Does urbanicity shift the population expression of psychosis?

Department of Psychiatry and Neuropsychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University, P.O. Box 616 (DRT 10), 6200 MD Maastricht, The Netherlands.
Journal of Psychiatric Research (Impact Factor: 4.09). 11/2004; 38(6):613-8. DOI: 10.1016/j.jpsychires.2004.04.003
Source: PubMed

ABSTRACT Growing up in an urban area has been shown to be associated with an increased risk of psychotic disorder in later life. While it is commonly held that a only a tiny fraction of exposed individuals will develop schizophrenia, recent evidence suggests that expression of psychosis in exposed individuals may be much more common, albeit at attenuated levels. Findings are based on a population sample of 2548 adolescents and young adults aged originally 14-24 years, and followed up over almost 5 years up to ages 17-28 years. Trained psychologists assessed all these subjects with the core psychosis sections on delusions and hallucinations of the Munich-Composite International Diagnostic Interview. Growing up in an urban area was associated with an increased risk of expression of psychosis in the adolescents and young adults (adjusted OR 1.31, 95% CI 1.03-1.66). The proxy environmental risk factor that urbanicity represents may shift a relatively large section of the adolescent population along a continuum of expression of psychosis. Other causal influences may be required to make the transition to schizophrenia in adult life.

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    • "An important observation is that studies have demonstrated that the generally good (because the symptoms are only transitory as described above) outcome of subclinical psychotic experiences can be modified to poorer outcomes of persistence and clinical need for care if subjects are exposed to additional (proxy) environmental risk factors. Examples of these are trauma (Spauwen et al. 2006b), cannabis (Henquet et al. 2005) and urbanicity (Spauwen et al. 2004, 2006a). This fact, together with the above discussed findings of a high prevalence of psychotic experiences, their familial clustering, age-associated expression and low rate of transition to psychotic disorder, suggests a model of psychosis that considers genetic background factors impacting on a broadly distributed and transitory population expression of psychosis during development, the poor prognosis of which, in terms of persistence and clinical need, is predicted by environmental exposures interacting with genetic risk. "
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    ABSTRACT: A systematic review of all reported incidence and prevalence studies of population rates of subclinical psychotic experiences reveals a median prevalence rate of around 5% and a median incidence rate of around 3%. A meta-analysis of risk factors reveals associations with developmental stage, child and adult social adversity, psychoactive drug use, and also male sex and migrant status. The small difference between prevalence and incidence rates, together with data from follow-up studies, indicates that approximately 75-90% of developmental psychotic experiences are transitory and disappear over time. There is evidence, however, that transitory developmental expression of psychosis (psychosis proneness) may become abnormally persistent (persistence) and subsequently clinically relevant (impairment), depending on the degree of environmental risk the person is additionally exposed to. The psychosis proneness-persistence-impairment model considers genetic background factors impacting on a broadly distributed and transitory population expression of psychosis during development, poor prognosis of which, in terms of persistence and clinical need, is predicted by environmental exposure interacting with genetic risk.
    Psychological Medicine 08/2008; 39(2):179-95. DOI:10.1017/S0033291708003814
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    • "Their effects are small and many may be involved. They are likely to interact with environmental exposures that impact on the individual over the life course, such as fetal hypoxia (Cannon et al., 2002), the proxy environmental risk factor: season of birth (Mortensen et al., 1999), adverse rearing environments (Tienari et al., 2004), the stresses of urban life during upbringing (van Os et al., 2003, Spauwen et al., 2004), cannabis use (Verdoux et al., 2003), stress in daily life (Myin-Germeys et al., 2001) and a minority position (Hutchinson et al., 1996). The causes of schizophrenia impact on brain development, as evidenced by a small reduction in the volume of grey matter (Wright et al., 2000) that appears to progress over time, and may be linked to social deterioration, use of medication or factors intrinsic to the disease itself (Cahn et al., 2002, Ho et al., 2003a,b). "
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    ABSTRACT: Schizophrenia is a severe mental disorder characterised by fundamental disturbances in thinking, perception and emotions. More than 100 years of research have not been able to fully resolve the puzzle that schizophrenia represents. Even if schizophrenia is not a very frequent disease, it is among the most burdensome and costly illnesses worldwide. It usually starts in young adulthood. Life expectancy is reduced by approximately 10 years, mostly as a consequence of suicide. Even if the course of the illness today is considered more favourable than it was originally described, it is still only a minority of those affected, who fully recover. The cumulative lifetime risk for men and women is similar, although it is higher for men in the age group younger than 40 years. According to the Global Burden of Disease Study, schizophrenia causes a high degree of disability, which accounts for 1.1% of the total DALYs (disability-adjusted life years) and 2.8% of YLDs (years lived with disability). In the World Health Report [The WHO World Health Report: new understanding, new hope, 2001. Geneva], schizophrenia is listed as the 8th leading cause of DALYs worldwide in the age group 15-44 years. In addition to the direct burden, there is considerable burden on the relatives who care for the sufferers. The treatment goals for the moment are to identify the illness as early as possible, treat the symptoms, provide skills to patients and their families, maintain the improvement over a period of time, prevent relapses and reintegrate the ill persons into the community so that they can lead as normal a life as possible.
    European Neuropsychopharmacology 09/2005; 15(4):399-409. DOI:10.1016/j.euroneuro.2005.04.009
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    • "The review carried out regarding psychotic experiences in adolescence (see Table 1) seems to point out that the distribution and proportion of these can vary considerably as a function of the measurement instrument employed. R e g u l a r a r t i c l e 66 ATTENUATED PSYCHOTIC EXPERIENCES IN ADOLESCENTS TABLE 1 PREVALENCE STUDIES OF ATTENUATED PSYCHOTIC EXPERIENCES IN ADOLESCENTS Study (Pearson et al., 2008) (Scott et al., 2008) (Scott et al., 2008) (De Loore et al., 2008) (Horwood et al., 2008) (Laurens et al., 2007) (Spauwen et al., 2006a) (Spauwen et al., 2006b) (Yung et al., 2006) (Henquet et al., 2005) (Yoshizumi et al., 2004) (Spauwen et al., 2004) (Ferdinand et al., 2004) (Spauwen et al., 2003) "
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    ABSTRACT: The so-called subclinical or attenuated psychotic experiences are psychotic signs and symptoms which do not manifest themselves at a clinical level. It therefore consists of a group of symptoms similar to those of schizophrenia which can be present in the general population and distributed along a continuum of severity, at whose extreme end we find psychosis. The objective of the present study was to perform an exhaustive review of the literature related to the prevalence rates of psychotic experiences in nonclinical adolescent populations published in recent years. In addition, the frequency of these psychotic experiences in Spanish adolescents was examined. The results show that psychotic experiences are common and transitory phenomena in adolescence which are not necessarily associated with the presence of psychopathology or later risk for psychosis. Moreover, the data suggest that the psychotic phenotype goes beyond the frontiers proposed by the international classification systems. Future lines of research should examine and gain a deeper understanding of these types of experiences
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