The anesthetic ketamine can relieve depression in hours and keep it at bay for a week or more.

Now scientists have found hints about how ketamine works in the brain.

In mice, the drug appears to quickly improve the functioning of certain brain circuits involved in mood, an international team reported Thursday in the journal Science. Then, hours later, it begins to restore faulty connections between cells in these circuits.

As far back as he can remember, George McCann lived in fear. When he was asleep he would have horrific nightmares filled with violent images. When he was awake, he often felt threatened by people, including members of his own family. And when he felt threatened, he would become aggressive, even violent.

George spent his childhood certain that something very bad was going to happen. And when he was 12, it did. His unrelenting fears led to a violent outburst at school. And George landed in a psychiatric hospital.