Andrew Huberman· PhD
And a classic example of that is what we call 'early morning awakening'. And this is something that can happen very early as people start to slide into depression. They start to wake up earlier and earlier, just inexplicably, they're awake at- - This is like 2:00 AM, 3:00 AM awakening? - It could start... Yeah, it could start at 5:00 AM, could go to four, and three- - And are unable to fall back asleep? - Unable to fall back asleep. Exactly.