There are studies that show an objective, substantive and lasting effect for patients from CBT/GET. They are as subset of the studies showing no benefit or a worsening ... so the effect, if any, is to get worse. The other studies use potentially highly biased subjective measures. The six minute walk test shows a tiny effect that is entirely expected, and leaves patients in the highly disabled spectrum which is reclassified to normal in some cases. Some studies show temporary gain which is not sustained. In other areas of medicine this is often found to be due to bias. Not so here. Bias? No way!