarkers have long been used in numerous medical fields. They are, to use the definition created by the International Programme on Chemical Safety, which was led by the World Health Organization, the United Nations, and the International Labor Organization, a biomarker is “any substance, structure, or process that can be measured in the body or its products and influence or predict the incidence of outcome or disease.”

Examples include even basic information like pulse or blood pressure. However, this data gives medical professionals valuable information about what is happening within your body.

Though they are not new, finding biomarkers in the field of mental health has proven elusive. There is currently no set of observable phenomena in the body that indicate that a patient has a specific mental illness with total certainty. Rather, mental health professionals have relied more heavily on self-reporting to diagnose and treat patients with mental illnesses.

This is not for want of trying. Researchers have been looking for them. Unfortunately, they have not been able to find any that reliably correlate with mental illnesses. This is why the study out Milan is such big news.

By using fluorodeoxyglucose (FDG), a tracer that allows researchers to study how glucose is processed by the brain with the aid of a positron emission tomography (PET) scans, they found that glucose uptake with bipolar patients with and without psychosis was different when compared to healthy controls. Furthermore, there were clear distinctions between bipolar patients with and without psychosis.

While the study’s findings may not seem revolutionary, the research reveals that there are observable phenomena in the brain that correlate with symptoms of at least one mental illness. Consequently, this leaves the door open to the possibility that the occurrence of other mental illnesses may also correlate strongly with other biomarkers that doctors could eventually be able to discern.

If this is the case, biomarkers could eventually be used to improve our understanding of the causes of mental illnesses. Furthermore, they may also improve mental health professionals’ ability to diagnose, treat, and perhaps even predict mental illness in the future.