"She can perceive a hallucination or fantasy as utterly real to her but also not real to the rest of the world, and thus not something that she should really act upon."

THE TOUCH OF MADNESS

Culture profoundly shapes our ideas about mental illness, which is something psychologist Nev Jones knows all too well.

"Jones knew she was acting odd. She worried first that her classmates could tell something was off, and then, as her self-consciousness slid into paranoia, that they could read her thoughts. She began to have vague and then troublingly specific visions of harming herself. Later she would recognize these, as well as other fantasies still to come, as examples of a psychotic phenomenon that Eugen Bleuler called "double registration" or "double bookkeeping." In double bookkeeping, the psychotic person keeps two ledgers. She can perceive a hallucination or fantasy as utterly real to her but also not real to the rest of the world, and thus not something that she should really act upon. Jones later explained this idea to me as we were walking across the Stanford campus. She might well see a red rabbit grazing on the lawn before us, she said, and that rabbit might seem as thoroughly real as my presence next to her. But she would also recognize that the rabbit was not real to the rest of us, and that I was, and that she should not expect me or anyone else to perceive it. Likewise with the stone walls whose double nature Jones had so vividly perceived, stiff enough to break her toe but vaporous enough to blow into particles with her breath. In this double-bookkeeping version of reality, you could indulge the reality shown on the private ledger even as you lived according by the ledger that everyone else read from. It was usually fantasy, not intention. So it is with even many of the violent fantasies that some psychotic people have. While such fantasies are not uncommon (in non-psychotic people too), psychosis raises the likelihood of violent behavior only modestly, to roughly that of people who struggle with substance abuse."