Artist Alison Lapper has hit out at "appalling" mental health care after revealing school bullies contributed to her son's struggles before his death.
Parys Lapper was 19 when his body was found in a Sussex hotel last month.
His mother posed nude while pregnant with him for a piece of artwork which was mounted on the fourth plinth in London's Trafalgar Square in 2005.
Ms Lapper was born with no arms and shortened legs, which she said became an issue for her son at school.
She told BBC Radio 4's Today programme Parys's mental health problems began when he started at secondary school in Sussex and pupils would give him strange looks because of her disability.
"The teenage years kicked in. He went from a small school to a massive school which I think had an impact," she said.
"We all know teenage years are hard; they change. I could just see my happy kid just disappearing in front of my eyes and not knowing what to do.
"I know he got into a fight and he punched someone because they said something about him or myself.
"That wasn't Parys. He didn't go around punching people but obviously that triggered something."
Parys was sectioned at 17 years of age and had treatment in Sevenoaks, Kent.
Ms Lapper says she tried to have him moved back closer to her home in Sussex but he was moved to an anorexia unit instead.
"What good is that to someone who doesn't have anorexia?" she said.
"There are no provisions for young people who are suffering from mental health problems.
"The people who worked with him tried their best but the facilities out there are appalling."
Ms Lapper said she had been with her son just days before he died. His funeral was held on Thursday.
She said: "I miss him. I'm absolutely heartbroken. I feel like he has been let down."
If you or someone you know are feeling emotionally distressed, these organisations offer advice and support. In addition, you can call the Samaritans free on 116 123 (UK and Ireland). Mind also has a confidential telephone helpline- 0300 123 339 (Monday-Friday, 9am-6pm).