Add-on buprenorphine at analgesic doses for the treatment of severe suicidal ideas during a major depressive episode

INTERVENTION: Product Name: BUPRENORPHINE,Product Code: SUB05985MIG,Pharmaceutical Form: SUBLINGUAL TABLET,Other descriptive name: ,Strength: 0.4mg,Product Name: BUPRENORPHINE,Product Code: SUB05985MIG,Pharmaceutical Form: SUBLINGUAL TABLET,Other descriptive name: ,Strength: 0.4mg,Product Name: lactose monohydrate,Product Code: N/A,Pharmaceutical Form: N/A,Other descriptive name: N/A,Strength: N/A,Pharmaceutical form of the placebo: N/A CONDITION: MedDRA version: 23.0Level: LLTClassification code: 10083288Term: Clinical depressionSystem Organ Class: 10037175 mental disorders ; MedDRA version: 23.0Level: LLTClassification code: 10083288Term: Clinical depressionSystem Organ Class: 10037175 Therapeutic area: Psychiatry and Psychology [F] ‐ Mental Disorders [F03] PRIMARY OUTCOME: Main Objective:To show a significant effect of buprenorphine vs. placebo for the treatment of suicidal ideas at D7, and assess the most effective dosage (0.8mg vs. 0.4mg) of buprenorphine. Primary end point(s):Scores on the Scale for Suicidal Ideation (SSI) at Day 7 for the last 7 days Secondary Objective:To show maintenance of a significant effect of buprenorphine on suicidal ideas from D0 to D42.,To show a significant effect of buprenorphine on psychological pain from D0 to D14 and a mediating effect of psychological pain in the relationship between buprenorphine and suicidal ideas.,To determine the effect of buprenorphine on the depressive syndrome in general (excluding suicidal ideas and psychological pain) from D0 to D14.,To determine the treatment arm with the lowest number of discontinuations for inefficacy according to the patient from D0 to D14.,To determine the number of suicide attempts or completed suicides during follow‐up from D0 to D90.,To determine the dose of buprenorphine with the best tolerance profile from D0 to D14.,To determine the frequency of withdrawal symptoms from D14 to D21 for each dose.,To identify the physiological mechanisms underlying psychological pain and suicidal ideation, the biological mechanisms of response to buprenorphine treatment, and the predictive factors of response to buprenorphine by Neuropsychological processes;,To identify the physiological mechanisms underlying psychological pain and suicidal ideation, the biological mechanisms of response to buprenorphine treatment, and the predictive factors of response to buprenorphine by Brain processes (both structural and functional alterations);,Biochemical processes (epigenetic markers, inflammatory markers, intestinal microbiota). We will create a biobank in anticipation of ancillary studies (additional funding will be sought for these analyses). INCLUSION CRITERIA: The patient is a man or a woman aged at least 18 years old and 65 years old at the most.,The patient is hospitalized,The patient suffers from a current major depressive episode without psychotic features according to DSM‐5 criteria and a Montgomery‐Asberg Depression Rating Scale (MADRS) score > 20, as part of a bipolar or major depressive disorder.,The patient has a current Scale for Suicidal Ideation (SSI) score > 8.,The patient must have given his/her informed and signed consent.,The patient must be insured or beneficiary of a health insurance plan. SECONDARY OUTCOME: Secondary end point(s):3T Magnetic Resonance Imaging measurements Secondary end point(s):Blood and stool samples collection to create a biobank Secondary end point(s):Psychological pain evaluation by a Visual Analog Scale (PPP‐VAS) from D0 to D42 (current and for the last 7 days, except at D2 = for the last 2 days) Secondary end point(s):Reports of side effects Secondary end point(s):Reports of suicide attempts and suicide completion after the treatment phase Secondary end point(s):Reports of the reasons for discontinuing treatment Secondary end point(s):Reports of withdrawal symptoms Secondary end point(s):Score on the SSI from D7 to 42 for the last 7 days (except at D2 = for the last 2 days) Secondary end point(s):Scores at neuropsychological tests Secondary end point(s):Scores at the Beck Depression Inventory (BDI‐II) and Montgomery‐Asberg Depression Rating Scale (MADRS) after excluding the suicidal ideation items, for the last 7 days.