Two types of RAD?

Something Kerry wrote in a blog reaction: "RAD is the result of inconsistent care given to ANY child within the first three years of life."

As far as I can understand the neurobiology, RAD finds it's origins in the incomplete development of certain hormone receptors in the brain of a child prior to the age of three. Once past that age, the damage is deemed irreversible, as the growing body 'moves on' to different tasks.

That bit makes sense to me, although the implication would be that no form of therapy can help. However, what about the people that had a 'normal' early childhood, but who's RADdish behaviour was caused by later stress factors (various forms of abuse come to mind - I never cease to be amazed at the horrors people are capable of)?

Wouldn't that imply that when the 'hardware' foundation is there (i.e. the hormone receptors), in principle some form of therapy should be able to provide 'healing'? The relevance being that it would be vitally important to retrace the origins of an individuals RAD behaviour as, depending on how far back it goes, therapy could either be useful or useless. I'd be very interested in your thoughts on this.