It seems I might have been on the money when I asked about pilots seeing doctors secretly a few hundred posts ago
http://www.pprune.org/8919671-post1537.html This practice is almost impossible to stop. Mandatory reporting won't prevent a pilot from seeing a doctor privately, perhaps in another country, and pretending to be a bus driver. Perhaps this tragedy will lead to calls for frequent blood testing to detect prescription drugs?
Given the pressure that pilots are under I would be amazed if there are not a great many who systematically deceive their employer about their health. It sounds like the job is becoming impossibly demanding, with the rewards disappearing through the floor. You guys and gals have my sympathy.