I’m enjoying Catherine M. Andronik’s book for teens, Wildly Romantic: The English Romantic Poets (The Mad, the Bad, and the Dangerous).
She writes: "Like so many of his fellow poets, the key event in the early life of John Keats was the death of a parent — his father Thomas Keats [when John was nine]."
I theorize that the death of a parent when a kid is young tends to stunt his emotional and social development, thus leading him to write as a way of expressing his frustration.
By age eight, I had retreated into a fantasy world. I’ve only intermittently left it since. I experience my strongest emotions after the triggering event, when I feel safe (and usually alone).