Basically, the civilian equivalent of PTSD. Some will be unable to enter downtown Boston, others may find themselves unable to enter any urban areas. Every paper bag on the street, a lost backpack sitting in a coffee shop will call up the memories. There will be attacks on the innocent simply because they "talk funny" or wear strange clothes or have skin that is just a bit darker than 'normal'.
On Facebook this morning are photographs that supposedly show "suspects" on roof tops near the finish line of the marathon but other photos show the 'suspects' were actually police guarding the area.
We just don't know enough at this point but people like Alex Jones are stirring the pot already with his claims of "false flag operation" as an excuse for the "Communist in the White House" to overthrow our Constitutional government.
It is difficult to step back and think rationally at times of great tragedy but we must do it. Fear of the 'other' far too often causes more harm than good.