Originally Posted by mmk
Well, as those who have kids with ADHD can attest, there are drugs which can make you more calm and focused, e.g., adderall. ADD/ADHD drugs aren't necessarily illegal, but they are controlled substances. I don't know what the ITF rules are on these drugs, but in other sports they are legal if there is a prescription. However, I doubt that Fed is taking any such drug.
Over time dependency occurs on these drugs. Like with coffee and people dependent on caffeine GRADUALLY over a long period of time their brains normal state develops an impaired ability to concentrate and focus. Many neurologists say that amphetamine derivatives* like adderall, pervitin, and amphedroxyn should not be taken for longer than a year.
Federer does not show absent mindedness nor various memory impairments that gradually develop from heavy caffeine dependency or amp-derivate* use.