Since 1999 the Portuguese law envisages compulsory admission as a Court decision based on major psychiatric criteria: dangerousness and need for treatment. The rate of compulsory versus total admissions in Portugal has increased since then, maintaining, however, one of the lowest reported rate in Europe. This trend is also noted in other European countries and there is a current debate concerning the underlying reasons.

To examine whether the decision criteria for compulsory admissions has changed over time in a general hospital in Lisbon.

We conducted a retrospective study in two non-probabilistic samples of compulsorily admitted patients with no prior involuntarily admissions in a general hospital in Lisbon: the first one hundred patients admitted in 1999 and the last one hundred admitted in 2009 were selected. Data was collected from patient files using a standardized questionnaire.

There were no significant differences between samples concerning age, gender, employment, living alone, duration of illness, duration of hospital stay, drugs use or mandatory outpatient treatment. The diagnostic of affective disorders, the overt violent behaviour and depot medication at hospital discharge increased significantly (p < 0.05) in the 2009 sample.

There seems to be no changing in the decision criteria of compulsory admission envolving sociodemographic variables. The increasing rate of compulsory admissions may be due to the increasing admission of patients presenting affective disorders and overt aggressive behaviour, and hence, this may be caused by the application of criteria of dangerousness and of need for treatment.