But, I also found this interesting link on the Lancet webpage itself.
Doubts over the validity of the PACE hypothesis
Here is the final paragraph:
The PACE trial is to our knowledge the largest investigation of CBT and GET for chronic fatigue syndrome to date. The deconditioning hypothesis was not supported, and the fear-avoidance hypothesis was not supported by the trial's objective outcomes. These factors, along with the disappointing self-report clinical response rates for CBT and GET in an open-label trial, cast substantial doubt over the validity of the fear-avoidance and deconditioning hypothesis for chronic fatigue syndrome.