Many North American jurisdictions permit involuntary psychiatric treatment to proceed only when a person lacks the capacity (or competence) to consent or when an emergency exists, even following lawful civil commitment. This may prevent the rapid commencement of treatment, but it shows considerable respect for personal autonomy, and it brings mental health law more into line with other branches of health care law. The authors examine how these issues are handled within European human rights law and within the civil codes and involuntary hospitalization laws of selected European nations. This material reveals that many different approaches are taken to the inclusion of incapacity principles within European civil commitment regimes. Reliance on incapacity criteria may lead to greater professional involvement by psychologists in involuntary treatment decisions.