As a professional doctor science man, this is indeed un-advisable and would lead to so many bad habits and mental issues later. Not to mention that, while this might by chance get you into grad school, it is less likely to grant you a title or a livable job anywhere. I've met a couple of cases, we would advice them that they should get diagnosed and medicated. One such case was a study mate for 5 years, he already had been 5 years there before I met him. It was public uni so he was free to try as much as he wanted for a title as long as he was above a certain minimum performance. He consistently wasn't good enough to graduate but also wasn't bad enough to get kicked out. Another one did get diagnosed and medicated and immediately realized he hated university and was only doing it for their parents who weren't supportive at all. Dropped out, got into music and now is happy as can be playing bars in Europe.