While the manic phase of depression and its attendant outpourings is obviously useful to the writer, surprisingly, so is the depressive phase, which Kay Redfield Jamison suggested served a “critical editorial role”. Depression forces one into introspection, and turns a into their own harshest critic. Susan Greenfield described the manic depressive’s world as “the product of a brain with an exaggerated mind, an over-extensive buzzing of neuronal networks... whereas in childhood or under drug influence, such associations would be sparse and superficial, in depression they would be the opposite: overdeveloped and overused.... Just as strong emotions characterize a mind where brain connectivity was under-working, so the depressive trapped in his or her own mind feels the opposite—no emotions, a numbness.”
Greenfield went on to describe the root cause of manic depression as “an unusual instability in the factors that control the formation of working neuron networks... there is a stage when the assemblies formed are too small (mania), and then some compensation intervenes such that they rebound to become too large (depression), and so on.” While researching or planning, a writer forms vast webs of information, collecting a range of disparate facts and organizing them into a whole. The information is processed into words and released from the brain: then the cycle begins again, with the writer assimilating more information and tying it together in more new and strange ways. So the rhythms of manic depression match the rhythms of writing: periods of prolific writing (where the neural networks are reduced and limited, resulting in mania) alternate with periods of intense planning or revising (where large networks of connections are formed, similar to depression). Not surprising, then, that a tendency towards writing and manic depression coexists.