A new Cambridge-led study has examined the past 60 years of incidence data on psychotic disorders in England in the hope that the data can reveal clues about the possible social factors which appear to underpin such conditions.
The systematic review published in PLoS One, which was conducted by the Department of Psychiatry EpiCentre at the University of Cambridge in collaboration with the Institute of Psychiatry, KCL, examined incidence rates of schizophrenia and other psychotic disorders in England between 1950-2009.
Dr. James Kirkbride, Sir Henry Wellcome Postdoctoral Research Fellow at the University of Cambridge, explains: Our review confirms that the social environment is an important determinant of risk for psychotic disorders; genetic factors are not the sole causes and, where important, must often operate in conjunction with the environment.
By analyzing the results of all relevant studies available since 1950, the research team showed that urban settings tended to experience higher rates of some psychotic disorders, such as schizophrenia. The study also confirmed that rates of psychotic disorder were elevated in several migrant groups and their offspring in England.
The findings mark an important step in being able to anticipate how the risk of psychotic disorders varies according to sociodemographic factors and characteristics of the social environment, so that appropriate healthcare can be provided. It shows that both the brain and its environment are crucial elements in understanding serious mental illnesses such as schizophrenia.
The results also have important implications for public health and planning services in the NHS. Dr. Kirkbride said These data will allow us to build prediction models for the expected number of new cases of psychotic illness in different regions of England, according to the exact sociodemographic composition of their populations, and according to other social factors such as economic deprivation or social cohesion.
The study found no evidence to support an overall change or increase of psychotic disorder over time, though the study did chart a diagnostic shift away from schizophrenia.
The study Incidence of schizophrenia and other psychoses in England, 1950-2009: a systematic review and meta-analyses was funded by the Department of Health Policy Research Programme, the NIHR and the Wellcome Trust. 83 citations from previous studies spanning the 60 years qualified for inclusion into the analysis.