Research findings by Blackwood et.al. (2004) and Moller & Husby (2000) have argued that delusional thinking is often related to a heightened tendency of focus upon the self, things related to and/or reflecting on the self. From this example it would appear that unusual or unlikely beliefs have a significant impact on an individual’s personal views and beliefs in everyday reasoning.
According to the DSM-IV (2005), delusional ideation is one of the symptoms of schizophrenia. The presence of `delusions` is one of the most important concepts used by psychiatrist and psychologists to diagnose patients who are considered to have lost touch with reality (Maher, 1988).
David (1999, p.17) suggested ‘there is no acceptable (rather than accepted) definition of delusion’. However, American Psychological Association (DSM-IV, 2005) formulated a definition of a delusion as a false or incorrect reference about external reality that appears different from what everyone else believes.
Several studies revealed that biological relatives of schizophrenic individuals are more likely to display schizotypic psychopathology (Kendler, 1985).
This might be due to genes (e.g. abnormalities involving cortical-subcortical circuitry) and/or environmental factors (e.g. modelling schizophrenic behaviour, triggers within the environment – DSM-IV, 2005).
It was proposed that psychotic symptoms displayed by the mentally ill individuals are extreme versions of everyday behaviour (Claridge, 1988 Claridge & Beech, 1995). At one end of the spectrum lies normal healthy cognition and behaviour, at the opposite end lies the characteristics of mental ill health. This was argued by the proponents of continuity model of mental illness (e.g. Claridge, 1998; Claridge & Beech, 1995; Linney, Peters & Ayton, 1998).
Furthermore, research evidence shows that schizotypal traits are present within the general population. These schizotypal tendencies are commonly assessed using self-reported (subjective) measures such as schizotypy questionnaires (e.g. Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE); Mason, Claridge & Jackson, 1995; the Peters et. al. Delusions Inventory (PDI) Peters, Day & Garety, 1996).
This has enabled researchers to investigate some of the traits associated with schizophrenia within the healthy population and symptoms can be measured psychometrically, the questionnaires showing some success in studies of subclinical delusional ideation.
Studies revealed there were more people with delusional ideation in general population than expected but these cases are not extreme enough to be classed as mental illness. This subclinical category of experience is referred to as schizotypy (Meehl, 1962, 1990, Claridge, 1998) and is defined by behaviour that is neither obviously odd nor bizarre (DSM-IV, 2005).
The nonbizarre delusions involve situations that in principle could occur in real life (e.g being persecuted, deceived by a spouse or lover, belief in occultism, grandiose feelings etc.) and are experienced by the individual that sees them as vivid events that take place in real life and can result in marital, social and/or work-related problems (DSM-IV, 2005).
Huq, Garety and Hamsley (1988) found that patients who experience delusions often exhibit a reasoning bias. Using a probabilistic reasoning problem known as the ‘beads’ task, Huq, Garety and Hamsley (1998) concluded that patients high on delusional ideation tended to make decisions on the basis of less evidence when compared to non-deluded (subclinical) participants.
In the `beads` task study, participants were shown two jars of coloured beads, informed of the relative proportions of beads in each, then told that they will be shown a series of beads drawn from one of the jars. Subjects were then asked to judge which jar is the source of the beads.
Huq et. al. found that delusional patients tended to request fewer beads than non-delusional participants before making a decision, displaying a `jumping to conclusions` reasoning style which may be associated with intolerance of uncertainty. This has led Dudley et. al. to suggest a data-gathering bias rather than a reasoning deficit which may underline the tendency towards the development of delusional ideation (abnormal beliefs).
In a UK survey dating from 1998, it was revealed that a large number of the population held `uncommon` (or without a rational explanation) beliefs. The survey reported: 41 percent of participants believed in communication with the dead, 49 per cent believed in heaven, and interestingly – only 28 per cent believed in hell (Survey for Paranormal Beliefs, 1998).
Within these studies a significant difference was reported between genders. Female representatives were found to score higher than males on magical thinking and other schizotypal features (Claridge and Hewitt, 1987).
Many of these studies reveal a cultural difference in held beliefs, Western countries having large numbers of believers in god(s) and other paranormal beliefs (Taylor, 2003). These beliefs were reported to be experienced as visual, auditory or kinaesthetic, an example being sightings of St. Mary, figure of Christianity, in several locations around the world.
Moreover, these everyday beliefs people develop regarding controversial subjects such as the once used in the current study (e.g. the existence of ghosts; capital punishment; the right to smack your own children; that reincarnation is real; allowing asylum seekers into the country; the war on terror; research on animals; the existence of aliens; euthanasia; national service) can be viewed as a political issue, social psychology (Billig, 1987), conformity, obedience to authority or biased rationalisation of events that might affect directly the attitudes towards life of many.
Galbraith, Manktelow & Morris (2008) designed a study of subclinical delusional ideation and a self-reference bias in everyday reasoning and findings from this study seem to indicate that individuals with high delusional ideation rated self-referent objections as stronger than other-referent objections, this indicating that individuals with subclinical delusional ideation exhibit a self-reference bias when engaging in everyday reasoning.
Do you consider delusional ideation to be a ‘normal’ everyday aspects of human existance?
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