The study aims to evaluate the contribution of a multi-targeted microbiotherapy at 12 weeks in depressed-patients in a situation of failure of a 1st line of antidepressant treatment and treated in add-on with a 2nd antidepressant, venlafaxine.

Depression is the most common psychiatric illness and has major personal, societal and economic consequences.

Increase in the disease prevalence is significantly associated with certain somatic pathologies, including metabolic diseases and functional intestinal disorders. From a therapeutic point of view, approximately 2/3 patients are not in remission after first-line antidepressant treatment. Moreover, 20 to 30% patients resist at all the therapeutic strategies classically proposed in this indication.

The identification of new therapeutic strategies is therefore a major challenge, especially for patients with chronic depression resistant to standard treatments.

Various research studies have shown the involvement of inflammatory mechanisms in depression. Thus, the increase in the disease prevalence is significantly associated with certain somatic pathologies, in particular metabolic diseases, a certain number of which are linked to abnormalities of the intestinal microbiota. In this context, the use of probiotics is interesting because some have antidepressant effects, anti-inflammatory and metabolic properties. However, even if a few studies have shown an antidepressant effect of probiotics with improvement of biological markers of inflammation, it seems that the use of probiotics alone is not sufficient for lasting results on depressive symptoms.

The PROMOOD clinical research project fits into this context. We propose to carry out a multicenter clinical study with the product developed by GYNOV (GynMDD® multitarget compound with 3 active ingredients: an amino acid (L-glutamine), an ingredient purified from a plant extract (Cavacurmine) and a probiotic (Lactobacillus rhamnosus GG). In a preclinical study carried out at the CNRS on 144 mice, a synergy of action between these 3 ingredients was demonstrated on the anxio-depressive systems, resulting in an improvement far greater than the expected effect of composition and comparable to a reference injectable antidepressant (clomipramine).

In theses context, the microbiotherapy proposed in this project is very original because:

• a multi-target approach targeting several mechanisms of action: intestinal permeability, glutamine/glutamate/GABA cycle, insulin resistance, immunomodulation, oxidative stress;
• prospect of an optimization/simplification of care;
• It is very acceptable for patients both from the point of view of tolerance and from the economic point of view.

With a phase II, prospective, multicenter design, this study aims to evaluate the contribution and the tolerance of a multi-targeted microbiotherapy in addition to venlafaxine, in a second-line antidepressant treatment. The treatment will be delivered during 12 weeks.

Baseline measures will be compared to those obtained during the treatement administration (every week) and after the treatment administration (every week for the next 12 weeks).

Inclusion Criteria:

• Diagnosis of unipolar MDD (Diagnostic and Statistical Manual of Mental Disorders V [DSM-V], QIDS-C16≥15)
• No response at a first antidepressant
• under venlafaxine
• Signed informed consent form
• Subjects affiliated to or beneficiary from a French social security regime

Exclusion Criteria:

• Contraindications to probiotic administration
• Allergy to one of the compounds of the multi-target probiotic or the placebo
• consuming probiotic-based dietary supplements
• Patient with other psychiatric disorders, except social anxiety disorder, generalized anxiety disorder and nicotine use disorder
• Patient with a serious and/or progressive medical condition, including chronic inflammatory pathologies or autoimmune diseases requiring long-term anti-inflammatory treatment (including corticosteroid therapy) or immunosuppressant.
• Patient with a recent infectious episode likely to require antibiotic therapy.
• Patient presenting with a suicidal risk assessed by the suicide item of the QIDS-C16 scale (score item 12 of the QIDS-C16 >2)
• Other concomitant antidepressant and/or lithium and/or anti-inflammatory treatment for the duration of the study
• Subject under measure of protection or guardianship of justice
• Subject beneficiary from a legal protection regime
• Subject unlikely to cooperate or low cooperation stated by investigator
• Subject not covered by social security
• Pregnant woman
• Subject being in the exclusion period of another study or provided for by the "National Volunteer File