My New Stream of Consciousness.

n. the unsettling realization that each random passerby is living a life as vivid and complex as your own—populated with their own ambitions, friends, routines, worries and inherited craziness—an epic story that continues invisibly around you like an anthill sprawling deep underground, with…

Excerpt:

A remarkable and novel theory for depression emerges from these studies. Perhaps some forms of depression occur when a stimulus — genetics, environment or stress — causes the death of nerve cells in the hippocampus. In the nondepressed brain, circuits of nerve cells in the hippocampus may send signals to the subcallosal cingulate to regulate mood. The cingulate then integrates these signals and relays them to the more conscious parts of the brain, thereby allowing us to register our own moods or act on them. In the depressed brain, nerve death in the hippocampus disrupts these signals — with some turned off and others turned on — and they are ultimately registered consciously as grief and anxiety. “Depression is emotional pain without context,” Mayberg said. In a nondepressed brain, she said, “you need the hippocampus to help put a situation with an emotional component into context” — to tell our conscious brain, for instance, that the loss of love should be experienced as sorrow or the loss of a job as anxiety. But when the hippocampus malfunctions, perhaps emotional pain can be generated and amplified out of context — like Wurtzel’s computer program of negativity that keeps running without provocation. The “flaw in love” then becomes autonomous and self-fulfilling.

We “grow sorrowful,” but we rarely describe ourselves as “growing joyful.” Imprinted in our language is an instinct that suggests that happiness is a state, while grief is a process. In a scientific sense too, the chemical hypothesis of depression has moved from static to dynamic — from “state” to “process.” An antidepressant like Paxil or Prozac, these new studies suggest, is most likely not acting as a passive signal-strengthener. It does not, as previously suspected, simply increase serotonin or send more current down a brain’s mood-maintaining wire. Rather, it appears to change the wiring itself. Neurochemicals like serotonin still remain central to this new theory of depression, but they function differently: as dynamic factors that make nerves grow, perhaps forming new circuits. The painter Cézanne, confronting one of Monet’s landscapes, supposedly exclaimed: “Monet is just an eye, but, God, what an eye.” The brain, by the same logic, is still a chemical soup — but, God, what a soup.