Extended psychosis phenotype - Yes: Single continuum - Unlikely

Maastricht University Medical Centre, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht, The Netherlands.
Psychological Medicine (Impact Factor: 5.94). 03/2010; 40(12):1963-6. DOI: 10.1017/S0033291710000358
Source: PubMed
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    • "Evidence supports the presence of an extended pheno - type for psychosis existing across several dimensions , including an affective domain ( David , 2010 ; Kaymaz & van Os , 2010 ) . Further examination of the ex - tent to which specific characteristics distinguish PEs from other psychopathologies could lead to a greater understanding of the aetiology of psychosis . "
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    ABSTRACT: Background: An argument often used to support the view that psychotic experiences (PEs) in general population samples are a valid phenotype for studying the aetiology of schizophrenia is that risk factors for schizophrenia show similar patterns of association with PEs. However, PEs often co-occur with depression, and no study has explicitly tested whether risk factors for schizophrenia are shared between PEs and depression, or are psychopathology specific, while jointly modelling both outcomes. Method: We used data from 7030 subjects from a birth cohort study. Depression and PEs at age 18 years were assessed using self-report questionnaires and semi-structured interviews. We compared the extent to which risk factors for schizophrenia across sociodemographic, familial, neurodevelopmental, stress-adversity, emotional-behavioural and substance use domains showed different associations with PEs and depression within bivariate models that allowed for their correlation. Results: Most of the exposures examined were associated, to a similar degree, with an increased risk of both outcomes. However, whereas female sex and family history of depression showed some discrimination as potential risk factors for depression and PEs, with stronger associations in the former, markers of abnormal neurodevelopment showed stronger associations with PEs. Conclusions: The argument that PEs are valid markers for studying the aetiology of schizophrenia, made simply on the basis that they share risk factors in common, is not well supported. PEs seem to be a weak index of genetic and environmental risk for schizophrenia; however, studies disentangling aetiological pathways to PEs from those impacting upon co-morbid psychopathology might provide important insights into the aetiology of psychotic disorders.
    Psychological Medicine 09/2014; 44(12):2557-2566. DOI:10.1017/S0033291714000026 · 5.94 Impact Factor
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    • "There is emerging evidence that a latent categorical structure of the population underlies the observed continuum of psychosis experience,2 with 1 group who are liable to psychosis and another group who are not. In the former, AVH are associated with other cognitive and emotional difficulties and a greater likelihood of need for care, while in the second group, AVH have reduced morbidity and possibly different etiology.18 This could partly explain why 2 people with the same level of AVH may differ in their clinical outcome. "
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    ABSTRACT: Auditory verbal hallucinations (AVH) are complex experiences that occur in the context of various clinical disorders. AVH also occur in individuals from the general population who have no identifiable psychiatric or neurological diagnoses. This article reviews research on AVH in nonclinical individuals and provides a cross-disciplinary view of the clinical relevance of these experiences in defining the risk of mental illness and need for care. Prevalence rates of AVH vary according to measurement tool and indicate a continuum of experience in the general population. Cross-sectional comparisons of individuals with AVH with and without need for care reveal similarities in phenomenology and some underlying mechanisms but also highlight key differences in emotional valence of AVH, appraisals, and behavioral response. Longitudinal studies suggest that AVH are an antecedent of clinical disorders when combined with negative emotional states, specific cognitive difficulties and poor coping, plus family history of psychosis, and environmental exposures such as childhood adversity. However, their predictive value for specific psychiatric disorders is not entirely clear. The theoretical and clinical implications of the reviewed findings are discussed, together with directions for future research.
    Schizophrenia Bulletin 06/2014; 40(Suppl 4):S255-S264. DOI:10.1093/schbul/sbu005 · 8.45 Impact Factor
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    • "The sub-group of individuals reporting persistence or transition would represent those children and adolescents failing to compensate for the neurobiological and environmental adversity which was initially expressed as hallucinatory experiences, but also as higher general psychopathology levels and eventually need for care (Smeets et al., 2010). Persistence of hallucinatory experiences in a minority of the cases along the follow-up period, as opposed to the short term discontinuation in most of the cases would agree with two latent categories in psychotic experiences (Kaymaz and Van Os, 2010). Factor analysis techniques applied to the course of psychotic experiences may be useful to explore the latent structure of the extended phenotype of psychosis. "
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    ABSTRACT: Childhood and adolescence represent the periods during which hallucinatory experiences occur at the greatest prevalence, and also constitute a critical window of vulnerability for the pathogenesis of psychotic disorders. The longitudinal course of hallucinatory experiences during late childhood and adolescence, as well as their relationship to psychotic disorders, has never been the subject of review. We followed the PRISMA guidelines for conducting systematic reviews and combined the use of electronic and manual systematic search methods. Data were extracted upon pre-defined requested items and were analyzed using several epidemiological measures. The interpretation of the results was conducted in relation to the study design variables. A total of 11 datasets (6 epidemiological and 5 clinical) were reviewed. The baseline prevalence of hallucinatory experiences ranged from 4.9% to 9%. Discontinuation occurred in between 58.7% and 94.5% of the cases, and person-year discontinuation rates ranged from 3% to 40.7% and appeared to be related to the duration of follow-up. Despite low person-year incidence rate, incident cases constituted between 27.7% and 83.3% of outcome samples. 2 of 3 studies showed evidence to predict transition to psychosis with likelihood ratios of 2.5 and 6.6. Hallucinatory experiences are a common experience during childhood and adolescence. A review of the current literature suggests that there is a considerable turnover of incident-discontinuing cases and that most cases discontinue in the short term. A subset of the cases was at risk for persistence or transition to psychosis, probably related to indicators of severity of the hallucinatory experience.
    Schizophrenia Research 03/2012; 138(2-3):248-54. DOI:10.1016/j.schres.2012.03.012 · 3.92 Impact Factor
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