In 2012/13, 26 per cent of people seeking an initial assessment for drug treatment were over 40, up from 15 per cent in 2006/07.
The Scottish Government said it was encouraging to see that older drug users were seeking help.
The official figures are contained in a report on the Scottish Drugs Misuse Database (SDMD). It found that since 2006/07 "an increasing proportion of individuals from older age groups" have been assessed for specialist drug treatment each year.
In that year, half those coming forward for treatment were aged 30 and over, but the figure has now increased to two-thirds, or 66 per cent, in 2012/13.
The figures also show the overall proportion of people seeking treatment has remained fairly static in recent years.
In 2012/13, 1,861 people had an initial assessment for treatment, a rate of 222 per 100,000 population.
This rate has fluctuated in recent years, but has been stable at approximately 220 per 100,000 population since 2009/10, officials said.
In other findings, across all NHS health boards, heroin, cannabis and diazepam were the illicit drugs most frequently reported to have been used in the past month.
In the majority of health boards, the percentage of people reporting heroin as the main drug they used in the past month was also down from 2011/12 to 2012/13. Furthermore, between those two years, reported heroin use among under-25s reduced across almost all NHS boards.
A Scottish Government spokesman said Scotland was dealing with a long legacy of drug use. He added: "It is therefore encouraging to see that there is an increase in the number of older drug users engaging in treatment to support their recovery."