In this article two Dutch studies into the relation between religion and psychiatric disorder are compared. In the first study the relation is explored between the church communion of the `Gereformeerde Gemeenten' and major depressive disorder resp. reactive psychosis. Aiming this communion the author speaks in his conclusion of `a risk factor for mental health'. The method of research used by the author, the case control study, has a lot of bottlenecks, which he leaves unsolved. In the other study the bottlenecks mentioned above are obviated. Here a relation is assessed between churchmembership and the (proportional) amount of requests for psychiatric hospitalisation. This relation does not immediately refer to the view of live in itself but to a sociological characteristic of the regarding religious group, the `sociocultural integration'.

The conclusion is that

_ for this purpose, a prevalence study is to be preferred above a case control study;

_ if a correlation is proved reliably, other characteristics (i.e. sociological or biological) can be responsable too.