Admissions to mental hospitals can be either voluntary or involuntary. Involuntary admissions in this article are admissions in virtue of a committal to custody or a judicial authorization. Admissions in pursuance of the administration of penal law are not dealt with in this article. In a comparative study of involuntary admissions related to inhabitants of the cities of Amsterdam, Rotterdam, The Hague, the province of Friesland compared with the national average, on the period 1979-1983 remarkable differences between these areas have emerged.

It is unlikely that only demographic features of the investigated areas or the incidence of acute mental disorders there, required an involuntary admission, can be made responsible for the differences. It is assumed that the differences in policy of the legal and mental health autorities as to involuntary admissions in the various areas also play an important explanatory role.

A qualitative research would be needed to achieve a greater understanding of the quantitative results and differences as to involuntary admissions found particularly in de cities of Rotterdam and The Hague. In view of this the attitude and practice of mental health organisations, the judiciary and the police would have to be thoroughly investigated in a further comparative study.