Delusion

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).

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Jaspers originally made a distinction between primary and secondary delusions.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. Jaspers describes four types of primary delusion:

~ ~ ~ ~ ~ ~ ~ ~ ~ ~

• delusional intuition - where delusions arrive 'out of the blue', without external cause.
• delusional perception - where a normal percept is interpreted with delusional meaning. For example, a person sees a red car and knows that this means the person's food is being poisoned by the police.
• delusional atmosphere - where the world seems subtly altered, uncanny, portentous or sinister. This resolves into a delusion, usually in a revelatory fashion, which seems to explain the unusual feeling of anticipation.
• delusional memory - where a delusional belief is based upon the recall of memory or false memory for a past experience. For example, a man recalls seeing a woman laughing at the bus stop several weeks ago and now realises that this person was laughing because the man has animals living inside him.

Secondary delusions (sometimes called delusion-like ideas) are considered to be, at least in principle, understandable in the context of a person's life history, personality, mood state or presence of other psychopathology. For example, a person becomes depressed, suffers very low mood and self-esteem, and subsequently believes he or she is responsible for some terrible crime which he or she did not commit.

~ ~ ~ ~ ~ ~ ~ ~ ~ ~