The use of coercion raises ethical dilemmas, as it deprives patients of their autonomy. In Denmark, the subject has gained political attention, and decreases in the use of coercion are demanded. In the attempt of reducing the use of coercion, it is of interest to obtain more knowledge about the circumstances bound to it.

The aim of this study was to investigate a possible correlation between the incidence of mechanical restraint (MR), and staffing level, staff demographics, patient characteristics, type of shift (day/evening/night) and change of shifts.

A naturalistic descriptive method was used to study cases of mechanical restraint in patients admitted to a psychiatric ward. In the study period of one year, 114 cases of MR were carried out. In 66% of cases, the patient was diagnosed with borderline personality disorder. Each case of MR was obtained from Statens Serum Institut's Electronic Reporting System. The care workers from each shift were identified using duty rosters. The statistical package SPSS version 20 was used for data processing, including a logistic regression analysis.

A significant association was found between the use of MR and the presence of male care workers on the ward, OR = 1.639, 95% CI: 1.163–2.311, P = 0.005. The risk of MR is increased during evening shifts, compared to day and night shifts, OR = 1.868, 95% CI: 1.165–2.995, P = 0.009. No significant associations were found between MR and staffing level, age, education, or experience of care workers.

The authors have not supplied their declaration of competing interest.