Association between cannabis use and psychosis-related outcomes using sibling pair analysis in a cohort of young adults.

Context: Prospective cohort studies have identified an association between cannabis use and later psychosis-related outcomes, but concerns remain about unmeasured confounding variables. The use of sibling pair analysis reduces the influence of unmeasured residual confounding.

Objective: To explore the association between cannabis use and psychosis-related outcomes.

Psychotic-like experiences in major depression and anxiety disorders: a population-based survey in young adults.

Objective: Population-based surveys have confirmed that psychotic-like experiences are prevalent in the community. However, it is unclear if these experiences are associated with common mental disorders. The aim of this study was to examine the prevalence of psychotic-like experiences in those with affective and anxiety disorders.

Psychopathology during childhood and adolescence predicts delusional-like experiences in adults: a 21-year birth cohort study.

Objective: Community surveys have shown that many otherwise well individuals report delusional-like experiences. The authors examined psychopathology during childhood and adolescence as a predictor of delusional-like experiences in young adulthood.

Method: The authors analyzed prospective data from the Mater-University of Queensland Study of Pregnancy, a birth cohort of 3,617 young adults born between 1981 and 1983.

Growth in young adults who screen positive for non-affective psychosis: birth cohort study.

Objective: While birth cohort studies have shown that individuals who develop non-affective psychosis show subtle deviations in cognitive and behavioural developmental trajectories, there is less evidence about deviations in physical growth in these individuals. The purpose of the present study was to examine the association between behaviour and growth and maturation from infancy, through childhood and adolescence to early adulthood and the development of non-affective psychosis in young adults.

Method: Based on a birth cohort of 3801 young adults, weight and length/height were examined at birth and at years 5, 14 and 21, together with pubertal maturation at year 14.

The antecedents of schizophrenia: a review of birth cohort studies.

Background: Birth cohort (BC) studies demonstrate that individuals who develop schizophrenia differ from the general population on a range of developmental indices. The aims of this article were to summarize key findings from BC studies in order to identify areas of convergence and to outline areas requiring further research.

Method: We define BC studies as studies based on general population BCs where data are collected prospectively from birth or childhood and which identify schizophrenia or related disorders as an outcome.

Schizophrenia: a concise overview of incidence, prevalence, and mortality.

Recent systematic reviews have encouraged the psychiatric research community to reevaluate the contours of schizophrenia epidemiology. This paper provides a concise overview of three related systematic reviews on the incidence, prevalence, and mortality associated with schizophrenia. The reviews shared key methodological features regarding search strategies, analysis of the distribution of the frequency estimates, and exploration of the influence of key variables (sex, migrant status, urbanicity, secular trend, economic status, and latitude).

Clinical and demographic features of treated first-episode psychotic disorders: a Zambian study.

Background: There is a relative lack of information about the epidemiology of psychotic disorders in the developing world. The aim of this pragmatic study was to describe the correlates of first-episode psychosis in the central African nation of Zambia.

Method: Selected clinical and demographic variables were collected on patients with psychotic disorders presenting for the first time at the only psychiatric hospital in Zambia (Chainama Hills College Hospital, Lusaka).

Incidence of schizophrenia does not vary with economic status of the country: evidence from a systematic review.

Background: A recent systematic review found that the prevalence of schizophrenia was lower in developing nations compared to developed nations. However, there is a lack of information about the association between economic status and the incidence of schizophrenia. The aim of this study was to examine the association between economic status and the underlying incidence of schizophrenia based on a recently published systematic review of the incidence of schizophrenia.

Age-at-first-registration for affective psychosis and schizophrenia.

We compared the age-at-first-registration for patients with schizophrenia and affective psychosis in a statewide mental health register. After excluding those receiving (1) a diagnosis of both schizophrenia (ICD-9 295.x) and affective psychosis (ICD-9 296.

A systematic review of the prevalence of schizophrenia.

Background: Understanding the prevalence of schizophrenia has important implications for both health service planning and risk factor epidemiology. The aims of this review are to systematically identify and collate studies describing the prevalence of schizophrenia, to summarize the findings of these studies, and to explore selected factors that may influence prevalence estimates.

Methods And Findings: Studies with original data related to the prevalence of schizophrenia (published 1965-2002) were identified via searching electronic databases, reviewing citations, and writing to authors.

A systematic review of the incidence of schizophrenia: the distribution of rates and the influence of sex, urbanicity, migrant status and methodology.

Background: Understanding variations in the incidence of schizophrenia is a crucial step in unravelling the aetiology of this group of disorders. The aims of this review are to systematically identify studies related to the incidence of schizophrenia, to describe the key features of these studies, and to explore the distribution of rates derived from these studies.

Methods: Studies with original data related to the incidence of schizophrenia (published 1965-2001) were identified via searching electronic databases, reviewing citations and writing to authors.

Paternal and maternal age as risk factors for psychosis: findings from Denmark, Sweden and Australia.

Background: While the association between increased maternal age and congenital disorders has long been recognized, the offspring of older fathers are also at increased risk of congenital disorders related to DNA errors during spermatogenesis. Recent studies have drawn attention to an association between increased paternal age and increased risk of schizophrenia. The aim of the current study was to examine both paternal and maternal age as risk factors for the broader category of psychosis.

A systematic review and meta-analysis of Northern Hemisphere season of birth studies in schizophrenia.

Based on the epidemiological finding that individuals with schizophrenia tend to be born in winter/spring when compared to the general population, we examined (1) the strength and timing of this effect in Northern Hemisphere sites, and (2) the correlation between the season of birth effect size and latitude. Studies were located via electronic data sources, published citations, and letters to authors. Inclusion criteria were that studies specify the diagnostic criteria used, that studies specify the counts of schizophrenia and general population births for each month, and that subjects and the general population be drawn from the same birth years and catchment area.

Directional and fluctuating asymmetry in finger and a-b ridge counts in psychosis: a case-control study.

Background: Several studies have reported alterations in finger and a-b ridge counts, and their derived measures of asymmetry, in schizophrenia compared to controls. Because ridges are fully formed by the end of the second trimester, they may provide clues to disturbed early development. The aim of this study was to assess these measures in a sample of patients with psychosis and normal controls.

Age-at-first-registration and heterogeneity in affective psychoses.

Background: Previous research into age of onset in affective disorders has produced conflicting results. This paper examines the influence of heterogeneity on the age-at-first-registration distribution for the ICD-9 diagnostic group 'affective psychosis'.

Method: For 1979-1991, data for age-at-first-registration for 4985 individuals diagnosed with affective psychosis (ICD-9 296.

No significant association between prenatal exposure poliovirus epidemics and psychosis.

Objective: To examine the association between prenatal exposure to poliovirus infection and later development of schizophrenia or affective psychosis in a Southern Hemisphere psychiatric register.

Methods: We calculated rates of poliomyelitis cases per 10 000 background population and rates for schizophrenia(n = 6078) and affective psychosis (n = 3707)per 10 000 births for the period 1930-1964. Empirically weighted regression was used to measure the association between a given psychosis birth-rate and a poliomyelitis epidemic during gestation.