When was "rush" first used to describe a sudden intense feeling?
Solution 1:
It developed in the 18th and 19th centuries from a term meaning a rapidly growing emotion to something closer to the modern sense of a sudden, overpoweringly intense feeling.
The modern sense is what the OED gives as definition 2 b of "rush": "A rushing sensation in the body; a surge of euphoria, excitement, or energy, esp. one induced by drugs or some other stimulant."
The first reference cited is 1834. It refers to a rush of despair not euphoria, although the latter is the more common sense today: "He felt a rush as of a torrent to his temples;—his eyes grew dizzy—he was stunned by the greatness of his despair." (Edward Bulwer-Lytton)
From 1895: "This one felt a rush in his veins, a throb like the first which drove him on." (Deas Cromarty, pen name of Elizabeth Sophia Watson). There's another from James Joyce in 1922 which seems less clear out of context: "He couldn't get a connection. Only, you know, sensation. A dry rush." The sense specifically referring to drugs (which you don't seem to ask about) comes from the 1970s: the OED cites Frendz magazine in 1971.
This sense apparently derives from a weaker 18th century sense (2 a: "A surge of a particular emotion.") where it means an emotion coming over somebody, but probably less strongly and overpoweringly than the modern sense. For instance: " The sudden Rush of painful Ecstasie!" (1722) or "Heard you that rush of woe." (1770) Talk of "rush" in the sense of emotion moving fast is a natural development from the sense of sudden movement or flow, which dates to around 1500.
Source: "rush, n.2, adv., and adj." OED Online. Oxford University Press, March 2021. Web. 10 May 2021.