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A delusion is commonly defined as a false belief, and is used in
everyday language to describe a belief that is either false, fanciful
or derived from deception. In psychiatry, the definition is necessarily
more precise and implies that the belief is pathological (the result
of an illness or illness process).
Delusions typically occur in the context of neurological or mental
illness, although they are not tied to any particular disease and
have been found to occur in the context of many pathological states
(both physical and mental). However, they are of particular diagnostic
importance in psychotic disorders and particularly in schizophrenia.
Psychiatric definition
The psychiatrist and philosopher Karl Jaspers first defined the
three main criteria for a belief to be considered delusional in
his book General Psychopathology. These criteria are
- certainty (held with absolute conviction)
- incorrigibility (not changeable by compelling counterargument
or proof to the contrary)
- impossibility or falsity of content (implausible, bizarre or
patently untrue)
These criteria still live on in modern psychiatric diagnosis.
In the most recent Diagnostic and Statistical Manual of Mental Disorders,
a delusion is defined as:
A false belief based on incorrect inference about external reality
that is firmly sustained despite what almost everybody else believes
and despite what constitutes incontrovertible and obvious proof
or evidence to the contrary. The belief is not one ordinarily accepted
by other members of the person's culture or subculture (e.g. it
is not an article of religious faith).
Primary and Secondary Delusions
Jaspers originally made a distinction between primary and secondary
delusions.
According to Jaspers, primary delusions (sometimes called true
delusions) are distinguished by a transformation of meaning, so
that the world, or aspects of it, are interpreted in a radically
different way by the delusional person. To others, this interpretation
is 'un-understandable' in terms of the normal mental causality,
mood, environmental influences and other psychological or psychopathological
factors.
Read more about Primary Delusion from Jaspers' point of view. |
