As someone with ADHD who just (about 5 days ago) discovered how magical the right stimulant is for instantly vaporizing all disordered symptoms, I'm pretty sure giving patients the choice will always be better than treating or not treating them based on ethical implications.

Choosing not to treat someone because "they may contribute to society", even if they are suffering and wish not to suffer from their treatable disorder, is always unethical imho.

However, forcing treatment on someone who either doesn't want to pursue treatment, or has tried treatment and decided against it, would also be unethical.