Register-based research of psychotic disorders in the Northern Finland Birth Cohorts

Background: The etiology of schizophrenia is still largely unknown. In studies of serious mental illnesses, such as schizophrenia, patients often participate poorly in field studies. In Finland, we have unique but often underutilised opportunities of studying register data, either on its own or in combination with other data.

Aims: The overall aim of the current study is to utilise register data on its own and in combination with interview and questionnaire data. The first specific aim of this study is to study the development and outcomes of psychotic illnesses by utilising national registers. We will explore clinical and social outcomes of schizophrenia and other psychotic illnesses by using national registers. The second aim is to evaluate strenghts and limitations of Hospital Discharge Register and registers of Social Insurance Institution in epidemiological research (etiology and prevalence) of psychotic disorders.

Methods of the study: In the prospective Northern Finland 1966 and 1986 Birth Cohorts, data has been collected since the pregnancy of the mother. Originally there were 12,058 children in the NFBC 1966 and 9,432 in the NFBC 1986 born in the two northernmost regions of Finland (Oulu and Lapland). We have register data concerning a number of relevant items, including hospital treatments, sick leaves, medications, disability pensions, unemployment, work periods, education and causes of death. The previously collected data, e.g. using questionnaires and interviews, will be linked to the register data.

Significance of the study: The NFBC studies are longitudinal population based studies with extensive interview and questionnaire data. The reliable Finnish registers offer a unique opportunity to combine this information to register data. Due to this, the studies utilising the cohort design and Finnish registers are likely to be of great interest for scientific community.

References (NFBC 1966)

Miettunen J, Lauronen E, Veijola J, Koponen H, Saarento O, Taanila A, Isohanni M. Socio-demographic and clinical predictors of occupational status in schizophrenic psychoses – follow-up within the Northern Finland 1966 Birth Cohort. Psychiatry Res 2007; 150:217-25.

Miettunen J, Lauronen E, Veijola J, Koponen H, Saarento O, Isohanni M. Patterns of psychiatric hospitalizations in schizophrenic psychoses within the Northern Finland 1966 Birth Cohort. Nord J Psychiatry 2006; 60:286-93.

We have also written a review on registers:

Miettunen J, Suvisaari J, Haukka J, Isohanni M. Use of Register Data for Psychiatric Epidemiology in the Nordic Countries. In: Textbook in Psychiatric Epidemiology, 3rd edition, Eds. Tsuang M, Tohen M, Jones P. Wiley-Blackwell. In press.