A sheriff has ruled the death of a man given methadone at a Borders private hospital was "entirely preventable".
Kieran Nichol, 20, was put on the heroin substitute shortly after being readmitted to Castle Craig Hospital at Blyth Bridge in December 2005.
An inquiry heard the valium addict was given methadone after he claimed to be hooked on heroin.
The sheriff said it was "difficult to identify anything that went significantly well" in his treatment.
Mr Nichol spent six weeks "detoxing" at the clinic before discharging himself in October 2005.
Two months later he lapsed back into depression and drug use and his mother Jacqueline Nichol, 49, rang the hospital to ask for her son to be readmitted.
He was taken in the following day, 9 December, but died two days later.
Following a fatal accident inquiry at Edinburgh Sheriff Court, Sheriff Gordon Liddle said in his determination that a "different decision or choice by a number of individuals could have made the difference".
Mr Nichol was given three doses of methadone totalling 90mg within a 24-hour period.
An addictions specialist told the inquiry the dosage was "too high" given the uncertainty about Mr Nichol's tolerance level.
The sheriff said that following the death, the hospital, partly at the insistence of the Care Commission, had made a number of changes.
He also outlined further recommendations in his determination as well as criticising the Crown's failure to lead evidence from those immediately responsible for Mr Nichol at the time of his death.
"There remain questions unanswered," he said.
Mr Nichol's mother said the sheriff had done "all he could at this stage".
"There are still questions which need to be answered and it is about what is best for the public now," she said.
"It shouldn't take until a young man dies before changes are made.
"It has been a long haul but we will keep looking for answers and we are getting there."
A spokesman said for the hospital said it was carefully considering the findings.
"It is a lengthy document and we will ensure that changes that we have implemented since the tragic death in December 2005 are in accordance with the sheriff's recommendations," he said.
"Castle Craig continues to work with the Care Commission to achieve the highest possible standards of care for all our patients.
"In its most recent assessments (April 2010 and May 2009), the commission awarded the hospital a grading of 'very good' in every aspect of service."
He said management and staff remained committed to helping people whose lives had been "blighted by addiction to drink and drugs".
He added: "Since our inception in 1988, we have helped more than 8,000 patients allowing many of them to return to a meaningful role in their personal and family lives."