In this case, the person views others as the cause of their personal difficulties in order to preserve a positive self-view.This condition is more common among people who have poor hearing or sight. Also, ongoing stressors have been associated with a higher possibility of developing delusions. Examples of such stressors are immigration, low socioeconomic status, and even possibly the accumulation of smaller daily hassles. Specific delusions
The top two factors mainly concerned in the germination of delusions are disorder of brain functioning and background influences of temperament and personality.Higher levels of dopamine qualify as a symptom of disorders of brain function. That they are needed to sustain certain delusions was examined by a preliminary study on delusional disorder (a psychotic syndrome) instigated to clarify if schizophrenia had a dopamine psychosis. There were positive results - delusions of jealousy and persecution had different levels of dopamine metabolite HVA and homovanillyl alcohol (which may have been genetic). These can be only regarded as tentative results; the study called for future research with a larger population. It is simplistic to say that a certain measure of dopamine will bring about a specific delusion. Studies show age and gender to be influential and it is most likely that HVA levels change during the life course of some syndromes.On the influence of personality, it has been said: "Jaspers considered there is a subtle change in personality due to the illness itself; and this creates the condition for the development of the delusional atmosphere in which the delusional intuition arises.
Persecutory delusions
Persecutory delusions are the most common type of delusions and involve the theme of being followed, harassed, cheated, poisoned or drugged, conspired against, spied on, attacked, or otherwise obstructed in the pursuit of goals. Persecutory delusions are a condition in which the affected person wrongly believes that they are being persecuted. Specifically, they have been defined as containing two central elements: The individual thinks that:

harm is occurring, or is going to occur
the persecutors have the intention to cause harmAccording to the DSM-IV-TR, persecutory delusions are the most common form of delusions in schizophrenia, where the person believes they are "being tormented, followed, sabotaged, tricked, spied on, or ridiculed". In the DSM-IV-TR, persecutory delusions are the main feature of the persecutory type of delusional disorder. When the focus is to remedy some injustice by legal action, they are sometimes called "querulous paranoia". Causes
Explaining the causes of delusions continues to be challenging and several theories have been developed. One is the genetic or biological theory, which states that close relatives of people with delusional disorder are at increased risk of delusional traits. Another theory is the dysfunctional cognitive processing, which states that delusions may arise from distorted ways people have of explaining life to themselves. A third theory is called motivated or defensive delusions. This one states that some of those persons who are predisposed might experience the onset of delusional disorder in those moments when coping with life and maintaining high self-esteem becomes a significant challenge.