- U.S., Earth
The 2015 report by the US Institute of Medicine/National Academy of Sciences, which looked at 9,000 publications on ME/CFS in coming to its conclusions, did not at all list "emotional lability" as a symptom of this disease. They were very clear in explaining that this is a complex, multi-organ system disease, and not a psychological problem.
Psychological symptoms can be caused by biochemical imbalances of various types, including under or overmethylation, zinc and copper imbalances, food allergies, amino acid deficiencies, microbiome imbalances, and a number of other issues.
Everything you say is 100% accurate. In recent years, the symptom of "emotional lability" has been left out of diagnostic criteria, precisely because it could be misinterpreted as suggesting a psychiatric cause for ME.
But if you read the original 1959 papers, all the authors made it quite clear that the "emotional lability" occurred in people with no prior history of "emotional lability", and that "emotional lability" is clearly a symptom, not a cause of ME.
So yes, mood swings and irritability can be symptoms of ME, even if we don't like to always acknowledge them. And they may well indeed respond to correcting biochemical imbalances, as I have experienced myself.