BACKGROUND: Several studies have reported a decline of up to 50% in the incidence of schizophrenia over recent decades. We aimed to measure changes in the incidence and diagnostic patterns of first-episode psychosis by comparing two Nottingham cohorts, identified in two equal periods separated by 14 years. METHOD: Two prospectively ascertained cohorts of first-episode psychotic disorder were identified over the time periods 1978-80 and 1992-94. The earlier cohort was of the World Health Organization Determinants of Outcome of Severe Mental Disorder (DOSMD) ten-country study. The later cohort was obtained using similar methodology. Both groups were diagnosed using ICD-10 diagnostic criteria and age-standardised incidence rates were compared. RESULTS: The standardised incidence rate for all psychotic disorders rose slightly from 2.49 to 2.87 per 10000 population per year, but the F20 classification fell significantly by over a third (1.41 to 0.87 per 10000 per year). The second study group (1992-1994) included a greater diversity of psychotic diagnoses compared with the first, in particular an increased proportion of acute and drug-related psychoses. CONCLUSIONS: Methodological considerations call for caution in interpreting such data, but we conclude that the significant fall in the narrowly defined diagnostic category of schizophrenia reflects a real change in the syndromal presentation of psychotic disorders.
BACKGROUND: Several studies have reported a decline of up to 50% in the incidence of schizophrenia over recent decades. We aimed to measure changes in the incidence and diagnostic patterns of first-episode psychosis by comparing two Nottingham cohorts, identified in two equal periods separated by 14 years. METHOD: Two prospectively ascertained cohorts of first-episode psychotic disorder were identified over the time periods 1978-80 and 1992-94. The earlier cohort was of the World Health Organization Determinants of Outcome of Severe Mental Disorder (DOSMD) ten-country study. The later cohort was obtained using similar methodology. Both groups were diagnosed using ICD-10 diagnostic criteria and age-standardised incidence rates were compared. RESULTS: The standardised incidence rate for all psychotic disorders rose slightly from 2.49 to 2.87 per 10000 population per year, but the F20 classification fell significantly by over a third (1.41 to 0.87 per 10000 per year). The second study group (1992-1994) included a greater diversity of psychotic diagnoses compared with the first, in particular an increased proportion of acute and drug-related psychoses. CONCLUSIONS: Methodological considerations call for caution in interpreting such data, but we conclude that the significant fall in the narrowly defined diagnostic category of schizophrenia reflects a real change in the syndromal presentation of psychotic disorders.
Authors: Richard Herrell; Ioline D Henter; Ramin Mojtabai; John J Bartko; Diane Venable; Ezra Susser; Kathleen R Merikangas; Richard J Wyatt Journal: Psychol Med Date: 2006-07-31 Impact factor: 7.723
Authors: Kim Donoghue; Ian Medley; John Brewin; Cristine Glazebrook; Peter Mason; Roch Cantwell; Peter B Jones; Glynn Harrison; Gillian A Doody Journal: Soc Psychiatry Psychiatr Epidemiol Date: 2009-12-31 Impact factor: 4.328
Authors: J B Kirkbride; T Croudace; J Brewin; K Donoghue; P Mason; C Glazebrook; I Medley; G Harrison; J E Cooper; G A Doody; P B Jones Journal: Int J Epidemiol Date: 2008-08-25 Impact factor: 7.196
Authors: James B Kirkbride; Antonia Errazuriz; Tim J Croudace; Craig Morgan; Daniel Jackson; Jane Boydell; Robin M Murray; Peter B Jones Journal: PLoS One Date: 2012-03-22 Impact factor: 3.240
Authors: David Healy; Joanna Le Noury; Stefanie Caroline Linden; Margaret Harris; Chris Whitaker; David Linden; Darren Baker; Anthony P Roberts Journal: BMJ Open Date: 2012-01-19 Impact factor: 2.692