Mental health charities have called for an immediate end to the face-down restraint of patients, which is being used disproportionately on women and girls.

Organisations including Mind, Rethink Mental Illness, YoungMinds and Agenda say the practice is “frightening and humiliating” and “re-traumatises” female victims of violence and sexual abuse.

In an open letter to Jeremy Hunt, the health secretary, the charities point to evidence provided by Agenda, the alliance for women and girls at risk, revealing that patients are regularly restrained in some mental health units but others deploy non-physical means of calming patients or stopping acts of self-harm.

The letter states: “Given that more than half of women who have mental health problems have experienced abuse, restraint not only risks physical harm and can be frightening and humiliating, but being restrained, particularly face-down, can also re-traumatise those with a history of violence and abuse. Mental health units are meant to be caring, therapeutic environments, for people feeling at their most vulnerable, not places where physical force is routine.”

The latest government guidelines on restraint, from 2014, suggest face-down should not be used and that all other forms of physical restraint should be a last resort. But Agenda’s research found that one in five women and girls admitted to mental health units had been physically restrained and that they were more likely than men to be subjected to such treatment. Some trusts reported an average of more than a dozen face-down restraints per female patient.

In adult services, more than 6% of women – nearly 2,000 – were restrained face-down a total of more than 4,000 times. The figures exposed wide regional variations in the use of the practice.

Philippa Lalor has suffered mental health problems for more than a decade, with spells in several hospitals and units. She said that in some units, staff would subject her to face-down restraint two or three times a day. “I became extremely angry – it affects your relationship with the whole mental health system,” she said. “I felt worthless. I have a life and friends and all the normal things – people know I have mental health problems but I would never tell people I have been restrained in the way I have, it sounds so awful and it is so shameful. It’s only in the last year that I have started to recognise that I can’t blame myself.

“It can be mental health-trained nurses along with healthcare assistants, anyone – up to a team of eight people. It’s used to prevent self-harm and suicide. It is very painful. When you are face down you have only two options: your head goes into the floor, painfully; or you twist your head round 90 degrees, to an angle your head isn’t supposed to go. I have lifelong neck pain from it. I was once subjected to it because I threw an orange on the floor.

“Interestingly, when I had perhaps my most severe [problems], I was in an acute ward where they didn’t use restraint, they de-escalated the situation without restraint and did it professionally and properly.”

Agenda produced last week’s report after freedom of information disclosures from 51 of the 58 mental health trusts in England. Director Katharine Sacks-Jones said that trusts were clearly using restraint when alternatives were viable.

“Face-down restraint is something that is raised again and again as a traumatic experience by women we speak to,” she said. “We have cases of it being carried out by male nurses, in cases where a woman doesn’t want to take medication. If you are a woman who has been sexually or physically abused, and mental health problems in women often have close links to violence and abuse, then a safer environment has to be just that: safe and not a re-traumatising experience.

“Of course, there may be extreme situations where physical restraint needs to be used, of course there may be incidents where it is the only option, but there are trusts where it is used hardly at all and places where it is seemingly routine. Face-down restraint hurts, it is dangerous, and there are some big questions around why it is used more on women than men.”