Definition
Paranoia is a symptom in which an individual feels as if the world is "out to get" him or her. Paranoia causes intense feelings of distrust, and can sometimes lead to overt or covert hostility.
Description
The hallmark of paranoia is a feeling of intense distrust and suspiciousness that is not in response to input from anybody or anything in the paranoid individual's environment.
Causes of paranoia
Paranoia is often manifested as part of the symptom complex of schizophrenia. In fact, one of the subtypes of schizophrenia is termed "paranoid schizophrenia," which actually refers to a type of schizophrenia in which the individual is particularly preoccupied with delusions in which the world seems to be pitted against him or her. As with other forms of schizophrenia, sufferers often lack contact with reality, and display hallucinations, flat or emotionless affect, and disorganized thinking and behavior.