So I think what you're saying is that patients were expected to stick to an exercise program of increasing intensity? Was this ignorance of PEM or more likely that most people didn't believe it was real? (I guess it could be both but if anyone has first hand experience please share)
Yes, traditionally the goal was to increase activity, without allowing any respite in reaction to symptoms. The advocates of GET and activity-oriented CBT knew that patients had more symptoms after exertion, so they were not ignorant of it.
Most of the research articles I've seen mentions UK. Was this a larger issue there or have patients in US and Canada and other places having the same issue.
It has primarily been an issue in the UK. A group of like-minded researchers emerged there, and generally fed off of each others' theories and work. The Netherlands has seen a similar problem, but it started more recently and there's much less public interest in it. This is probably largely due to the UK group being heavily oriented at spreading their message and very specifically targeting those in power. Wessely especially has been a charismatic force in the UK - he says a lot of godawful things, but he sounds quite charming while doing it.
Doctors or researchers really thought this exercise was going to cure patients?
Perhaps initially, but I think the researchers and self-proclaimed specialists promoting GET had to know better at some point. They would have been seeing massive rates of complete failure, even when using a diagnostic criteria only requiring fatigue. But other doctors and researchers who merely read their papers or abstracts, would likely take those claims at face value.
So the hypothesis behind GET is that patients thought they were sick, were falsely convinced that exercise/work/activity was making it worse and "good medicine" was to show patients they could return to normal and eventually no longer need to claim sickness?
Sort of. But that's not how GET came about. The Wessely school started with a basic premise about 20-25 years ago: illness-denial CBT is the cure. They worked backwards from there to try to explain how it worked, even when it wasn't actually working. Initially GET was incorporated into CBT with the explicit caveat that it worked because it was overcoming beliefs, not because it was resulting in any increased activity. In fact, the researchers said the amounts of exertion used were incapable of having any physiological impact.
But then that model was contradicted by physiological abnormalities found in ME/CFS patients, most specifically Orthostatic Intolerance. Plummeting blood pressure when standing up is obviously not the result of simply believing we are ill. Instead of scrapping the entire psychosomatic theory, they still maintained that CBT was ultimately the cure. But they refined their theory to state that our erroneous beliefs resulted in us becoming less active and deconditioned, thereby resulting in our more objective signs of illness. So GET became an even more important part of CBT, but now with the presumption that it was curing us by getting us to work our way out of our supposed deconditioning.
In the past 5-10 years, actometer data has proven that ME/CFS patients treated with CBT and/or GET do not become more active, even if they report significant improvement on questionnaires. So the new conclusion is that subjective reports of fatigue are the most important factor in determining illness and recovery. This ignores the objective disability experienced by patients, so they simply don't talk about that anymore. The image they try to create is that there is no substantial disability, and that our belief that we have symptoms is caused solely by our fear of activity. Of course, under this model CBT is still touted as the cure, with GET used to supposedly teach us that our presumed phobia is misplaced.
And in the past several years, at least three groups have produced studies showing that we have an objective reaction to exertion which is not present in sedentary/deconditioned controls. Deconditioned people might show mildly reduced capacity on a single Cardio-Pulmonary Exercise Test (CPET), but even moderate ME patients have a large reduction in their VO2max. Basically that means that they hit their physical limits much sooner than healthy or deconditioned controls. More interesting is that when even mild ME patients take a second CPET 24 hours after the first one, they have a dramatic decline in function. Healthy and deconditioned controls do about the same on both days, or slightly better on day 2. This objectively confirms the existence of PEM, and demonstrates that it is a biological reaction, not the result of maladaptive thoughts or behaviors.
Again, the psychosomatic proponents remain completely silent regarding the CPET. I have never seen one attempt to explain away the results seen in ME. It might even be a major factor behind some classic CFS psychobabblers jumping ship and abandoning CFS research, including Simon Wessely. Instead they ignore the CPET and the other growing sources of biological evidence, and focus on championing CBT and accusing patients of being biased against psychiatric illnesses if we dare object on any grounds.
Another possible shift, which they've shown tentative signs of in the past is claiming that even if a disease is proven biological, there is still a psychosomatic component. Basically they suggest that some symptoms are real, and others are imagined. To reach this conclusion, they use certain depression and anxiety questionnaires where physical disability and symptoms are presumed to indicate psychological dysfunction. They likely find this approach very appealing because it can be applied to any chronic illnesses, especially ones with the involvement of multiple biological systems and many diverse symptoms. And of course (say it with me): "CBT is the cure."
The one consistency in their forced evolution of their hypothesis is that CBT (with or without GET) is always the cure. From there they will work backward to try to prove how it is done, while employing various methods to dodge around the incontrovertible evidence of biological involvement. I think they're running out of ideas for how this can be plausibly explained, and many are running for the hills, leaving the much stupider ones behind to say increasingly absurd things about the disease which are easily disproven.