Alison and Tim Hysom joined Detective Inspector John Delaney at Ilford police station to appeal for the public's help in finding their 15-year-old daughter.
DI Delaney added: "We are taking this matter seriously and a lot of resources, including search teams, have been deployed. We are concerned for her welfare because she is vulnerable, she is suffering from depression and she is just 15.
"It is out of character and there has been no contact from her since the day she went missing."
More top news
Declan Donnelly will host the show alone when the show returns on March 31 following his partner Ant McPartlin's return to rehab, ITV says.
The campaigners have raised concerns about former undercover officers being granted anonymity during the proceedings.
The Discovery School in Newcastle has said there was "no excuse" for the serious error.