The Speculator responded to the letter with a blend of commiseration and alarm: "this young gentleman's situation is truly pitiable. The cacoethes scribendi is certainly one of the most troublesome diseases of the mind; and when it thus totally possesses a man, I scarce know any madness equal to it" (51:20). The cacoethes scribendi, which as An Impartial and Candid Disquisition into the Case of Sporus, by A Lover of Truth and Impartiality (1755) explained, "is a hard Word for a Disease called in plain English, the Itch of Writing," was a staple of literary satire (24).
Source: wiktionary