No one here is suggesting that people are imagining their health condition, I'm certainly not, quite the opposite. We can criticise labels and hypotheses of causal mechanisms without suggesting that people aren't really ill.
There are legitimate problems with the MCAS label. It's not at all clear what it means. If someone thinks they know, please read our MCAS thread and then tell us on that thread. One issue with MCAS is that it provides a mechanism for the symptoms - in which case there needs to be evidence to support that mechanism. In contrast, ME/CFS is just a label for a recognisable pattern of symptoms. We aren't claiming to know the cause. When I looked into the MCAS literature, it didn't seem to hold together.
With POTS, my main questions are how relevant it is to ME/CFS and how reliable/repeatable the test results are. For sure, we have orthostatic intolerance. I think there is a pattern of increased heart rate, and possibly a pattern of the body trying to cope with an inadequate supply of blood to the heart and brain when upright, although fainting doesn't seem to be a typical part of ME/CFS. Repeated studies have not found anything like 70% of people with ME/CFS having POTS and we don't have good evidence that POTS treatments help us. There is confusion between POT and POTS, there is confusion about definitions. Things are not as clear as I once thought.
