“The Seducer’s Diary” by Søren Kierkegaard: In the Foreword, Novelist John Updike cites a psychological cause for Kierkegaard’s Multiple Personality (Dissociative Identity), as an asset for “indirect communication”

Wikipedia (1) lists Kierkegaard’s alternate identities with minds of their own, but he had not been diagnosed with multiple personality, because of no obvious history of a psychological cause (i.e. childhood trauma, etc).

“This work (The Seducers Diary), a chapter from Kierkegaard’s first major volume, Either/Or, springs from his relationship with his fiancé, Regine Olsen…but then he broke off their engagement…Olsen became a muse for him. His attempt to set right what he felt was a mistake taught him the secret of “indirect communication” (2, back cover).

Comment: I had been puzzled as to why a person with such well-known alternate, writer personalities had never been diagnosed. His dissociative identity, like that of most novelists, was mostly an asset (what I call “Multiple Personality Trait,” not Disorder).

1.Wikipedia. “Søren Kierkegaard.”

https://en.wikipedia.org/wiki/S%C3%B8ren_Kierkegaard

2. Søren Kierkegaard. The Seducer’s Diary with foreword by John Updike. Princeton University Press, 1997.