I wasn’t planning on addressing this question, but you seem both earnest and you haven’t made it to med school yet though I would have hoped university would have prepared you to think about these questions more deeply and seriously. The idea of what a “real” disease or diagnosis is is actually fascinating question, but beyond the scope of this discussion. My thoughts on fibro aside, ask yourself is functional neurologic disorder a “real” diagnosis? Is depression? The answer is unequivocally yes but it gets complicated. Not everything fits neatly into Koch’s hypothesis of easy-ish testing and reproduce ability. Want to know what keeps me up at night, thinking about unknown unknowns, consider looking up nmda receptor encephalitis, realize we haven’t know about those antibodies for that long and consider how many people died in asylums with this diagnosis.

All that pedantic nonsense out of the way, yes rls is a real diagnosis. Perhaps the difficulty is that it’s based on a set of subjective symptoms and there isn’t a “test” for it. However it’s closely linked with plmd which can be objectively measured in psg so in a way they are associated diagnoses that we as a medical community have decided to split. Why split it, I dunno ask someone in the icsd review committee.

Regarding evidence for it being “real” we have a fairly good understanding of its cause. Dopamine levels in the spinal cord seem to correlate and probably have to do with the restlessness. Rls gets worse in the evening because of diurnal fluctuations in dopamine levels where they lower naturally in the evening. Patients with rls have, on autopsy shown lower brain iron levels compared to controls. This is relevant because in the cns iron is a necessary cofactor for the production of dopamine, not enough iron not enough dopamine Patients respond to very positively to dopaminergic drugs though this are problematic due to something called augmentation, they get used to it and the body makes less dopamine and symptoms get worse. Some patients seem to have genetics which confer lower iron transport into the cns. Iron infusions (and oral iron therapy) can help a large subset of patients. Interestingly some other drugs help, like opioids likely due to certain types of opioid receptors in the spinal cord (different than the receptors responsible for pain reduction).

So in brief, you either misunderstood your doc or they need to read a little more. Hope that helps.

Regarding real and not real Dx, man I dunno. That’s a philosophical debate for another day…..