I don't think it's ever a binary question of can versus can't. I think that the disease manifests as a source of internal distractions that are hard to ignore.

I don't think it's ever a binary question of can versus can't. I think that the disease manifests as a source of internal distractions that are hard to ignore. Think of pain. Imagine trying​ to take a test while someone was jamming a knife into your foot. I'm conjecturing that other distractions work in a similar way to pain. It has been noted that amphetamines are capable of relieving pain. That makes sense if you conceive of pain as a distraction that forces you to pay attention to it. Amphetamines allow you to concentrate harder on something else. There are most likely different forms of ADD or "ADD," and perhaps there is a form of ADD that acts directly on the brain's attention mechanism. We don't know anything about how the brain's attention mechanism works, so the idea that it can be​ broken is pure speculation.