We know that depression affects people from all walks of life. Rich. Poor. Celebs. Ordinary Joes. Young. Old. But, somehow after the death of Robin Williams, there's a renewed focus on depression, and my mind turned immediately to a lecture we featured on the site way back in 2009. The lecture is by Robert Sapolsky, a Stanford biologist, who has a talent for making scientific subjects publicly accessible. A recipient of the MacArthur genius grant, Sapolsky notes that depression --- currently the 4th greatest cause of disability worldwide, and soon the 2nd -- is deeply biological. Depression is rooted in biology, much as is, say, diabetes. As the lecture unfolds, you will see how depression changes the body. When depressed, our brains function differently while sleeping, our stress response goes way up 24/7, our biochemistry levels change, etc. You will see that biology is at work.

Sapolsky is one compelling teacher. So you might not want to miss his Stanford course, Introduction to Human Biology. It's equally worth your time. You can always find it housed in our collection 1,500 Free Online Courses from Top Universities.

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