University of Oulu

Filatova, S.; Marttila, R.; Koivumaa-Honkanen, H.; Nordström, T.; Veijola, J.; Mäki, P.; Khandaker, G. M.; Isohanni, M.; Jääskeläinen, E.; Moilanen, K.; Miettunen, J. A comparison of the cumulative incidence and early risk factors for psychotic disorder in young adults in the Northern Finland Birth Cohorts 1966 and 1986. Epidemiology and Psychiatric Sciences, Volume 26, Issue 3, June 2017, pp. 314-324. DOI: 10.1017/S2045796016000123

A comparison of the cumulative incidence and early risk factors for psychotic disorder in young adults in the Northern Finland Birth Cohorts 1966 and 1986

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Author: Filatova, S.1,2; Marttila, R.1,2; Koivumaa-Honkanen, H.3,4,5,6,7,8,9;
Organizations: 1Center for Life Course Health Research, University of Oulu, Oulu, Finland
2Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland
3Institute of Clinical Medicine (Psychiatry), University of Eastern Finland, Kuopio, Finland
4Departments of Psychiatry, Kuopio University Hospital, Kuopio
5Departments of Psychiatry, South-Savonia Hospital District, Mikkeli
6Departments of Psychiatry, North Karelia Central Hospital, Joensuu
7Departments of Psychiatry, SOSTERI, Savonlinna
8Departments of Psychiatry, SOTE, Iisalmi
9Departments of Psychiatry, Lapland Hospital District, Rovaniemi, Finland
10Department of Psychiatry, Center of Clinical Neuroscience, University of Oulu, Oulu, Finland
11Department of Psychiatry, Oulu University Hospital, Oulu, Finland
12Department of Psychiatry, The Middle Ostrobothnia Central Hospital, Kiuru, Finland
13Department of Psychiatry, Mental Health Services, Joint Municipal Authority of Wellbeing in Raahe District, Finland
14Department of Psychiatry, Mental Health Services, Basic Health Care District of Kallio, Finland
15Department of Psychiatry, Visala Hospital, Ylivieska, the Northern Ostrobothnia Hospital District, Finland
16Department of Psychiatry, Länsi-Pohja Healthcare District, Finland
17Department of Psychiatry, University of Cambridge, Cambridge, UK
18Cambridgeshire and Peterborough NHS Foundation Trust, Cambridge, UK
19Unit of Primary Health Care, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.2 MB)
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Language: English
Published: Cambridge University Press, 2017
Publish Date: 2017-06-06


Aims: Few studies have compared time trends for the incidence of psychosis. To date, the results have been inconsistent, showing a decline, an increase or no significant change. As far as we know, no studies explored changes in prevalence of early risk factors. The aim of this study was to investigate differences in early risk factors and cumulative incidences of psychosis by type of psychosis in two comparable birth cohorts.

Methods: The Northern Finland Birth cohorts (NFBCs) 1966 (𝑁 = 12 058) and 1986 (𝑁 = 9432) are prospective general population-based cohorts with the children followed since mother’s mid-pregnancy. The data for psychoses, i.e. schizophrenia (narrow, spectrum), bipolar disorder with psychotic features, major depressive episode with psychotic features, brief psychosis and other psychoses (ICD 8–10) were collected from nationwide registers including both inpatients and outpatients. The data on early risk factors including sex and place of birth of the offspring, parental age and psychosis, maternal education at birth were prospectively collected from the population registers. The follow-up reached until the age of 27 years.

Results: An increase in the cumulative incidence of all psychoses was seen (1.01% in NFBC 1966 v. 1.90% in NFBC 1986; p < 0.001), which was due to an increase in diagnosed affective and other psychoses. Earlier onset of cases and relatively more psychoses in women were observed in the NFBC 1986. Changes in prevalence of potential early risk factors were identified, but only parental psychosis was a significant predictor in both cohorts (hazard ratios ≥ 3.0; 95% CI 1.86–4.88). The difference in psychosis incidence was not dependent on changes in prevalence of studied early risk factors.

Conclusions: Surprisingly, increase in the cumulative incidence of psychosis and also changes in the types of psychoses were found between two birth cohorts 20 years apart. The observed differences could be due to real changes in incidence or they can be attributable to changes in diagnostic practices, or to early psychosis detection and treatment.

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Series: Epidemiology and psychiatric sciences
ISSN: 2045-7960
ISSN-E: 2045-7979
ISSN-L: 2045-7960
Volume: 26
Pages: 314 - 324
DOI: 10.1017/S2045796016000123
Type of Publication: A1 Journal article – refereed
Field of Science: 3124 Neurology and psychiatry
Funding: The research leading to these results has receivedfunding from the People Programme (Marie CurieActions) of the European Union’s Seventh Framework Programme FP7/ 2007–2013 under REA grant agreement no 316795 and the Academy of Finland (#132071, #268336, #278286), the Brain and Behavior Research Foundation, the Jalmari and Rauha Ahokas Foundation, the Sigrid Jusélius Foundation, and the Northern Finland Health Care Support Foundation, and the Signe and Ane Gyllenberg Foundation, Finland.
Academy of Finland Grant Number: 132071
Detailed Information: 132071 (Academy of Finland Funding decision)
268336 (Academy of Finland Funding decision)
278286 (Academy of Finland Funding decision)
Copyright information: © Cambridge University Press 2016. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.