Objective: Much of the knowledge we now take for granted regarding major mental disorders such as schizophrenia, suicide and other disorders, would not exist without the use of population based registers. The use of population based registers in psychiatric epidemiology have enabled analyses of associations that otherwise would not have been possible to address.
Method: The use of registers in psychiatric research is described, exemplified, and discussed.
Results: Methodological and validity aspects depend to a large part on the type of register being considered. A classification is proposed of different types of registers, each one implying specific methodological issues. These can be addressed according to the dimensions coverage, attrition, representativity and validity. Specific methodological consideration has still to be taken in relation to each specific research question. Thus, special validity studies usually need to be performed when embarking on studies using population based registers.
Conclusion: With increasing burden of disease due to mental disorders worldwide, knowledge of the epidemiology of these disorders are of increasing interest. The Nordic countries have a strong history in this field of research, of great interest to the rest of the world. Universities and research funding agencies should recognize this valuable source of research capacity, and support fruitful continuation of a strong tradition.