Unipolar major depressive disorder is the leading cause of disability worldwide. The most commonly used treatments for major depressive episodes (MDE) are antidepressant medications. However, they have limited efficacy and their onset of action is long, ranging between 2 to 6 weeks. During this period, hospitalization can become necessary, especially for severe MDE. It is crucial to improve the early effectiveness of treatments for these patients in order to alleviate their suffering, limit complications (suicidal risk), and reduce hospitalization durations (approximately 1000 euros per day). The efficacy of intravenous ketamine has been demonstrated in pharmaco-resistant depression but remains to be proven in non-pharmaco-resistant severe MDE. Additionally, PET imaging using \[11C\]UCB-J, which allows the in vivo study of synaptic density in the human brain, has shown significant decreases in synaptic density in unipolar patients with severe MDE. Furthermore, a single ketamine infusion was found to enhance synaptogenesis
Current MDE in the context of unipolar major depressive disorder (DSM-5 criteria), hospitalized (open care) for this episode, with a minimum HDRS score of 24 and in the context of an indication for the introduction of venlafaxine treatment.
Patient aged between 18 and 65.
Signed free and informed consent
Membership of a social security scheme
Criteria relating to associated pathologies entailing particular risks: pharmaco-resistant CDE (failure of at least two properly conducted treatments with two different antidepressant treatment classes), CDE with psychotic features, psychotic disorder, bipolar disorder, current (<1 month) substance use disorder (excluding tobacco).
Liver impairment (AST and/or ALT > 3 ULN, PAL and/or GGT and/or bilirubin > 2 ULN).
Severe renal insufficiency (GFR <30ml/min with Cockcroft's formula).
Bradycardia less than 55 beats per minute.