Evaluation of the Efficacy and Safety of Subcutaneous Ketamine in the Treatment of Depressive Episode With Suicidal Ideation and/or Behavior in Adolescents

Inclusion Criteria: * Age between 12 and 19 years. * Diagnosis of Major Depressive Episode, unipolar, made through the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS-PL) administered by experienced evaluators, using DSM-5 criteria. * Under usual treatment for Major Depressive Episode, including clinically indicated psychopharmacological treatment and/or psychosocial treatment at one of the two collaborating clinics (DICA and Conversas de Vida / Unifesp). * Score ≥ 25 on the MADRS (Montgomery-Åsberg Depression Rating Scale). * Score ≥ 28 on the CDRS (Children Depression Rating Scale). * Score ≥ 2 on the Columbia Suicide Severity Rating Scale (C-SSRS). * History of suicide attempt or significant suicidal ideation or planning with a plan or intention requiring emergency evaluation in the last 30 days. Exclusion Criteria: * Presence of the following psychiatric comorbidities: Autism Spectrum Disorder, Bipolar Disorder, Schizophrenia, Schizoaffective Disorder, or psychiatric disorder secondary to physical illness, and history of ketamine or other substance abuse or dependence in the last 6 months. * Presence of Intellectual Disability (assessed by IQ testing). * Presence of the following clinical comorbidities: history of myocardial infarction, congenital heart disease, decompensated cardiac arrhythmia, decompensated hypertension, porphyria, stroke, brain trauma with loss of consciousness, intracranial hypertension, hydrocephalus, central ner…