Which antidepressant is known for its effects on both the serotonin system and receptor antagonism?

The correct choice highlights Mirtazapine's unique pharmacological profile in the treatment of depression. Mirtazapine functions primarily as a noradrenergic and specific serotonergic antidepressant (NaSSA). It enhances neurotransmission by blocking certain serotonin receptors, specifically the 5-HT2 and 5-HT3 receptors, which can lead to decreased anxiety and improved mood. This action complements its effect on norepinephrine release, providing a dual mechanism that can be beneficial for patients who do not respond adequately to standard selective serotonin reuptake inhibitors (SSRIs).

In contrast, the other options primarily target serotonin reuptake without receptor antagonism. For instance, Venlafaxine and Duloxetine are serotonin-norepinephrine reuptake inhibitors (SNRIs) that inhibit the reuptake of serotonin and norepinephrine but do not act as receptor antagonists. Fluoxetine, on the other hand, is a selective serotonin reuptake inhibitor (SSRI) and is solely focused on enhancing serotonin levels without receptor blocking effects. Mirtazapine's multifaceted approach offers an alternative treatment pathway, making it a suitable choice for certain patient populations, especially those with comorbid anxiety or who experience side effects from