[kawa]

Whats a "disease" and whats not is not easy to define. If we could look at the living brain at a microscopic level, comparing individual dopamine receptors and the connectome of individual brains, it would be quite easy to give objective evidence for most mental diseases. But we can't. But we can see viruses and tumors and that leads to your idea that those are more "real" because it's more easy to see them. But is "visibility" really a valid criteria here?

For example look at a disease like fibromyalgia: For a very long time there was no objective evidence that this disease really existed, so people suffering from it where often seen as hypochondriacs. Today we know it's really a disease because modern medicine found ways to make it "visible" so it's accepted as a real disease now. But with your way of thinking you would've denied those people analgesics because a few years ago there was no objective way to tell if they really suffered the pain they reported.

OTOH depression is still an "invisible" disease: You can only look at the symptoms to diagnose it, there is no "objective" evidence for it. But still there are lots of people suffering and dying from it. And we know from lots of studies that it's possible to cure or at least manage this disease for a certain percentage of sufferers. So I would consider it unethical to let people suffer or even kill them self only because we can't see objective biological evidence that they have depression.

Now with ADHD it's not as clear as with depression because the symptoms aren't that severe. So you argue that it's just the society which wants "conforming" individuals and declares non-conforming ones as "ill". But if people are really disabled by something which prevents them doing certain things they want to do which the majority (> 90%) of people can do, while medication exists which let them do it, is it really ethical to not give them the medication? Those people are objectively suffering and there exists lots of evidence that their suffering can be reduced be giving them a certain medication. So it's unethically to let them suffer even if there exits a way to stop their suffering.

And yes, if there would be a medication which could lift the IQ of person with low IQ into the average range, I would also consider it unethically to not give this medication to people with low IQ. But such a medication don't exists today.