What is paranoid behavior disorder?

Suspiciousness : Paranoia can be mild to severe and can be a symptom of a mental disorder. There can be a distrust and suspiciousness of others or delusions that someone is intending harm to oneself. Paranoia can also be an unwanted side effect of marijuana intoxication. Paranoia can influence a person to behave as if the suspicions or delusions are true. Such behaviors might not be appropriate to the situation.