Most of us have heard about the winter blues, but do you know where the saying comes from? Every year, millions of Americans suffer from mild to severe cases of the winter blues, a condition known as seasonal affective disorder, or what’s commonly referred to as SAD. On this week's Fordham Conversations, WFUV's Katie Fisher is joined by Fordham University Professor of Chemistry Joan Roberts who's an expert on SAD. Dr. Robert's talks about the cause of seasonal depression and the powerful impact light has on health.