Seclusion and mechanical restraint are widely used for people with serious mental disorders. In most countries one intervention is preferred while the other is considered as inhuman or not sufficiently safe, but identical arguments refer to different preferences. There is a lack of evidence from well-designed studies on compulsory measures in psychiatry.

We conducted a cohort study with optional randomisation comparing seclusion and mechanical restraint among in-patients with acute psychotic disorders. We determined an ethical aspect as main outcome variable: the restriction of human rights from the patients' point of view, measured by a scale developed for this purpose, Human DIgnity during COercive Procedures, DICOP-Score.

102 out of 233 patients exposed to coercive measures within 24 months could be included, 26 could be randomised (12 seclusion, 14 restraint). There were no significant differences between the two interventions referring to DICOP-score and duration of the intervention. The burdens most frequently reported were solitude, loss of dignity, and not having understood why the intervention was done. Watching pictures of several alternatives in the interview, including physical restraint and net bed (not available in Germany), most patients preferred seclusion.

Both from ethical and safety aspects the results do not yield evidence to prefer or forbid one of the interventions. Clinical decisions should take into account patients' preferences.