i had early-onset. two of my (best) psychiatrists said that understands early onset bipolar to likely cause rapid cycling bipolar, aka many people diagnosed young actually are rapid cycling. i had 6 hospitalizations before 20, and 2 of those were for severe mixed episodes, hence the BP diagnosis @ 16...though medically speaking, i was not old enough to be "diagnosed". regardless, i've been treated for BP1 rapid cycling since then. i feel as though i lost much of my adolescence to this illness, but i suppose that was simply its course at the time.