This topic has been in the news lately due to a high profile Sydney neurosurgeon who was caught in possession of cocaine at a nightclub in the Gold Coast. The neurosurgeon in question is actually one who is regularly used by high profile athletes in Sydney for spine injuries and has a great reputation as a surgeon.
It is a bit of an extrapolation to suggest that this particular surgeon is "addicted" to drugs as he was only caught in possession, meaning he may be an infrequent user. However, he did plead guilty and therefore he must at the very least be an infrequent user of this party drug or he would have contested the charge.
There is a good article on the Health report on this topic:
Another interesting question is: should GPs continue to refer to this doctor in the future (given past results were satisfactory)?
The argument against suggests that as an illegal drug user he may be impaired in judgement somewhat. However, he is unlucky to have been caught but perhaps not the only surgeon to have ever used cocaine. He also works in a profession where numbers are very limited, with many surgeons steering away from neurosurgery due to liability premiums.