Why Is Anxiety Worse at Night?

Lily Brown hears the same thing over and over again from her patients. They’ll say, “‘All day, I’m so busy. I’ve got deadline after deadline, responsibility after responsibility. And finally, I’m exhausted, I’m so excited to get to bed—and I lie down, and that’s when my brain turns on,’” says Brown, director of the University of Pennsylvania’s Center for the Treatment and Study of Anxiety. 

It’s all too common to spiral into worry and rumination once the sun goes down. Research has long suggested that...