Fowles' narrator, a man of his (Fowles') time, has considerable respect for Freud and attributes hysteria to sexual repression in Chapter 28, a report of the La Ronciere case of 1835.
Another generation advised that masturbation causes warts, impotence, sterility, homosexuality, and even insanity.
Much as poverty causes crime, war, and even Jihad.
Reading The French Lieutenant's Woman.
Our author quotes Hardy and Clough, Marx and Freud.
And Tennyson more than anyone.
But never once, so far, Nietzsche, Leopardi, or Schopenhauer.