Anhedonia and It — "Hal isn’t old enough yet to…"
Hal isn’t old enough yet to know that this is because numb emptiness isn’t the worst kind of depression. That dead-eyed anhedonia is but a remora on the ventral flank of the true predator, the Great White Shark of pain. Authorities term this condition clinical depression or involutional depression or unipolar dysphoria. Instead of just an incapacity for feeling, a deadening of soul, the predator-grade depression Kate Gompert always feels as she Withdraws from secret marijuana is itself a feeling. It goes by many names—anguish, despair, torment, or q.v. Burton’s melancholia or Yevtuschenko’s more authoritative psychotic depression—but Kate Gompert, down in the trenches with the thing itself, knows it simply as It.
Context
The taxonomy's hinge: anhedonia demoted to remora, the Great White Shark of pain introduced, and the capital-I It named — the word Kate has used since her ward interview. (Carlisle sets this It beside Tolstoy's capital-I It in The Death of Ivan Ilych — his best source-catch of the pass. "Yevtuschenko" spelled thus.)