Maria Sharapova's failed drugs test is a "game-changer for life, not just for tennis", her former coach says.
Nick Bollettieri also told the BBC he was shocked the former world number one had tested positive because "she has always been above board in everything".
But the 84-year-old American added: "Everybody must accept responsibilities for everything they do in life."
Sharapova, 28, has taken meldonium for health reasons since 2006, but it became a banned substance in 2016.
The Russian revealed she tested positive after losing to Serena Williams at the Australian Open in January.