In his usual Teflonic and ironic fashion, The Donald managed to skirt the issue of the long list of performance-and-other drugs given out like candy at his White House, and the persistent accusations that he's the one on drugs. That he offered to take such a test himself means nothing, considering that he has no compunction about cheating on elections, his wives, and almost everything else. The fact that his plan was backed by former White House doctor Ronny (as in Reagan) Jackson (whose name Trump got wrong while bragging about passing the cognitive tests he administered), makes me wonder if his dastardly plan was to have Dr. Johnson-Jackson administer the tests, duly bribed to provide a negative result for Trump.
Leading up to the debate, MSNBC's Rachel Maddow laughed heartily at Chis Hayes's pronouncement that, "If performance drugs make you a better debater and president, I'm all for them." My twitter feed ruminated a bit on that, pointing out that it's "too bad the performance enhancers Trump is on make him even more delusional, narcissistic and evil."
Then Jon Stewart, who appeared live post-debate, nailed the thought as only he can (because, Great Heads Think Alike):