Hello, Sam, and welcome.
In my view, it would never be appropriate to administer a narcotic to relieve depression. For one thing, it would only mask the problem and never get to the real basis for the depression which needs to come out so that you may heal.
It is true that depression can cause physical pain, but even then the best method of correction is medication for depression, not the use of narcotics. Narcotics destroy brain cells, just as surely as alcoholism does. I don't know how you feel about it, but I need every one I've got.
Take care and please continue the appropriate treatment for depression: psychotherapy, medication, diet corrections., and exercise.