Chao shows two holes in his groin from injecting drugs on June 21, 2012 in a rehabilitation center at the Chenzhou Mental Hospital, Hunan province. [Photo/ Xiaoxiang (Changsha) Morning News]

He injected heroin four times a day into his groin vein, which is the most dangerous way of taking drugs, known by users as to "open a scuttle".

The pain of addiction tortured Chao, making him irritable especially when he started his rehabilitation.

Staff at the center had to bind his hands to a bed to prevent him from breaking things, Xiao Bing, a doctor at the center said, but added that "Chao's young age made it him easier for him to quit drugs." Just one month after receiving therapy, Chao weighed five kilograms heavier. On June 20, Chao admitted, "I completely don't want drugs anymore."

He now hopes to go to school and enjoy the things children at his age should.

On June 21, he told his psychologist Huang Yan: "I smoke, speak dirty words which are all bad habits of adults. But I'm a nearly a teen; I should have the bad habits of a child. I envy those children."

Staff at the center said Chao could leave when he has finished his treatment and they are trying to contact his relatives to give him the best chance of recovery.

"I will never take drugs again, but I may end up stealing things if no relatives can look after me, " he added, "Everyone walks a different way, the key is how you are brought up."

His words astonished all who listened.