Major depressive disorder (MDD) affects approximately 280 million people globally and is one of the leading causes of disability. One in every three people suffering from MDD also has to deal with treatment-resistant depression (TRD), a condition where patients do not respond to at least two antidepressant trials. Esketamine nasal spray, a rapid-acting anti-depressant, is known to be effective against TRD when administered alongside antidepressants like selective serotonin reuptake inhibitor (SSRI) or a serotonin-norepinephrine reuptake inhibitor (SNRI). A study retrospectively compared the effectiveness of both the combinations in treating TRD and found that esketamine plus SNRI showed significantly better overall...