A woman who says she was raped more than 50 times while at an NHS psychiatric hospital has told BBC Radio 5 live such institutions are an "open playing field for predators".
Catherine told the Victoria Derbyshire programme about being an in-patient at Little Brook Hospital, Kent, several times in 12 months in around 2003.
She said she was groomed and repeatedly raped by a care worker at the hospital.
A man was later convicted of one count of unlawful intercourse with a patient.
'I was open to abuse'
Catherine said it was the result of a nervous breakdown and developing anorexia, after getting out of a 10-year abusive relationship, that she was admitted to the Dartford hospital.
The abuse began within days of her arrival, the mother-of-two said.
"I was on a very heavy amount of Valium, not to where I was unconscious, but add the sedative effect to my already defeated self, I was putty.
"He came in my room, pulled the covers back, got on top, did what he had to do and left... all over very quickly. I didn't murmur... didn't move."
She added: "Very quickly it became every night he was on shift I would expect it."
Asked if she knew why she had not offered resistance, Catherine said: "It took me a couple of years after to understand why... I asked myself that every day for a couple of years.
"I was a defeated person. I wasn't able to care for myself, I wasn't washing, I wasn't feeding myself - I was like an abused dog that if you went up to and gave another kick to she wouldn't have flinched.
"If someone had come into my room with a knife and stabbed it in me, I don't think I would have flinched. I was in a bad way, and therefore I was hugely open to abuse."
Her abuser also told her he could help secure her discharge from the hospital if she complied with his demands, she said.
"There was no point me telling anybody. Who's going to believe a mental patient - a mental in-patient - over a longstanding member of staff who was seemingly highly respected and regarded by his colleagues?"
Several years after leaving the unit, Catherine told a community psychiatric nurse what had happened and the care worker was immediately arrested.
In 2008 he pleaded guilty to one count of unlawful sexual intercourse with a patient and was sentenced to 12 months in prison, suspended for two years.
He was also told he could never work with vulnerable people again. Catherine received a letter of apology from Kent and Medway NHS Trust and £100,000 in compensation.
But this is the first time she has ever spoken publicly about what happened to her.
Catherine described psychiatric hospitals as a "playing field for predators".
She said: "It's a group of people who are probably the most vulnerable in society with regards to being open to abuse and then subsequently being believed.
"It is an open playing field for predators in that environment. Who is going to speak up when they have been in a mental health institution?
"There is a stigma, you are ashamed, it's not something you tell people. To then say that a member of staff raped you... it's probably one of the hardest things I've ever done, and yet I was believed and that was wonderful."
However, she also recalled the judge saying he was only able to sentence in relation to one offence.
"[That] again reinforces that [in terms of] mental health... you are deemed not quite a first-class citizen," she said.
"You are a second-class citizen so therefore it doesn't matter so much. One time, 50 times, it doesn't matter."
The Crown Prosecution Service told the BBC that in cases where multiple allegations were made it was common for a trial to consider a single specimen case.
The way allegations of sexual assault are dealt with have changed substantially since 2003.
New sentencing guidelines, under which sexual activity with a person with a mental disorder can carry a life sentence, are due to come into force in April.
Kent and Medway NHS and Social Care Partnership Trust, which runs Little Brook Hospital, told the BBC it could not comment on Catherine's case because it happened before the formation of the trust.
But it pointed out that all staff undergo "an enhanced Disclosure and Barring Service (DBS) check" before they can work in such a unit.
Some names have been changed to protect the privacy of individuals.