Using Blood Tests to Diagnose Depression and Bipolar Disorder

As written by: Sai Srihaas Potu The Latest Med News, April 16, 2021

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Major depressive disorder and generalized anxiety disorder are among the most commonly diagnosed mental illnesses in the USA. Both are associated with a high societal and economic burden.

Depression is the most prevalent psychiatric disorder worldwide and is the most common mental illness appearing in primary care. According to the World Health Organization (WHO), approximately 350 million people suffer from depression worldwide. As for global morbidity, measured in disability-adjusted life years, depressive episodes increased by 37% between 1990 and 2010. It has been projected that by 2030, it will be the leading cause of disability in developed countries.

Diagnosis is complicated, since it is often based on criteria as opposed to very specific symptoms, which may be difficult to recognize by poorly trained professionals. Furthermore, oftentimes, patients do not seek out health assistance due to social stigma. It is commonly believed that the probability of experiencing a depressive episode increases with certain genetic, cognitive, medical, environmental, and social factors.

While current diagnosis and treatment approaches are largely trial and error, a breakthrough study by Indiana University School of Medicine researchers sheds new light on the biological basis of mood disorders. It offers a promising blood test aimed at a precision medicine approach to treatment.

This new blood test can distinguish the severity of a person’s depression and their risk for developing severe depression at a later point. The test can also determine if a person is at risk for developing bipolar disorder. Researchers say the blood test can also assist in tailoring individual options for therapeutic interventions.

Led by Alexander B. Niculescu, MD, Ph.D., Professor of Psychiatry at IU School of Medicine, the study builds on previous research conducted by Niculescu and his colleagues into blood biomarkers that track suicidality as well as pain, post-traumatic stress disorder, and Alzheimer’s disease.

The researchers believe that blood biomarkers are emerging as important tools in disorders where subjective self-report by an individual, or a clinical impression of a health care professional, is not always reliable. These blood tests can open the door to precise, personalized matching with medications, and objective monitoring of response to treatment.

Blood biomarkers offer real-world clinical practice advantages. The brain cannot be easily biopsied in live individuals, so researchers worked hard over the years to identify blood biomarkers for neuropsychiatric disorders. Given the fact that 1 in 4 people will have a clinical mood disorder episode in their lifetime, the need for and importance of efforts cannot be overstated. It is important that researchers continue to analyze and understand the biomarkers behind depressive episodes as they could be very prevalent during the COVID-19 pandemic.


1. H. Le-Niculescu, K. Roseberry, S.S. Gill, et al. Precision medicine for mood disorders: objective assessment, risk prediction, pharmacogenomics, and repurposed drugs. Molecular Psychiatry. 2021.