Is drug addiction considered an injury?

I guess it depends on how you got addicted.

The question is pretty broad to provide much guidance for. Having said that, if the drug addiction stems from the treatment of injuries you suffer as a result of someone else's negligence, it may be a compensable injury. In addition, proving that the drug addiction was a foreseeable result of any such negligence would likely be necessary to prove as well. If this drug addiction does come from the treatment of injuries you suffer as a result of someone else's negligence, call an injury attorney to discuss the matter. Usually, a phone call to an injury attorney won't cost you anything. Always remember, there may be a statute of limitations that applies to your case. Failure to take appropriate legal action in the time allotted can result in the dismissal of your case.

It is not considered an injury, but can be considered a part of the injury claim in the right circumstances. For instance, if a victim is being treated for pain and becomes addicted to prescribed pain medication.

No, but under the right circumstances it could be considered the consequence of an injury.

No, not unless it stems from the underlying treatment of another injury [taking pain pills for a back injury].

That all depends on whether the drug's addicted to were prescribed or purchased illegally.

Might be, but more generally not.