Researchers Develop a Blood Test to Diagnose Bipolar Disorder

Earlier this week, researchers at the University of Cambridge reported on metabolomic biomarker signatures for bipolar disorder, comparing them to unipolar depression. In a press release from the university, the investigators postulated that a blood test based on these biomarkers can help minimize the risk of misdiagnosing bipolar disorder (BPD) as major depressive disorder (MDD).  

“People with bipolar disorder will experience periods of low mood and periods of very high mood or mania. But patients will often only see a doctor when they’re experiencing low mood, which is why bipolar disorder frequently gets misdiagnosed as major depressive disorder,” explained Jakub Tomasik, PhD, lead author, and researcher in the Cambridge Department of Chemical Engineering and Biotechnology, in the university’s press release.   

Although the researchers have not fully developed the blood tests, the proof-of-concept study was published in JAMA Psychiatry.  

The diagnostic analysis used data from the United Kingdom’s Delta study, which collected insights from April 27, 2018, to February 6, 2020. Beyond that, the scientists collected online survey data from patients who had an MDD diagnosis within the past five years and were experiencing depressive symptoms between February 2022 and July 2023.  

Through dried blood spots (DBSs), researchers analyzed 17 biomarkers that can help identify BPD in patients dealing with depressive symptoms. Additionally, the combined biomarker analysis with patient-reported information, demographic data, Patient Health Questionnaire-9 scores, and the results of the Mood Disorder Questionnaire.  

According to the researchers, many people with bipolar disorder are misdiagnosed with major depressive disorder due to the nature of their disease.  

“When someone with bipolar disorder is experiencing a period of low mood, to a physician, it can look very similar to someone with major depressive disorder,” added Sabine Bahn, MD, PhD. “However, the two conditions need to be treated differently: if someone with bipolar disorder is prescribed antidepressants without the addition of a mood stabilizer, it can trigger a manic episode.” 

Overall, the researcher found that a combined diagnostic approach, including biomarker tests and patient-reported information, significantly improved clinician’s diagnostic accuracy for BPD.