Articles

Major depressive disorder (MDD) is a significant psychiatric condition, with many affected individuals not gaining remission from conventional treatments, leading to classification as treatment-resistant depression (TRD). This study aimed to investigate the potential of intravenous (IV) ketamine, particularly the S-enantiomer esketamine in nasal spray form, for treating patients with TRD and associated comorbidities. We report three cases of patients with diverse psychiatric and medical backgrounds whom all reported significant symptomatic relief from depressive episodes and suicidal ideation (SI) following esketamine administration. Additionally, esketamine seemed to proffer benefits beyond the primary depressive symptoms, positively impacting other comorbid conditions, such as agitation, self-injurious behavior (SIB), and chronic pain. The goal of this paper is to highlight that while esketamine's primary utility is in addressing TRD, its therapeutic potential may extend to a variety of associated conditions. However, it is crucial to underscore the heterogeneity of MDD, emphasizing the necessity for individualized therapeutic approaches and further research into esketamine's broader applications.

Major depressive disorder is characterized, among other symptoms, by depressed mood and anhedonia associated with a high rate of suicidal ideation. In recent years, research has shown reduced expression of the brain-derived neurotrophic factor (BDNF) in limbic areas of individuals with depression. This reduction of BDNF is reversed by antidepressants in animal models of stress. Stress is one of the main triggers of mood disorders such as depression. Also, administration of BDNF increases the number of serotonergic fibers and serotonergic innervation, indicating an increase of serotonin in the synaptic cleft by this neurotrophin. Thus, BDNF appears to be one of the targets of antidepressant drugs for the increase of monoamines and remission of symptoms of major depression. The purpose of this review was to show the evidence that indicates BDNF as a molecular substrate for vulnerability to depression and the response of this substrate to the antidepressants.