DD is also known as psychosis or paranoid disorder and persists for at least one month (Bustillo, 2008).
DD may be related to the patient’s life history or his experiences in the past and is seen in elder people normally who combine it with auditory hallucinations. However, DD patients do not show any abnormal or bizarre behavior when they socialize.
DD is of various types depending upon the kind of delusions being experienced by the patient. According to the Encyclopedia of Mental Disorders (2010), these types include Erotomanic (the patient has the delusion that someone famous is in love with him which may cause the patient to stalk him); Grandiose (the patient thinks that he has great abilities that make him better than others); Jealous (the patient thinks that his partner is betraying him); Persecutory (where the person thinks that he is being spied or harrassed); Somatic (the patiemt thinks that he has some physical abnormality); and, Mixed (the patient may show multiple types of DD).
Research has shown that DD patients do not act strange or weird when they are being social, and this is what makes this disorder different from other psychotic disorders (Schultz & Videbeck, 2008, p. 174). Unless the patient himself discusses the problem with the healthcare professionals, it is very difficult to tell whether a person is suffering from DD or not. However, the patient is apt to make choices and decisions depending on his delusions which he may not make otherwise. For example, if he believes that his spouse is betraying him, he may choose not expand his family which is a choice he would not have made otherwise.
Another reason why DD are not obvious is that a DD patient sometimes holds so strong opinion that he does not even think that he is wrong in believing what he think is true no matter how troubled he feels about the situation (Sedler, 1995). Instead of detecting