According to the Associated Press's Rachel Zoll, the U.S.'s Roman Catholic bishops are holding a conference on how to conduct exorcisms (link above). It seems there's a "...shortage of priests who can perform the rite..." so there will be a conference on how to conduct same.
Is this the 13th century?
According to Zoll, "Signs of demonic possession accepted by the church include violent reactions to holy water or anything holy, speaking in a language the possessed person doesn't know, and abnormal displays of strength.
"The full exorcism is held in private and includes sprinkling holy water, reciting Psalms, reading aloud from the Gospel, laying on of hands and reciting the Lord's Prayer. Some adaptations are allowed for different circumstances. The exorcist can invoke the Holy Spirit, then blow in the face of the possessed person, trace the sign of the cross on the person's forehead, and command the devil to leave."
So if you have a "...violent reaction to holy water or anything holy" the remedy is "...sprinkling holy water, reciting Psalms, reading aloud from the Gospel, laying on of hands and reciting the Lord's Prayer?"
How about we just eliminate the cause instead? I suspect there might not be a need for exorcisms if there weren't a church to judge ones' "evil spirit."