Naturalistic Study of Ketamine in the Treatment of Depression

Inclusion criteria

Having a diagnosis according to DSM-5 for

* Major depressive episode as part of either Major depressive disorder, Bipolar I disorder, or Bipolar II disorder according to Fifth Edition of Diagnostic and Statistical Manual for Mental Disorders (DSM-5);
* 18 years old or older;
* Be able to provide written informed consent.episode;
* MADRS scale total score ≥ 12 and score in items 1 (apparent sadness) and 2 (expressed sadness) ≥ 2 during the screening period (baseline);
* YMRS scale total score ≤ 11 at baseline;
* Having current symptoms of suicidal ideation and/or behavior, according to the C-SSRS scores;
* Use of effective contraceptive methods in the case of heterosexual women of childbearing age;
* Indication/prescription of the attending physician for the use of ketamine, subcutaneous;
* For the patients with Bipolar I disorder: currently using lithium, valproic acid, or atypical antipsychotic at therapeutic doses for at least four weeks prior to initial evaluation.
* For patients with Bipolar II disorder: currently using lithium, valproic acid, lamotrigine, or atypical antipsychotic at therapeutic doses for at least four weeks prior to initial evaluation.

Exclusion Criteria

* Patients with an unstable, defined, or suspected systemic medical condition;
* Women who are pregnant, breastfeeding or planning to become pregnant within the next year;
* Patients who cannot tolerate the use of ketamine or who have previous adverse effects associated with ketamine;
* Inability to comply with informed consent or treatment protocol needs;
* Patients currently with psychotic symptoms (according to DSM-5 criteria);
* Patients with a current diagnosis of any active substance use disorder according to the MINI/DSM-5 criteria (with the exception of tobacco);
* Patients with autoimmune or inflammatory conditions, cancer or active infectious diseases.