Biomarkers of ANTidepressant RESponse and Development Risk of Bipolar Disorder

One in five people will present a major depressive episode (MDE) in their lifetime. While antidepressants (ADs) are currently the standard treatment for MDE, the first AD prescribed is effective in less than 40% of patients and a complete clinical response is only observed after several weeks. Identifying early biomarkers of the response to treatment with an AD could allow the clinician to rapidly identify patients in whom treatment will not be effective and therefore modify patient care. We have recently shown that the messenger RNA (mRNA) of two proteins, ELK1 and GPR56, were present in different amounts in the blood cells of "responder" compared to those of "non-respondent" patients. In this context, our main objective will be to determine whether ELK1 and GPR56 mRNAs, are very early biomarkers of the response to AD, i.e., biomarkers whose variation precedes the clinical response by several weeks. Secondary objectives will be to identify early phase changes in neurophysiological measures, cognitive and behavioral tasks, as well as levels of blood coding and non-coding RNAs, serum cytokine, mitochondrial and metabolic markers, neuroimaging markers as biomarkers of differential treatment outcomes to antidepressant treatment. Patients will be treated with SERTRALINE or FLUOXETINE or DULOXETINE or MAPROTILINE (in monotherapy) with or without adjunct benzodiazepine. Patients are identified as responders or non-responders based on their clinical assessment at 8 weeks after treatment onset. In addition, a second stage will collect data to address another important issue for the management of patients with a MDE: to discriminate those with a major depressive disorder (MDD) from those with a bipolar disorder (BD). BD diagnosis is one of the most common reasons of failure to response to ADs. Therefore, one of our secondary objectives will be to identify biomarkers to differentiate between these two categories of patients. To do this, we will follow patients for a period