professionals urge caution
Santé

professionals urge caution

France — SYNLAB and ALCEDIAG announced on March 22 the launch in France of the first blood test to help diagnose mental health and is designed to differentiate between bipolar disorder and depression. This information might seem surprising if we know how difficult it is to diagnose psychiatric pathologies, especially since they share common symptoms such as recurrent depression and bipolar disorder.

So what should we think about this test? Is this the real hope for patients, as the laboratory claims? In the world of psychiatry, reactions are cautious, as areFrench Association of Biological and Neuropsychopharmacological Psychiatry (AFPBN) and from Stefan JaminDirector of Research in Translational Neuropsychiatry (Inserm U955, Mondor Institute for Biomedical Research), interviewed Medscape.

To date, no tests have passed [ces] Conditions for use in clinical practice
AFPBN

The problem of early diagnosis

Depression and bipolar disorder are two different mental illnesses that are treated differently. Making a correct diagnosis at an early stage and providing appropriate treatment is a major challenge for clinicians, especially since poor treatment of bipolar disorder often causes serious consequences for patients’ mental and physical health, as well as quality of life. life and the lives of their loved ones.

However, published studies show that bipolar disorder requires an average of 8 to 10 years to be diagnosed, sometimes much longer if the diagnosis is based on a clinical psychiatric assessment of the patient by a specialist physician using questionnaires and validated rating scales. .

Thus, early and accurate diagnosis of bipolar disorder, allowing appropriate treatment, will be a great achievement for patients and their loved ones. This is what French laboratories SYNLAB are offering in partnership with ALCEDIAG through myEDIT-B, a blood test they describe as “the first validated diagnostic test for differentiating depression and bipolar disorders.”

Will this test attract psychiatrists (the announcement of its availability somewhat surprised the medical and scientific psychiatric community)? Nothing is less certain.

IN press release published onThe French Association of Biological Psychiatry and Neuropharmacology, after this statement, confirmed that “to date, no test corresponds to [ces] conditions for use in clinical practice.” For a diagnostic test to be scientifically valid, ethical and suitable for use in clinical practice, its development must meet strict criteria, recalls the AFPBN, which has about ten of them, such as the fact that the scientific results must be confirmed in at least two independent clinical studies . or cohort, that the sensitivity (detection of true positives) and specificity (detection of false negatives) of the test must be satisfactory, or that the cost of the test must be ethically responsible and ensure patient access, regardless of commercial logic.

This is where the problem lies, as ALCEDIAG reports two clinical studies, but only one study has been published to date. broadcast Psychiatry – out of 400 patients. Which in this case “already had a well-established psychiatric pathology, did not exhibit exactly the same symptoms between people suffering from recurrent depression and people suffering from bipolar disorder, and did not receive the same treatment,” points out geneticist Stéphane Jamin.

If the researcher accepts that the differentiation between bipolar disorder and depression is very important, especially from a treatment point of view, since antidepressants prescribed to a patient with bipolar disorder can lead to a manic turn if they are not accompanied by treatment with mood regulators, he considers that what, given what the laboratory publishes makes it difficult to comment on the test at this time.

RNA editing method

This is especially true since the method on which myEDIT-B is based, which measures RNA editing modifications of specific markers in patients’ blood that can lead to amino acid differences in proteins, is specific to ALCEDIAG. laboratory. This was combined with an artificial intelligence tool that allowed the specific selection of 8 RNA sequences for RNA editing analysis from several thousand edited ones to obtain a differential signature of unipolar and bipolar depressions. “This method is a niche, a trademark of ALCEDIAG,” admits Stéphane Jamin, who nevertheless wonders about the value of measuring this “editing” at the periphery of the central nervous system.

“This technique differs from that adopted by most international consortia very active in this area of ​​research, which compare genomic nucleotide (DNA) differences between individuals in large cohorts of tens of thousands of people. the reasons that are most often repeated in connection with pathology in order to draw a conclusion about the risk of developing a mental illness, the researcher clarifies. “However, the information provided by these very large studies does not currently allow us to determine who is at risk of developing the disease, nor [la plus simple] observing the family recurrence (heritability) of this” puts the researcher into perspective.

Rigorous scientific testing awaited

Although ALCEDIAG boasts a sensitivity and specificity of its test of over 80%, the world of psychiatry remains cautious. asked FranceInfoTV this weekend, Marion LeboyerCEO of the company FondaMentalpsychiatrist and researcher (AP-HP, Inserm, Créteil), like AFPBN and Stéphane Jamin, emphasized an interest in promoting research into mental illness, in particular that which will lead to a better understanding and care of patients with bipolar disorders. , but expressed caution about this test due to the lack of rigorous scientific validation through clinical trials.

Regarding “the ALCEDIAG test and its commercial aspect, caution is required,” concluded Stéphane Jamin. The future will tell whether psychiatrists will prescribe this test for €899, which is not currently reimbursed by social security (see box). ALCEDIAG plans to submit a review file to the FDA.

Price 899 euros – still not reimbursed by social security.

In practice, the test will be available from April 2024 with a doctor’s prescription in the laboratories of the SYNLAB France network. It will target patients aged 18 years and older who are currently being treated for a moderate or severe depressive episode (CDE). The test results are sent within 4 weeks to the prescribing psychiatrist, who will confirm the diagnosis to the patient during a consultation. This quality in vitro (IVD) medical device, already available in Italy, carries the CE-IVD mark. In France, you will still have to pay €899 – which is currently not reimbursed by social security due to a lack of sufficient clinical data – to benefit from this benefit.

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