Department of Economics and Business Economics

A register based epidemiological description of risk factors and outcomes for major psychiatric disorders, focusing on a comparison between bipolar affective disorder and schizophrenia.

Research output: Book/anthology/dissertation/reportPh.D. thesisResearch


  • National Centre for Register-based Research

This Ph.D. thesis summarizes the results from 3 cohort studies describing risk factors for and mortality of major psychiatric disorders with focus on comparison between schizophrenia and bipolar affective disorder. Furthermore, the results are evaluated in the context of the dichotomization of schizophrenia and bipolar affective disorder.

The studies were based on four Danish registers: the Psychiatric Central Register, the Danish Civil Registration System, the Cause of Death Register, and the Danish Medical Birth Register. From the registers, large population based cohorts were identified and followed over several decades. Survival analysis techniques were applied to identify risk factors and mortality rates.

The results demonstrated an overlap in risk factors for schizophrenia and bipolar affective disorder. Excess mortality (compared to persons never admitted with a psychiatric disorder) was present in persons suffering from the two disorders. Differences were also found between the phenotypes, but they were quantitative rather than qualitative, that is, only magnitude, and not direction of the risk factors (and the excess mortality), differed. Results were not conflicting when they were held up against other models than the traditional Kraepelinian dichotomization of the disorders.

In conclusion, the results suggest that schizophrenia and bipolar affective disorder patients have a genetic vulnerability or predisposition towards the disorders (possibly at least overlapping), and environmental factors act (or interact) with this predisposition. However, large differences in gender distribution and age at onset are present, and differences and similarities between the disorders should be further examined before the Kraepelinian dichotomization can be disregarded.

Original languageEnglish
Place of publicationUniversity of Aarhus
Publication statusPublished - 2006

    Research areas

  • Schizophrenia, Bipolar disorder, Schizoaffective disorder, Epidemiology

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