I think this word in verse 8 is referring back to verse 5 where it says they were "made alive" or "quickened" depending on what version you use.
That's a resurrection - well, a figurative one anyway. Still, a resurrection is a type of healing.
Also, the Greek word used there is translated as 'healing' in most other spots in the KJB, so why not here too?
-Jarrod
The reason is in the overall usage of Paul. Salvation has two present-life aspects, the legal and the transformational. The legal (justification) is about past sin-as-debt. To be in Christ is to gain his righteousness as an infinite credit toward that debt so that we don't stink of guilt when we function of life.
The 2nd is personal transformation which is motivated or driven by justification.
The 4 doctrinal letters (Gal, Eph, Phil, Col) are an interesting study on the creative re-expression of justification. Gal is not actually re-expression, but not as much detail as its 'parent' letter, Romans, which is very detailed. Eph uniquely refers to salvation without using the legal term. Phil mentions the justifying righteousness of Christ in ch 3 as so necessary that all of Paul's life in Judaism was rot. Col is the most intriguing in that the opponents (sort of neo-Judaism) have declared that believers are dis-justified until they practice Judaism. Obviously Paul could not say that unless justification was by Christ a alone.
There is of course a soundness of mind from salvation, but he himself got no relief from his 'thorn in the flesh' did he? Dr. Schaeffer (L'Abri) would call this soundness of mind 'a substantial psychological healing' as something apart from what we might call medical. We see the features of it in the end of ch 3:
*a belief in one god for all
*an affirmation of the morality of the Law
*the end of boasting
At the beginning of ch 5 there is more:
*the peace mentioned here is about our debt account; I believe reconciliation is often meant in the accounting sense, as in v11 (notice that we passively receive it vs we were part of providing it)
*to live in grace
*to 'boast' in the hope of God's glory (rather than our own!), see a 2nd hope below
*perseverance
*proven character
*a certain amount of hope within us through proven character
All these things are indeed substantial psychological healing, but not the medical sense of things like blindness or paralysis.