In 2012/13, 26% of people seeking an initial assessment for drug treatment were over 40, up from 15% in 2006/07.
The Scottish Government said it was encouraging to see that older drug users were seeking help on the road to recovery.
The official figures are contained in a report on the Scottish Drugs Misuse Database (SDMD), which provides information on people contacting specialist services in 2012/13 for an initial assessment for a new drug treatment episode.
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%, in 2012/13.
The figures also show that the overall proportion of people seeking treatment has remained fairly static in recent years.
Overall, in 2012/13, 11,861 individuals had an initial assessment for treatment, a rate of 222 per 100,000 population.
While the rate has fluctuated in recent years, it 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 decreased from 2011/12 to 2012/13. Furthermore, between those two years, reported heroin use among people under the age of 25 reduced across almost all NHS boards.
A Scottish Government spokesman said: "In Scotland, we are dealing with a long legacy of drug use and while this is declining among young people and the general adult population, we know there is a vulnerable group of people who have been using drugs for many years.
"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."