How can I convince someone who has ADD (attention-deficit disorder) to get help?

The person I'm speaking of shows symptoms of the disorder, but whenever I suggest consulting a psychiatrist to confirm, he insists that he is "not crazy". I've tried to explain him that it is as natural as being diabetic (tried to make the insulin-dopamine connection) but the fact that he won't listen makes it a little harder to do so. I normally do not exactly approve of medication for mild mental conditions, but I believe he will be much more productive in his daily life if he at least consults an expert. Any ideas?