A delusional system is a set of symptoms in relation to having chronic false beliefs. Karl Jaspers, a German-Swiss psychiatrist, specified that a delusional system is the result of the development of psychotic patients’ thought processes. (In DSM 5, such unreal convictions should have been persisting for at least a month in order for a diagnosis of delusional disorder to be made.) For instance, a patient is convinced that the president is in love with her. Her delusional system includes her conviction that the president is sending her secret messages whenever he is giving a speech on TV and her unwavering expectation that they are going to get married in the near future.