Religion and Spirituality in Psychiatry

86 Sylvia Mohr and Samuel Pfeiferbeen shown that 10 to 28 percent of the generalpopulation have delusions (depending on thebroadness of criteria), whereas the prevalenceof psychosis varies around 1 percent.(34, 35, 36)This leads us to consider delusions not as discretediscontinuous entities, but as a complex andmultidimensional phenomenon. Assessing thepresence of a delusion may then best be accomplishedby considering a list of dimensions, noneof which is necessary nor sufficient, but which,when adding one to the other, result in greaterlikelihood of a delusion. For instance, the moreimplausible, unfounded, strongly held, not sharedby others, distressing, and preoccupying a beliefis, the more likely it is to be considered a delusion.(37) Although the number and the nature ofdimensions vary across studies, the most commondimensions are conviction, preoccupation,pervasiveness, negative emotionality, and actioninaction.(38)When comparing delusions in depression andschizophrenia, the criterion mood- congruent versusmood-incongruent delusional beliefs appearsas a specific dimension, “incongruence withaffective state.” The other dimensions are behavioraland emotional impact of delusional beliefs,cognitive disintegration, delusional certainty, andlack of volitional control. Delusions in depressiondisplay the same severity as delusions in schizophreniawith regard to delusional certainty andbehavioral and emotional impact.(39)Th e Peters Delusions Inventory (PDI) questionnairewas created to investigate delusionsin general and in psychiatric populations.(40)This scale scans for a set of beliefs, questioningif people hold them and how much they areconvinced, worried, and distressed by them.Those beliefs were mainly drawn from the symptomslist of the Present State Examination (22)and the Schneiderian’s first rank symptoms ofschizophrenia.(41) Several studies have beenconducted with this scale, comparing delusionalideations in healthy and psychiatric populations.For example, in a study of primary-care patientswithout lifetime history of psychiatric disorder,the range of delusional beliefs ranged from 5percent to 70 percent.(42) Of course, comparedto deluded psychiatric inpatients, healthy adultsappeared to endorse fewer of those beliefs and tobe less distressed, preoccupied, and convinced.Nevertheless, it is important to acknowledge thefact that, on average, healthy adults endorsedone-third of those delusional beliefs. Moreover,11 percent of healthy adults endorsed moredelusional beliefs than deluded psychiatricinpatients.(43) One study of particular interestis the comparison between deluded psychoticin-patients, new religious movements’ members(Hare Krishnas and Druids), and two controlgroups (nonreligious and Christian). The newreligious movements’ members endorsed asmuch delusional ideation as psychotic patients,with the same level of conviction , but with levelsof preoccupation and distress similar to the controlgroups.(40)Another way to tackle this is to differentiateinitial beliefs that are directly linked to observationand theoretical beliefs based on introspectionand judgments. By comparing delusionsamong inpatients with schizophrenia and thereligious belief (“God exists”) of highly religiousChristians acting as a control group, it appearedthat the religious beliefs and delusions did not differon levels of conviction, falsity, affect, nor influenceon behavior.(44) Those studies point out thatassessing the contents of beliefs is of little use todifferentiate religious beliefs from delusions.2.3.1. Formation and Conservationof DelusionsAnother approach to better understand delusionsis to focus on their formation and conservation.Three types of theoretical models tryto explain the formation of delusions based,respectively, on motivation, cognitive deficit,and perceptual anomalies. Theories based on themotivation view of delusions suggest that theyhave a defensive, palliative function, being anattempt to relieve pain, tension, and distress. Inthis view, delusions provide a kind of psychologicalrefuge and are understandable in terms of theemotional benefits they confer.Theories based on the deficit view of delusionsargue that they are the consequence of