Joe,
I understand your question. I wasn’t posting what I wrote in response to your earlier post that “most anxieties are rooted in real life occurrences, the irrational part is the association later on to other events”. I was responding to PBA’s original post which was talking about any anxiety.
However I still tend to disagree with you. As you yourself put it originally, “the irrational part is the association later on to other events” – his current feelings are bottom line irrational. The explanation the psychologist will give may be a rational explanation, in that we can understand how such an anxiety could develop. But that doesn’t mean that the fear itself is rational. So I think Bitochon on a high level would sort out the anxiety even here (though I’m not sure and can’t prove this from the Mesilas Yeshorim).
Having said that, it wasn’t my intention to belittle the psychological methods of resolving anxiety (with which I’m not familiar). Achieving a high level of Bitochon is no easy task, and although it would be better to resolve the anxiety this way, often the psychologists’ way is simpler to achieve results. So I agree with your final point that all these steps are helpful.