Background Despite the tendency for harmonisation of strategies formental health care delivery, rules andregulations for involuntaryplacementor treatmentof mentally ill persons still differ remarkably internationally.Rapid European integration and other political developments require valid andreliab

Declaration of interest None. Fundingdetailed in Acknowledgements. Rates of involuntary placement or treatment of people with mental illness are widely considered to be an indicator for underlying characteristics of national mental health care laws or other legal frameworks. Unfortunately, despite the growing international mental health law debate, sound data on the international practice of compulsory admission are scarce (Riecher-Rossler & ̈ Rossler, 1993). Most of the few published ̈ international comparisons in this area include only selected nations (Laffont & Priest, 1992; Legemaate, 1995; van Lysbetten & Igodt, 2000). Findings suffer from reduced availability and reliability of data. Varying definitions or methods adopted by national health departments or statistical bureaus contribute to sometimes dramatic differences in compulsory admission rates or quotas (Riecher-Rossler & ̈ Rossler, 1993). Time series are especially ̈ scarce. When available, strong changes over time seem to indicate that rates or quotas are subject to a broad set of influencing factors, including changing legal frameworks, varying administrative routines and differences in quality standards of national or regional mental health care systems (Miller & Fiddleman, 1983; Engberg, 1991; Kokkonen, 1993; Lecompte, 1995; Kjellin, 1997; Wall et al, 1999; de Girolamo & Cozza, 2000). In the search for predictive factors for compulsory admission rates, some sociodemographic characteristics have been identified as increasing the risk of being placed involuntarily (Gove & Fain, 1977; Mahler & Co, 1984; Dunn & Fahy, 1990; Davies et al, 1996; Sanguineti et al, 1996; Singh et al, 1998; Crisanti & Love, 2001), although some of the findings are contradictory (Szmulker et al, 1981; Nicholson, 1988; Tremblay et al, 1994). All in all, the scarcity of data and the variety of controversial research results may be attributed to a complex set of poorly understood legal, political, economical, social, medical, methodological and other factors interacting in the process. Rapid European integration requires valid overviews and a sound database for increased research concerning this most controversial and important issue.