Mass hysteria certainly did play a large part in the tragedy which hit Salem during the witch trials (as depicted in Arthur Miller's play The Crucible). The behavior of the girls, led by Abigail, were ones which the community (at large) could not understand. Like today, when someone does something that another does not understand fear breaks out. For Salem, this was no different.
For quite a while before the accusations began to fly, the citizens of Salem had very deep seeded problems with others in the community. The fact that the questioning of certain behaviors began to rise gave them the opportunity to raise concerns of their own.
Unfortunately, for many, the dealing with the unknown came to be the lead of the hysteria which broke out. Fear, and anger/hate, tends to be an emotion which normally takes on a life of its own. Therefore, the hysteria which broke out was the main element which fueled the witch trials.