I think it obvious personally - you would find it difficult to find an anaestiologist who fears the drugs. Also notably the reason you heard about it was because the hammer of the state, not because the drugs itself ruined his life.
I generally agree about the hammer of the state angle, but another angle here is that if medical people are addicted to drugs and they have access to patients' drugs, they can potentially skim some of the drugs that they're supposed to be giving their patients.
