Raoul Belzeaux, an untroubled bidisciplinarity

Straddling psychiatry and molecular biology, Raoul Belzeaux, PUPH and psychiatrist at Montpellier University Hospital, is interested in biomarkers of mental disorders. He has just been awarded the Marcel Dassault prize for his project to develop a rapid test for bipolar disorders.

Detect 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 psychological disorder, which is still poorly diagnosed. According to the French health authority, the average time between the first symptoms and a medical diagnosis is ten years. " A general practitioner can easily diagnose depression in a patient, but it can be a symptom of a number of different pathologies. Treatments for depression and bipolar disorder are different. Taking antidepressants can even aggravate the disorder in a bipolar patient ," explains Raoul Belzeaux. Diagnosis is based on the measurement of cytokines in the blood, an inflammatory biomarker that is specific to patients with bipolar disorder (BD). Bipolar disorder is a cyclical mood disorder with phases of depression and mania.

Precision medicine

Raoul Belzeaux has been combining psychiatry and molecular markers since his medical studies. During his residency in psychiatry, he decided to take up a master's degree in molecular biology. In his doctorate, he became interested in the signature of messenger RNAs in depressive episodes, in other words, how gene expression - measured through mRNAs - varies during the diagnosis and treatment of depression. His results, backed in 2011, confirm in particular that the variation expected at brain level 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, as it facilitates diagnosis ", stresses the specialist.

Between 2015 and 2017, he joined Dr. Gustavo Turecki's team at McGill University in Montreal, "a leader in epigenetic research into mood disorders and suicide ", for a postdoctorate. The 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 has become a specialist in the identification of mood disorders using blood biomarkers. In 2011, he joined the FondaMentale foundation, dedicated to the development of precision medicine in psychiatry.

600 patients over two years

For his latest TB research, the challenge was to find a biomarker that was easy to test. "Cytokines - proteins involved in communication between immune system cells and beyond - were a good candidate, as the tools for measuring them are already widely available ", explains the researcher. This hypothesis was validated and rewarded this year. But to confirm the test's interest, it still needs to demonstrate its superiority over existing diagnostic tools. " The questionnaire currently used by general practitioners has a sensitivity of around 43%; the blood test will have to achieve an efficacy of over 75% to justify its industrial development ", stresses Raoul Belzeaux, who also recognizes that cytokines are the sign of an inflammatory state, the reasons for which can be multiple. The test is therefore only applicable after a doctor has diagnosed depression: it can then only discriminate between depression and bipolar disorder. The researcher points out that a biomarker is a trace, a clue to the patient's situation. " Biomarker-based tests should be seen as tools available to practitioners, not as substitutes for their work ", insists the psychiatrist.

The €90,000 from the Dassault Prize will add to the €550,000 budget needed to conduct the clinical trial on 600 patients over a two-year period. Following this, if the test is validated, the long road to industrial valorization will begin, with plans to create a startup in conjunction with SATT Sud-Est, a company responsible for transferring technologies from the laboratory to industrial applications.