Mental examination patients are admitted to the Hospital at the order of a court. The National Supervisory Authority for Welfare and Health (Valvira) determines the institution where mental examination of the accused will be carried out. The Mental Health Act states that the examination may last a maximum of 2 months. At Niuvanniemi Hospital the average duration of mental examinations is 53 days. On the basis of the Mental Health Act a person undergoing mental examination may be kept at the hospital against his or her will.
In 2019 Niuvanniemi carried out a total of 52 mental examinations, with approximately seven mental examination patients at the hospital at any one time.