Nature vs. Nurture, Part Infinity.

The Times has a (very) belated obituary of Sylvia Plath this morning, the poet and author of The Bell Jar, who committed suicide at age 30.

What caught my eye in particular was this sentence:

Biographers have linked Plath’s bouts of depression to the childhood trauma of losing her father, as well as to her own perfectionism and her mother’s smothering nature.

Really? Maybe she was just plain born with depression. (Aren't biographers presumptuous? I mean, really, how the hell do they know why Plath suffered from depression?)

In the previous paragraph it says:

Worse was when Plath’s son, Nicholas, a fisheries biologist in Alaska, hanged himself in 2009, at 47.

Hmm. What was the cause of his depression? Could it be . . . hereditary?