W38 – Delusions, Unusual Beliefs, and Conspiracy Theories: Has the Boundary Shifted?

W38 – Delusions, Unusual Beliefs, and Conspiracy Theories: Has the Boundary Shifted?

Saturday, Oct. 29
10:45 – 11:45 (1 hr)
Meeting Room: Birchwood Ballroom (Mezzanine)
Gary Chaimowitz*, MBChB, FRCPC, FCPA; Joseph Ferencz, MD, FRCP

CanMEDS Roles:

  1. Medical Expert
  2. Professional
  3. Scholar

At the end of this session, participants will be able to: 1) Have a better understanding of how certain political movements have challenged the diagnosis of delusions; 2) Have an improved awareness of the extent of bizarre ideation present in certain segments of the population; and 3) Appreciate the need to distinguish delusions from certain bizarre mass-held belief systems.

The accurate diagnosis of delusions, whether they be isolated or one of many symptoms of severe mental illness present in an individual, can have many important implications. Accurate diagnosis can have important prognostic, risk, and medico-legal implications. The distinction between delusions and firmly held beliefs has often been unclear. In the case, for example, of delusional disorder, preserved function and a relative absence of other psychiatric symptoms can make the diagnostic process particularly challenging. The widespread dissemination of and acceptance of poorly supported ideas and beliefs has been accelerated in recent years by social media outlets. This has resulted in a plethora of unusual, at times bizarre, beliefs or conspiracy theories, being widely held within the general population. This has added a layer of complexity to an already difficult task.

In this workshop the process of assessing and diagnosing people with delusional ideation will be reviewed, with particular emphasis on the diagnosis of delusional disorder. Specific interview techniques and psychological testing approaches will be discussed. Some of the limitations of the current DSM approach to the diagnosis of these disorders will be reviewed. Key discriminating features that will assist in distinguishing unusual, but culturally sanctioned, beliefs held by large numbers of people in society from the delusional ideas of people with severe mental illness will be presented. The continuum versus category debate will also be highlighted. Clinical cases demonstrating these issues and the ways in which they can be addressed will be described and discussed.


  1. Mullen R. Delusions: the continuum versus category debate. Aust N Z J Psychiatry 2003;37:505–11.
  2. Hoff P. Delusion in general and forensic psychiatry–historical and contemporary aspects. Behave Sciences and the Law 2006;24:241–55.