[ellery]

This raises an interesting question. I posit that drug use becomes addiction when the cost of doing it exceeds the benefit. People who are on diabetes medications for life, or even lifetime, maintenance-level pain medications like oxycontin, could be said to be addicted -- but I wouldn't include them in that category. I suspect that Rush realized he was addicted at the point where he saw that the drugs were having a more negative effect on his life (e.g., the need to hide the quantity, or the need to buy illegally, etc.,) than the pain he originally took drugs to fix.

[weegee]

It may not have been a need for increased quantity. Maybe the doctor's prescription levels were being monitored and it could red flag him. He tells Rush that he can't continue prescribing him Oxycontin. Alternatively he may tell Rush that he is concerned about longterm problems with withdrawl from Oxycontin and is only willing to prescribe it to him for a short period (after which Rush goes to alternative avenues after finding it works better than other medications).