Michael Breus is a clinical psychologist who branded himself The Sleep Doctor. He has been on every morning show that will have a sleep guy. The idea he owns in public is chronotype: lion, bear, wolf, dolphin. A quiz, a label, a permission slip to stop forcing a 5 a.m. club if you are a wolf. For a lot of patients, that permission is the whole intervention.
The clinical core underneath the animals is real. Circadian preference is partly genetic. Night owls forced onto a lion schedule carry a health cost. Light, caffeine, alcohol, and a regular wake time still do more than a stuffed-animal taxonomy. Take the quiz as a conversation starter. Then do Walker’s boring work: dark room, same wake time, no nightcap as a sleep strategy.
Breus is closer to a communicator-clinician than to a Berkeley sleep lab. That is fine for sleep hygiene. It is thinner when the chronotype chart starts sounding like destiny. You can shift a clock somewhat with light. You cannot litigate your genes on Instagram.

