There is no Hope without Fear, and no Fear without Hope.
Today's Times, drawing on now famous research by Jerome Kagan, features a long review article on anxiety and it's relation to temperament. This is a great example of science confirming ancient intuition, in this case the fact that persons really are wired differently from conception. As the article states, any emotion has three components: physiology, subjectivity, and behavior--the question for life is how far the latter two can be unyoked from the first.
I don't have a great deal to say about anxiety except that as compared to the other major mental disorders--mood, psychosis, and substance abuse--it may be the one most likely to hide in plain sight. Anxiety can generate profound misery and grave impairment but does not, in itself, advertise by means of catatonia, craziness, or intoxication. And while all psychological symptoms exist on gray continua, the point at which anxiety becomes pathological may be the hardest of all to pinpoint. Anxiety, after all, is adaptive.
Anxiety and depression often travel together, but arguably they present differing core experiences. If the sine qua non of depression is loss (of a good, of an attachment), that of anxiety is dissatisfaction, the feeling that something is wrong that cannot be set right. In obsessive-compulsive disorder it is the immediate environment that is defective, while post-traumatic stress disorder entails a deep flaw in (social) reality itself--the world itself becomes antagonistic. For the socially anxious, it is the self that is unacceptable. And perhaps generalized and panic anxiety are the most closely aligned to fear, such that the future itself cannot be trusted.
If psychosis is metaphysical, and if the phenomenology of depression is somehow religious--the suspicion that there is not, in the end, enough good in the universe to make up for the bad--then the experience of anxiety is fundamentally moral and/or aesthetic--it is desperately important that something be made right. The other day D. G. Myers at A Commonplace Blog proposed a list of the "most depressing novels of all time" (I agreed with the choices with the notable exception of Miss Lonelyhearts, which is darkly hilarious, and not at all depressing). What are some of the most anxiogenic writings of all time? Hamlet, surely, inasuch as his uncle's perfidy and his mother's frailty constitute the rotten taint at the root of the prince's world. "Notes from the Underground." "The Waste Land." The Trial. Others?