Vikki McGovern died at the age of 19 after taking the heroin substitute in 2008 at St John’s Hill, in the Dumbiedykes area of the city.
Jamie Whitson, 33, is now being tried for supplying her with the substance, allegedly knowing she would attempt to commit suicide with it.
At the High Court in Dundee yesterday, 41-year-old Pamela Bowmaker, the victim’s mother, said her life went off the rails following the death of one of her friends.
She added that she had feared for her daughter’s prospects after becoming mixed up with a bad crowd at an Edinburgh hostel she was staying in.
“She stayed on at school for fifth year and went to college to study care. She wanted to be a children’s nurse,” she said.
“When our friend passed away she started having problems.
“She didn’t really react to the death – she went into herself instead. She went really quiet and that’s when her problems started. Vikki was just a happy-go-lucky person, but after that she started self-harming – cutting herself on her arms.
“She moved into a flat where she had support if she needed it. Then she moved to St John’s Hostel and took time off college with a view to going back later.”
It is alleged that Whitson, charged with culpable homicide, gave her methadone in September 2008.
He also faces a separate charge of supplying methadone to Miss McGovern and another man, Stuart Hedges, at two addresses in Edinburgh between November 12, 2007 and September 18, 2008.
Miss Bowmaker said just months after that move in June 2008 her daughter had tried to kill herself. She said: “In August 2008 she sent me a text saying she was sorry and that somebody had given her methadone and that she was in hospital.
“She said she loved me and her brothers and sisters and that she would never do it again.
“I visited her at her hostel and she said that at the time she had wanted to do it. After that I saw her every day. On September 20 the CID came to my house and told me she had died.”
She added: “I felt St John’s Hostel wasn’t the kind of place that she needed.
“I felt she was meeting people who weren’t being helpful or nice to her – I felt they were taking advantage of her.
“She didn’t like confrontation – she wasn’t that type of person. She was 19 years old and I had never had an argument with her.”
The trial, before Lord Pentland, continues.