A 15-year study has concluded that there is no benefit in locking up many mentally ill patients.
According to the study of 145,000 patients, published in The Lancet Psychiatry, an open-door policy does not increase the risk of suicide or of patients leaving without permission.
The study compared patients with the same severity of symptoms in four hospitals in Germany which had locked doors, and 16 which did not.
There was no difference in the rates of patients leaving without permission or hurting themselves, it found.
Oxford University psychiatry professor Tom Burns, whose commentary on the study was also published in The Lancet, told Nine To Noon an open-door policy could be preferable for those with depression, anxiety or psychosis, as it promoted a better therapeutic atmosphere and more positive health outcomes.
His work with Otago law professor John Dawson had also shown that patients being discharged with community treatment orders were just as likely to be re-admitted as those without, Mr Burns said.
Good psychiatry relied on staff engaging with patients, but locking hospital doors altered the atmosphere and experience for staff, patients and visitors.
Care had become over-formalised in a risk-averse system, Mr Burns said.
"Nurses now spend a third of their time filling out documents to prove they've done things, rather than sitting out in the ward with patients.
"The key to successful care - whether it's in the ward or out in the community - is how much time and energy and skill you bring to engaging with the patient."