Comparison of Esketamine Nasal Spray vs.Aripiprazole in Treat.Resistant Major Depressive Disorder in Elderly Patients

Inclusion Criteria: * Patients between 60-74 years * To be receiving antidepressant treatment that includes an antidepressant at the time of screening that is not responding (less than 25% improvement in symptoms) after receiving an adequate dose \[or local equivalent, if applicable\] for at least 6 weeks and have been increased to the dose maximum allowed * Current antidepressant treatment must have been immediately preceded by failure to respond to at least 3, but not more than 5, different consecutive treatments (all within the same moderately severe depressive episode) with antidepressant drugs (AD) taken at an appropriate dose for at least least 6 weeks (3 antidepressant failures including the current one) * To have been treated with at least 3 different classes of antidepressants between treatments taken at appropriate doses for at least 6 weeks without response in the current moderate to severe depressive episode (including current treatment with an antidepressant) * To be taking a single oral antidepressant on day 1 before randomization * Participants who, at the time of screening, are taking a combination of antidepressants and/or rescue treatment (other than aripiprazole) for the current moderate to severe depressive episode may participate in the study. Exclusion Criteria: * Treatment with drugs contraindicated with the use of esketamine and aripiprazole. * Patients in whom a high risk of suicide is detected at the screening visit, according to the criteria established by Columbia University according to the C-SSRS evaluation * Patients who are participating in another clinical trial with active treatment * Patients who do not have the capacity to consent to participation in the trial or who do not have a representative to confirm their participation * Hypersensitivity to any of the active ingredients of any of the branches of treatment, or to any of the excipients of its pharmaceutical form * Patients in whom increased blood pressure or blood pressure intracranial fluid poses a serious risk