John Healey’s survey of local schools in 2018 found nearly all had seen mental health worsen.
He took local headteachers to see the schools minister, which helped win £1.7m from the government for extra mental health support.
John, who represents Wentworth and Dearne, said: “The number of children experiencing mental health problems is increasing and I know through constituency casework how hard parents find getting help.
“Our mental health services are stretched to breaking point and have long waiting lists.”
More than a third of children referred to mental health services were turned away last year.
Many more kids are being referred to the council’s Child and Adolescent Mental Health Services (CAMHS) and some are waiting years for treatment, according to the MP.
At the Labour Party conference in Brighton last week, leader Keir Starmer guaranteed access to mental health treatment in less than a month for all who need it.
John added: “The current crisis in mental health services means two in five patients waiting for mental health treatment are forced to contact emergency or crisis services prior to receiving treatment, with one in ten ending up in A and E.
“A quarter of adults who had to wait after their initial assessment did not begin treatment for three months or more.”
A report was issued to Barnsley Council by health bosses outlining a more collaborative approach to tackling cases of mental health issues and self-harming in schools.
It said: “The past year was marked by unprecedented challenges related to the Covid-19 pandemic and the series of national lockdowns which impacted upon all agencies and staff working with children and families, service delivery and on the wellbeing and safety of many children and families.
“There were increased concerns about ‘hidden harm’ for vulnerable children and young people with reduced schools’ attendance and contact with professionals, as well as frequent disruption to children’s education with the concern about how this might impact upon their outcomes.
“We know from a survey undertaken in Barnsley that young people reported much higher rates of anxiety and mental health concerns during the pandemic because of isolation from peers and the change to their routines.
“Children’s social care and South Yorkshire Police reported increased referrals, particularly in relation to incidents of domestic abuse and neglect during the past year and all agencies experienced staffing and resource pressures during the pandemic.”