:::The psych stigma argument is a cop out. Even the "king" of the cognitive behavioural approach apparently now interprets accusations of mental illness towards his patients as insulting. I agree with what was said above by anonymous about why "people with CFS are keen on fringe theories". Gaslighting is a rather strong term as it implies malicious abuse, but it does seem like some CFS patients are being tricked into accepting they have "false illness beliefs" and major psychological issues even when they don't. As for B12 treatment being "implausible", according to PMID 9310111, a small study (n=12) on women fulfilling both criteria for CFS and FM: "The most obvious finding was that, in all the patients, the homocysteine (HCY) levels were increased in the cerebrospinal fluid (CSF). [...] The most obvious finding was that, in all the patients, the homocysteine (HCY) levels were increased in the cerebrospinal fluid (CSF). There was a significant positive correlation between CSF-HCY levels and fatiguability, and the levels of CSF-B12 correlated significantly with the item of fatiguability and with CPRS-15. The correlations between vitamin B12 and clinical variables of the CPRS-scale in this study indicate that low CSF-B12 values are of clinical importance. Vitamin B12 deficiency causes a deficient remethylation of HCY and is therefore probably contributing to the increased homocysteine levels found in our patient group." -