JUDY WOODRUFF:

Now: why some psychiatrists and researchers are giving psychedelic drugs a second look as a possible way of treating depression and some mental illnesses.

The idea had been shunned for years, but now some say a time for larger trials with the drugs is due.

Miles O'Brien has the story for our weekly segment on the Leading Edge of science.

SGT. C.J. HARDIN (RET.), U.S. Army Veteran: I was diagnosed with post-traumatic stress disorder in Fort Campbell.