I have been diagnosed with delusional disorder. I believe I have been under surveillance by my former employer, the law firm of Akin, Gump, Strauss, Hauer & Feld. My belief system has been described by psychiatrists as a fixed delusional system of longstanding duration.
But according to the literature delusional disorder entails more than false beliefs about one's environment. Studies of people with the disorder show that there are specific cognitive impairments associated with the the disorder.
For example, people who have the disorder have specific difficulty performing on the Wisconsin Card Sorting Test (WCST). Interestingly, I took the WCST in 1996 and I scored one of the lowest possible scores: six nonperseverative errors. I made no perseverative errors on the test, which people with delusional disorder tend to do. My results were consistent with "high concept formation ability." The testing was performed at the George Washington University Medical School Department of Psychiatry by a resident named Ramin Mojtabai, MD under the supervision of staff psychologist Robert Jenkins, Ph.D.
People with delusional disorder have also been shown to have difficulty understanding metaphors. I don't think I have that problem.
I wonder if I really have delusional disorder?
Here's one research study that demonstrated the cognitive impairments associated with the disorder:
Isabel Boemmer and Martin Bruene, "Social cognition in 'pure' delusional disorder." Cognitive Neuropsychiatry, Volume 11, Issue 5 September 2006 , pages 493 - 503
Introduction. Delusional disorders are characterised by monothematic, “encapsulated” and incorrigible false beliefs and misinterpretations of social signals. Due to the rarity of cases with “pure” delusional disorder (DD) in clinical settings most studies of social cognition in delusional patients have focused on patients with paranoid schizophrenia. In the present study we sought to examine emotion recognition, theory of mind abilities, and pragmatic language comprehension in patients with delusional disorder.
Methods. Social cognition was assessed in 21 patients recruited over a 3-year period who were diagnosed with delusional disorder, paranoid, erotomanic, or jealous type. In addition to an emotion recognition and theory of mind test battery, we included a novel German Proverb Test, which has been found indicative of subtle theory of mind deficits in schizophrenic patients. Executive functioning was assessed using the Wisconsin Card Sorting Test (WCST). Psychopathology was measured using the Positive and Negative Symptoms Scale (PANSS). Patients' task performance was compared to a group of 22 healthy control persons paralleled for verbal intelligence, education, and age.
Results. Patients with DD made significantly more perseverative errors in the WCST, they performed more poorly on the theory of mind tasks and the proverb test, but were unimpaired in basic emotion recognition abilities relative to controls. When executive functioning was co-varied out, the group differences in theory of mind disappeared, whereas the greater propensity of patients with DD to interpret proverbs literally remained significant.
Conclusions. In “pure” DD the basic social cognitive abilities appear to be preserved. Difficulties in metaphorical speech comprehension and executive functioning could, however, indicate more subtle social cognitive deficits in these patients.