Labour MP Luciana Berger told Theresa May the state will have “blood on its hands” if mental health services were not improved for young people.
The Liverpool Wavertree raised the case of a “desperately ill” 17-year-old girl who had been restrained 117 times while in secure custody.
Sir James Munby, head of the family courts in England and Wales, had said he was “ashamed and embarrassed” the state could not find a bed for the girl, known as X.
A last-minute bed was found for the girl in August.
Berger told MPs “A few weeks ago, the utterly shaming lack of mental health provision in this country was condemned by our most senior family court judge as he sought a bed for a desperately ill teenage girl.
“The 17-year-old has been restrained no fewer than 117 times in a place not fit to care for her.
“Does the Prime Minister agree with me in echoing the words of Sir James Munby that the continued failure to tackle our nation’s mental health crisis means that the state will have blood on its hands?”
The Prime Minister replied she had been “concerned” to read about the case and that the government was more money and had introduced programmes focusing on the mental health of young people.
She added: “I accept that we need to do more in relation to our mental health services.”