While the study looked at depression, rather than anxiety, Toronto's Sunnybrook Hospital did an interesting study on TBI and SSRIs. sunnybrook.ca/media/item.asp?c=1&i=258

Published in the November 2008 issue of the Journal of Psychopharmacology, it is the largest study on SSRIs in the treatment of major depression following TBI - and the only one NOT funded by the drug companies.

I feel it's good to read research that is peer reviewed, independent and based on larger samples. Maybe the link should be in our sticky.

Anyway, I second Mark's advice of treating the anxiety when it appears, rather than being medicated constantly as a preventative. You might also want to talk to a psychologist about techniques (breathing, visualization, etc...) that might help abate your symptoms.

Hang in there.