More than half of nurses on mental health wards have been physically attacked, a survey suggests.
Nurses reported the highest levels of attacks
Nurses working with older people are the most likely to be assaulted, the joint Healthcare Commission and Royal College of Psychiatrists report said.
The study of 69 NHS trusts and private hospitals in England and Wales said patients had also been attacked and more had to be done to stop violence.
Health bosses said the situation was taken "very seriously".
And it comes as the Health Service Journal reports that mental health staff are still waiting for violence training promised following the death of schizophrenia patient David Bennett in 1998.
He died after being restrained by staff at the Norvic Clinic in Norwich.
The audit covered eight in 10 of the organisations providing in-patient care for the 30,000 mental health patients in England and Wales.
Nurses, doctors, visitors and patients were all asked about whether they had suffered attacks, threats and what could be done about it.
Some 46% of nurses in mental health wards for working age patients said they had been assaulted.
For those working in older people's wards this rose to 64%.
Most of these attacks happened in those wards caring for people with "organic" conditions such as dementia rather than "functional" problems such as depression and schizophrenia.
Nurses reported they had suffered fractures, dislocations and black eyes.
Patients were also revealed to be under threat with a fifth of working age patients being attacked. For older patients, the figure dropped to 6%.
A fifth of clinical staff working with older people said they were attacked, with the figure dropping to 13% of those working with working age people.
The report said improvements were needed to reduce levels of violence, which many of those quizzed said was getting worse.
In particular, it suggested staffing levels should be increased, training improved and patients be given more activities.
However, it did acknowledge that in recent years attempts had been made by providing staff with alarms and improving the reporting of incidents.
Anna Walker, chief executive of the Healthcare Commission, said: "The audit reveals worrying levels of violence against staff in mental health units."
And Dr Peter Carter, general secretary of the Royal College of Nursing, added: "These levels of violence are deeply serious and unacceptable, whatever the area of care.
"The RCN commends nurses for maintaining the same dignified commitment to patient care, even under such constant threat."
Steve Shrubb, the director of the NHS Confederation's Mental Health Network, which represents managers, said the violence was "unacceptable".
"Mental health service providers take this very seriously and the way these incidents are dealt with has improved."