The Norwegian philosopher Peter Zapffe is little-known to most Anglophone readers. “The Last Messiah” is a 1933 essay that stands out as an important work in the sphere of philosophical pessimism. The views expressed are a kind of evolutionary existentialism. For Zapffe, angst, despair, and depression are due to our overly evolved intellect: we have an overabundance of consciousness. We think too much for our own good.
The Romanian philosopher Emil Cioran long struggled with insomnia, although he did not exclusively view it as a curse. He actually found insomnia to be an insightful condition, casting it as something distinctly human, as well as a state that could be highly productive for the philosopher.