To answer your question everyone is susceptible to paranormal activity. The only thing that interoperates these events is our brain. Commonly an individual will divide "right" from "wrong," or "good" from evil." Thus leaving themself with an answer to the "paranormal activity" experience. Generally these experiences are foreign to the individual(s) involved, which leads them to believe that the experience is from an evil source.
It is not uncommon for entities, whether living, dead or undead to commune with an individual in any means possible to get their attention. There are two ways to deal with these types of occurrences;
1. If you are a non believer of the eternal soul than simply ignore this experience, or attempt to scientifically explain the event.
2. If you are a believer and you have excepted that this event has happened either consciously or unconsciously, than it is your best interest to understand that you are in power of your own vessel/body. There is no reason for you to fear harm from any entity unless you have accepted that they are stronger/more powerful than you.
I hope this helps...