I recently came across an article and book which may be of interest?
The article,
10 Steps for Parents and Kids to Tame the Worry Monster Daniel B. Peters, Ph.D. on Huff Post Parents, discusses anxiety. Interested readers can sign up to receive updates from the author.
The newly released book,
Make Your Worrier a Warrior, (2013, Great Potential Press) authored by Daniel Peters Ph.D., lends expert insight to understanding what a child may be experiencing. For example, pages 44-45 suggest that parents may wish to think of acting out as
a variation of the "fight or flight" response... children couldn't articulate their fears... they were reacting behaviorally because their amygdala, or their emotional brain, was overriding their thinking brain... kids often do not have the emotional vocabulary and/or insight to tell you what is going on...
Armed with this knowledge, working on helping a child understand nuances of feelings and vocabulary to express their interpretation of what they are experiencing, may prove helpful.
ETA: There is also a teen/tween version of the book
From Worrier to Warrior, A Guide to Conquering Your Fears, (2013, Great Potential Press) authored by Daniel Peters Ph.D.
