Why does the placebo effect appear to be getting stronger?

Science!

* 'Runner's high' confirmed by brain scan.

* Seven to thirteen minutes. That's all it takes. I'm a little tempted to throw up the "Business Time" video again, but I'll restrain myself for now.

* A classic study from 196 shows the placebo effect working even when the patient knows it's a placebo. Another study from 2002 shows the efficacy of placebo anti-depressants increasing over time (!), presumably as the idea of an anti-depressant gained more cultural capital. And a study released this week shows that more expensive placebos are more effective than cheap or free placebos.