Six in ten children who attended Child and Adolescent Mental Health Services (CAMHS) in the past year had difficulty accessing the service and nearly half of those individuals said the service that they finally received did not help with their mental health issues, according to a report.
The Children's Ombudsman on mental health surveyed 2,166 children aged between 12-years-old and 17-years-old.
The 'A Piece of my Mind' report identified long waiting times as the biggest challenge in accessing CAMHS and many people found that the service failed to address their needs.
Over a quarter of children believe that CAMHS staff were dismissive of them, while only 11% believed that staff listened to them.
The online survey also noted that 78% of children said they have experienced some form of mental health difficulties.
Of the children surveyed for the report, 6% were using CAMHS at the time with 12% having accessed CAMHS at some time.
The top five causes of mental health difficulties for children were pressure in school (74%), body image (65%), friendships or relationships (61%), social media pressure (48%) and bullying (47%).
More girls than boys struggled with their mental health (55% to 44%), while of the 6% of non-binary children or those who identified as other, almost all (94%) said they had some sort of mental health difficulties.

Commenting on the findings, the Ombudsman for Children, Dr Niall Muldoon, said: "We must remember that for children to have to turn to CAMHS in the first place they have to be really struggling with their mental health."
"So, it simply isn't good enough that so many of them are having to wait long periods of time to access services, and that when they do, they feel that the standard of those services falls short," he added.
Dr Muldoon said: "The children surveyed emphasised the need to have proper mental supports available to them in school. This is something the OCO has been calling for, and we welcome recent plans from the Department of Education for a pilot programme in primary schools."
However, he warned that the report's findings were downcast.
"Overall, the picture painted by children in this report, particularly around mental health services, is very worrying," Dr Mildoon said.
"With almost 12,000 children on waiting lists for primary care psychology services and 4,270 of those waiting for more than a year, it is an issue that needs to be addressed urgently," he added.