How does light therapy help treat seasonal depression?

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Kelly Rohan |

TED-Ed

• December 2025

As winter approaches, shorter days spark a cascade of changes within the brains of animals. As a result, groundhogs retreat to their burrows for hibernation, weasels’ coats turn from brown to white, and birds cease their singing. And scientists are finding that seasonal behavioral changes similarly happen for some humans. Kelly Rohan digs into what we know about seasonal affective disorder. [Directed by Avi Ofer, narrated by Bethany Cutmore-Scott, music by Cem Misirlioglu].