As a confirmed melancholic, I can testify that the best and maybe only antidote for melancholia is action. However, like most melancholics, I suffer also from sloth.
Edward Abbey (1927-1989) American anarchist, writer, environmentalist
A Voice Crying in the Wilderness, ch. 4, “Life and Death and All That” (1989)
(Source)
Google book search shows that this comes from Abbey’s book “A Voice Crying in the Wilderness : Notes from a Secret Journal” page 43 (see this link)
Google Book Search absolutely rocks for this kind of research.
Thanks for the attribution.