What does Elon Musk think of productivity drugs like Modafinil?

I've been reading some articles about Elon Musk.
In this one here at Huffington post : Smart Drugs: Secret of the World's Tech Billionaires? (http://www.huffingtonpost.com/jonha-revesencio/smart-drugs-secret-of-the_b_6614954.html) says that he never addresed this issue publically.
But there is another one that gave me the most of the impression I have about this man : 7 Quotes That Help Explain Why Elon Musk Is Such a Hot Shot (http://www.inc.com/cameron-albert-deitch/seven-elon-musk-quotes.html)
In particular one of the quotes in which he says : “Optimism, pessimism, f* that**--we're going to make it happen. As God is my bloody witness, I’m hell-bent on making it work.”
I think Elon Musk relies only in his strong will and in his intuition as an enterpreneur instead of nootropic drugs . This is my opinion.

This post comes from my original answer on Quora here
https://www.quora.com/What-does-Elon-Musk-think-of-productivity-drugs-like-Modafinil/answer/Alket-Cecaj?srid=n9bS