A star pupil who was head boy at his Catholic school died after taking LSD at a birthday party.
Matthew White, 18, from Cardiff, is believed to have hanged himself in woodland after taking two tabs of the drug.
The teenager had passed 10 GCSEs, some at A* grade, but started drifting away from his family when he took up smoking cannabis.
His mother, Colette, from the St Mellons area of the city, said Matthew, who was a brother to Martin, 16, and 22-year-old Christopher, had not continued his studies but was working as a carpenter before his death.
He had started sleeping in woodland in the Leckwith area of Cardiff, sharing a makeshift shelter with friends. But at midday on January 20, the day after celebrating a birthday, they found his body hanging from a tree.
Mrs White told the South Wales Echo: "Matthew came from a good home and he had a good upbringing. He just drifted off the rails.
"You hear about these events happening to other people, you never think it's going to be you.
"Why is cannabis regarded as a soft drug? It changed my son's life. Matthew's been stolen from us and he had everything to live for."
She said her son was a big, friendly giant with warm, blue eyes, and that he had been a popular boy.
Matthew had talked of becoming an architect and excelled at art. He was involved in school drama productions, played instruments including the guitar, banjo and mandolin, and wrote his own music.
Mike Worthington, headteacher of St Illtyd's Catholic High School in Cardiff, said Matthew's death had come as a huge shock.
He said: "Our school community is very upset, and personally I am very upset. All our prayers are with his family.
"It is an enormous tragedy. He was such a nice boy, a really likeable lad. There is nothing negative to say about him.
"The only thing that could be learned from this is that once you get hooked, it's a hard struggle, and you can't get out easily.
"People with alcohol and cigarette problems get support, but this is such a taboo issue. We tend to brush drugs under the carpet. Things need to be more open."
Matthew, who left the school in 2005, had been selected as head boy by pupils and staff.
Mr Worthington added: "All the boys and girls looked up to him. He was just a hard-working soul who people respected because of his attitude. He was a very eloquent man who could stand up for the school and make speeches.
"The sad thing is that it's all gone, but I know he's at peace now."Reuse content