The study was based on data from the Danish Psychiatric Central Register. It consisted of 11,753 persons with permanent residence in the municipalities of Aalborg or Arhus, who had 32,557 admissions to a psychiatric hospital in Denmark during the period 1982-1991. The admission rates declined by 30%. The involuntary admission rate increased during the later years of the period, it was higher at the Psychiatric Hospital in Arhus (PHA). The bedday use per admission was 5.5 weeks on average at Aalborg Psychiatric Hospital (AAPH) and nine weeks on average at PHA. Through the period the bed rate (beds in use) was gradually reduced by 40%, most significantly at PHA. It can be concluded that the treatment at AAPH was less time-consuming. This is mainly caused by there being fewer beds available. Indices for quality of outcome did not give reason for conclusions in regard to differences in quality of treatment.