Petrarch, Epistulae 13.7:
“My friend said, ‘Give me the keys to your cabinet.’ When I, wondering, had given them to him, he straightaway enclosed all of my books and all of my writing instruments, carefully locked it and left. He said, ‘I declare a ten-day holiday for you and therefore order you not to read or write anything during that time.’ I understood the game, and while I seemed to be at rest to him, I felt that I had been mangled. What do you expect? That day felt longer than a year, and was not without tedium. The next day, I had a had a headache from morning ‘til night. The third day arrived and I felt some little shakes from the fever. He returned when he learned of this, and gave me back the keys. So, I suddenly became better. Since he saw that I was afterward nourished by labor, he refrained from a similar attempt. What can I say? Is it true, as the satirist says, that the addiction to writing – as with all other things – is incurable? I would add – is it also contagious? How many do you think that I, who speak with you, have infected with the contagion of this disease? It used to be, within our lifetime, that almost no one wrote this stuff. Now, there is no one who doesn’t write.”
«Da» inquit, «michi claves armarii tui». Quas cum dedissem admirans, ibi protinus libros omnes meos atque omnia ad scribendum instrumenta conclusit obseravitque solicite atque abiit, et: «Decem» inquit, «tibi dierum ferias indico et ex facto iubeo nequid hoc tempore legas aut scribas».  Agnovi ludum: otiosus sibi, mancus michi remanere visus eram. Quid expectas? transiit dies ille anno longior non sine tedio; die altero dolorem capitis a mane ad vesperam passus sum; tertius dies illuxerat: quasdam febris motiunculas sentire ceperam. Rediit ille re cognita clavesque restituit; ita ego repente convalui et ipse postmodum me laboribus ali videns, ut dicebat, a simili se prece continuit.  Quid igitur dicam? ita ne verum est ut, sicut ceterarum rerum, sic scribendi “cacoethes insanabile”, quod ait Satyricus; quod ego addo, contagiosus etiam morbus sit? Quam multos enim putas me, qui tecum loquor, morbi huius contagiis infecisse? solebant in memoria nostra rari esse qui hoc scriberent.