Dimensions and classes of psychosis in a population cohort: a four-class, four-dimension model of schizophrenia and affective psychoses

Murray, V.; McKee, Ian; Miller, Patrick; Young, David; Muir, Walter; Pelosi, Anthony; Blackwood, Douglas

doi:10.1017/s0033291704003745

Cited by 69 publications

(60 citation statements)

References 60 publications

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“…The 5 symptom dimensions reported in the present study agree with the findings from factor analyses in patient samples. 25,26 Although others have reported a 4 instead of a 5-factor solution [27][28][29] , this is mainly due to difficulties in separating the negative and disorganization dimensions. 30 Previous studies on subtypes of psychotic disorder have identified more psychotic clusters than we report in our study 8,[31][32][33] , although there is agreement with the class solution presented here.…”

Section: Discussionmentioning

confidence: 98%

Kraepelin Was Right: A Latent Class Analysis of Symptom Dimensions in Patients and Controls

Derks

Allardyce

Boks

et al. 2010

Schizophrenia Bulletin

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Section: Discussionmentioning

confidence: 98%

Kraepelin Was Right: A Latent Class Analysis of Symptom Dimensions in Patients and Controls

Derks

Allardyce

Boks

et al. 2010

Schizophrenia Bulletin

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“…Factor scores have the potential advantages of being pseudo-continuous and allowing symptom weightings. However, in our view, these were outweighed by OPCRIT factor scores being highly dependent on which symptoms are included and having complex solutions that vary between samples [Cardno et al, 1997[Cardno et al, , 1999a[Cardno et al, , 2001Serretti et al, 2001;Murray et al, 2005;Dikeos et al, 2006], causing problems for interpreting and replicating results. Additionally, the phenotypic properties of symptom score dimensions have been investigated in detail in this sample [Cardno et al, 2008], and are more convenient when adjusting for ascertainment and assessing inter-rater reliability.…”

Section: Limitationsmentioning

confidence: 90%

“…Dimensional phenotypes often include more than two items/ symptoms but, in this particular context, the results of factor analyses are clearer and more consistent for small numbers of broad psychotic symptoms [Liddle, 1987;Andreasen et al, 1995;Peralta et al, 1997;Ratakonda et al, 1998] than larger numbers of symptoms [Cardno et al, 1997[Cardno et al, , 1999a[Cardno et al, , 2001Serretti et al, 2001;Murray et al, 2005;Dikeos et al, 2006], and within-pair correlations reduce as further symptoms are added to those analyzed here [Cardno et al, 2008].…”

Section: Limitationsmentioning

confidence: 99%

Heritability estimates for psychotic symptom dimensions in twins with psychotic disorders

Rijsdijk

Gottesman

McGuffin

et al. 2010

American J of Med Genetics Pt B

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Factor analysis of psychotic symptoms frequently results in positive, negative, and disorganized dimensions, but heritability estimates have not yet been reported. Symptom dimensions are usually only measured in individuals with psychotic disorders. Here, it is valuable to assess influences acting via liability to psychosis and independent modifying effects. We estimated heritability for psychotic symptom dimensions, taking account of these issues. Two-hundred-and-twenty-four probandwise twin pairs (106 monozygotic, 118 same-sex dizygotic), where probands had psychoses, were ascertained from the Maudsley Twin Register in London (1948-1993). Lifetime history of DSM-III-R psychotic disorder and psychotic symptom dimensions was assessed from clinical records and research interviews and rated using the Operational Criteria Checklist. Estimates of heritability and environmental components of variance in liability were made with structural equation modeling using a causal-contingent common pathway model adapted for ascertainment from a clinical register. Significant heritability was found for DSM-III-R psychotic disorder (h² = 90%, 95%CI 68-94%) and the disorganized symptom dimension (h² = 84%, 95%CI 18-93%). The heritability for the disorganized dimension remained significant when influences acting through liability to psychosis were set to zero, suggesting that some influences on disorganization are modifying factors independent of psychosis liability. However, the relative extent of modifying factors versus influences acting through psychosis liability could not be clearly determined. To our knowledge, this study provides the first formal evidence of substantive heritability for the disorganized symptom dimension, and suggests that genetic loci influencing disorganization in individuals with psychoses are in some cases different from loci that influence risk of psychotic disorders themselves.

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“…[21,25], factor analysis, e.g. [11,13], latent class analysis [1,31], or grade-of-membership models [19,26]. The method [14] that is presented in this study does not attempt a priori to identify clusters, categories or dimensions, but rather depicts the relations between objects in a Euclidean space in a structurally neutral way.…”

Section: Introductionmentioning

confidence: 99%

Combining the categorical and the dimensional perspective in a diagnostic map of psychotic disorders

Läge

Egli

Riedel

et al. 2010

Eur Arch Psychiatry Clin Neurosci

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We introduce a diagnostic map that was calculated by robust non-metric multidimensional scaling based on AMDP symptom profiles of patients with schizophrenic and affective disorders to demonstrate a possibility to combine the categorical and the dimensional perspective at the same time. In the diagnostic map, a manic, a depressive, and a non-affective cluster clearly emerged. At the same time, the mania dimension (r = 0.82), the depression dimension (r = 0.68), and the apathy dimension (r = 0.74) showed high multiple regression values in the map. We found substantial overlaps of the diagnostic groups with regard to the affective spectrum but irrespective of the ICD-10 classification. Within this sample, we found the association and quality of mood symptoms to be a structuring principle in a diagnostic map. We demonstrate that this approach represents a promising way of combining the categorical and the dimensional perspective. As a practical implementation of these findings, a multidimensional diagnostic map could serve as an automated diagnostic tool based on psychopathological symptom profiles.

show abstract

Dimensions and classes of psychosis in a population cohort: a four-class, four-dimension model of schizophrenia and affective psychoses

Cited by 69 publications

References 60 publications

Kraepelin Was Right: A Latent Class Analysis of Symptom Dimensions in Patients and Controls

Kraepelin Was Right: A Latent Class Analysis of Symptom Dimensions in Patients and Controls

Heritability estimates for psychotic symptom dimensions in twins with psychotic disorders

Combining the categorical and the dimensional perspective in a diagnostic map of psychotic disorders

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