Scientists have come up with theories about the evolutionary purpose of depression, some suggesting it was useful as a means for some people to withdraw from society and ruminate on difficult problems. However, an article in the Psychiatric Times questions this theory.

Meanwhile, if you have a bit of time on your hands, check out an account in the New York Times about a life in psychotherapy and how useful or not it might have been.

And finally, news of a thought-controlled prosthetic limb set to be tested on humans.

(Photo: by travlinman43 on flickr)