by ooli

Each one-hour earlier sleep midpoint (halfway between bedtime and wake time) corresponded with a 23% lower risk of major depressive disorder.

This suggests that if someone who normally goes to bed at 1 a.m. goes to bed at midnight instead and sleeps the same duration, they could cut their risk by 23%; if they go to bed at 11 p.m., they could cut it by about 40%.

Someone didn't get the memo about correlation/Causation. People raising early are likely to be less depress, does not equate with "raise early and you cut the depression rate by 23%"

"We live in a society that is designed for morning people, and evening people often feel as if they are in a constant state of misalignment with that societal clock," said Daghlas.

This sound more as an explanation