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.

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.

Minor physical anomalies and quantitative measures of the head and face in patients with psychosis.

Background: The aim of this study was to examine minor physical anomalies and quantitative measures of the head and face in patients with psychosis vs healthy controls.

Methods: Based on a comprehensive prevalence study of psychosis, we recruited 310 individuals with psychosis and 303 controls. From this sample, we matched 180 case-control pairs for age and sex.