Barbara Bauld, whose son Douglas died in 2017 aged 42, has written to MPs on the Scottish Affairs Committee, which is conducting an inquiry into the country’s drug-death crisis.
According to the most recent figures, there were 934 drug-related deaths registered in Scotland in 2017, the largest number since records began and the highest rate of anywhere in the EU.
Mr Douglas was found dead at his home in Cumbernauld, with a post-mortem examination later establishing that he had traces of illegal and prescription drugs in his body.
Mrs Bauld, a retired teacher, said her son, who suffered from mental health problems, had concealed his addictions due to the stigma attached.
In a submission to MPs, she wrote: “He was so deeply aware of the stigma that he wanted to keep his self-medication secret and that delayed finding any appropriate treatment.
“I feel that it is counter-productive to continue to treat drug addiction as a moral failing, but if we do, as a society, those self-medicating (and at times their relatives) will continue to try to conceal the problem. The stigma feeds the secrecy and encourages a feeling of shame which hinders research into the problem.”
She added: “Had my son got the help he needed, he would have been able to contribute significantly to society. “He was an accomplished computer engineer, a skill for which he won awards and he was someone who could not walk by on the other side of the street if he saw someone else in need of help...
“At his funeral there was standing room only. He was a man I am proud to be able to call my son and I refuse to be ashamed of him.”
MPs are investigating what makes drug misuse in Scotland different from elsewhere in the UK as well as the links with poverty and deprivation.
They will also look at how the UK and Scottish Governments can work more effectively together to tackle the problem.
According to the figures published last year, the 934 recorded drug deaths in 2017 was the highest figure since 1996, with opiates or opioids, such as heroin, morphine and methadone, implicated in nearly 90 per cent of cases.
The overall death rate in Scotland was roughly two-and-a-half times that of the UK.