"Nepenthe" is a name from ancient Greek, meaning "no sorrow."  It referred to a legendary drink to dispel grief.  (So the ancient Greeks had the concept of "antidepressant", even if they did not necessarily have the pharmaceutical technology.)  "Nepenthe" is sometimes (depending on the author) conflated with the River Lethe, one of the rivers of the underworld, whose waters the spirits of the dead drink to forget their mortal lives.

From the classical Greek, the name Nepenthe, for a cure for troubles, has passed into other literature.  Two famous examples:

Edmund Spenser, 1596

Faerie Queene

Book 4, Canto iii

Nepenthe is a drink of sovereign grace,

Devised by the Gods, for to assuage

Heart's grief,

                      and bitter gall away to chase,

Which stirs up anguish and contentious rage.

Instead thereof sweet peace and quietage

It doth establish in the troubled mind.

 

Few men, but such as sober are and sage,

Are by the Gods to drink thereof assigned.

But such as drink, eternal happiness do find.

Nathaniel Hawthorne

The Scarlet Letter

Chapter 4

The physician ... next bestowed his attention on the mother {Hester}. With calm and intent scrutiny, he felt her pulse, looked into her eyes ... and, finally, satisfied with his investigation, proceeded to mingle another draught.

 

"I know not Lethe nor Nepenthe," remarked he; "but I have learned many new secrets in the wilderness, and here is one of them.... Drink it! It may be less soothing than a sinless conscience. That I cannot give thee. But it will calm the swell and heaving of thy passion, like oil thrown on the waves of a tempestuous sea."