[Accelerated increase in the number of involuntary admissions following the implementation of the Dutch Act on Compulsory Admission to Psychiatric Hospitals (BOPZ)].

OBJECTIVE: To determine whether the observed accelerated increase in the number of involuntary admissions in The Netherlands coincides with the implementation of the Dutch Act on Compulsory Admission to Psychiatric Hospitals (BOPZ) in 1994.
DESIGN: Retrospective.
METHOD: The extent to which the number of involuntary admissions changed after implementation of the BOPZ was examined by means of Poisson regression on the basis of national data from the Patient Registration of Intramural Mental Healthcare for the period 1979-1995 and data from the Healthcare Inspectorate for the period 1992-2004. For this purpose, the curve prior to implementation of the BOPZ was compared with that following its implementation.
RESULTS: The number of involuntary admissions of psychiatric patients had more than doubled in 25 years, from 3101 in 1979 to 7450 in 2004. The increase in annual numbers accelerated significantly after implementation of the BOPZ in 1994.
CONCLUSION: There was an accelerated increase in the number of involuntary admissions after the implementation of the BOPZ. Other possible contributing factors include an increased number of admissions, shorter hospital stays, and changes in social concepts.