Raoul Belzeaux: A Seamless Blend of Two Disciplines

Straddling the fields of psychiatry and molecular biology, Raoul Belzeaux, a professor and psychiatrist at Montpellier University Hospital, focuses on biomarkers of mental disorders. The researcher has just received the Marcel Dassault Prize for his project on rapid testing for bipolar disorder.

Detecting bipolar disorder with a blood test. This is the test being developed by Raoul Belzeaux, a psychiatrist at Montpellier University Hospital, for which he was awarded the Marcel Dassault Prize on October 13, 2022. If the test’s effectiveness is confirmed by a clinical trial, it will help improve the management of this mental disorder, which is still frequently misdiagnosed. According to the French National Authority for Health, it currently takes an average of ten years from the first symptoms to a medical diagnosis.“A general practitioner can easily diagnose depression in a patient, but it can be a symptom of various conditions. However, treatments differ for depression and bipolar disorder. Taking antidepressants can even worsen symptoms in a patient with bipolar disorder,”explains Raoul Belzeaux. The diagnosis is based on measuring cytokine levels in the blood, an inflammatory biomarker that exhibits specific characteristics in patients with bipolar disorder (BD). BD is a cyclical mood disorder characterized by depressive episodes and manic episodes.

Precision medicine

Raoul Belzeaux has been combining psychiatry with molecular markers since his medical school days. During his residency in psychiatry, he decided to pursue a master’s degree in molecular biology. During his doctoral research, he focused on the messenger RNA signature in depressive episodes—in other words, how gene expression, as measured by mRNA, varies during the diagnosis and treatment of depression. His findings, presented in 2011, confirmed in particular that the expected variation in the brain is also found in the blood. “Today, this is an accepted fact, but the discovery of this biomarker in the blood was important for medical practice because it facilitates diagnosis,” the specialist emphasizes.

From 2015 to 2017, he joined Dr. Gustavo Turecki’s team at McGill University in Montreal for a postdoctoral fellowship; Turecki is“a leader in epigenetic research on mood disorders and suicide,” he notes.  This provided an opportunity to identify a new biomarker, the GPR56 receptor, involved in the regulation of depression. Riding the wave of precision medicine and early diagnosis, Raoul Belzeaux thus became a specialist in identifying mood disorders through blood biomarkers. Since 2011, the researcher has also been part of the FondaMentale foundation, dedicated to the development of precision medicine in psychiatry.

600 patients over a two-year period

In his latest research on TB, the challenge is therefore to find a biomarker that is easy to test.“Cytokines—proteins involved in communication between immune system cells and beyond—were a good candidate, since the tools to measure them are already widely available,” explains the researcher. The hypothesis was validated and recognized this year. But to confirm the test’s value, it must still demonstrate its superiority over existing diagnostic tools.“The questionnaire currently used by general practitioners has a sensitivity of about 43%; the blood test will need to achieve an efficacy of over 75% to justify its industrial development,” emphasizes Raoul Belzeaux, who also acknowledges that cytokines are a sign of an inflammatory state that can have multiple causes. The test is therefore only applicable after a doctor has diagnosed depression: it then serves only to distinguish depression from bipolar disorder. The researcher thus points out that a biomarker is a trace, an indicator of the patient’s condition.“Biomarker-based tests should be viewed as tools available to practitioners and not as a substitute for their work,” the psychiatrist insists.

The €90,000 from the Dassault Prize will contribute to the €550,000 budget needed to conduct the clinical trial involving 600 patients over a two-year period. Following that, if the test is validated, the long road to commercialization will begin, with plans to create a startup in partnership with SATT Sud-Est, a company responsible for transferring technologies from laboratories into industrial applications.