Which medication is used for major depressive disorder in adults?

The correct medication for major depressive disorder in adults is Escitalopram. This medication is a selective serotonin reuptake inhibitor (SSRI), which is commonly prescribed to treat major depressive disorder as well as anxiety disorders. SSRIs like Escitalopram work by increasing serotonin levels in the brain, which can help improve mood and alleviate depressive symptoms.

Auvelity, while launched more recently as a combination of an NMDA receptor antagonist and a serotonin-norepinephrine reuptake inhibitor, is also used to treat major depressive disorder but in a different category than traditional SSRIs. It provides an alternative treatment option but does not represent the first line of treatment as Escitalopram does.

Gepirone, while investigated for the treatment of anxiety and depression, is not widely recognized as a standard treatment for major depressive disorder.

Lithium is mainly used as a mood stabilizer, particularly for bipolar disorder, and is not a primary treatment for major depressive disorder on its own.

In summary, Escitalopram is a well-established medication for treating major depressive disorder, making it the most appropriate choice among the options provided.