In many situations, a person who is injured receives treatment longer than expected. This is very common when people are taking prescriptions or pain medications for long periods of time. There can be many reasons: dependence, addiction, misdiagnosed causation, driving up claims costs for settlement, etc.
One that is not often explored is the street value of the drugs. Reselling prescriptions provides many people an additional income stream. Here’s a great article on the subject.
It’s important to have systems and indicators in place to watch for these patterns before they get out of control.