Can docs please explain are cortico steroids addictive?

No, they are not: However, when people are on cortisone-like drugs (decadron, prednisone, medrol) on sufficient doses for a long enough time (more than 2-3 weeks), the steroid needs to be gradually withdrawn. This is NOT addiction. It is because the adrenal glands stop making our own cortisone, and it takes time for it to recover that function. Stopping suddenly can be medically dangerous.

Not in the usual way: However, they can lead some to an improved sense of well being and can be associated with depression upon cessation. While this is much more true for testosterone like drugs, I have seen it with prednisone and medrol (methylprednisolone).