Finnish residents used well over 300kg of amphetamines in 2018, according to wastewater tests carried out by the National Institute for Health and Welfare (THL).
A similar study carried out two years ago suggested that just 200kg of the stimulant was used in the country. The agency estimates that amphetamine use in the country is the highest its ever been.
"Amphetamine is a key drug in Finland," Teemu Gunnar, the head of THL's forensic toxicology unit, said, noting it is classified as very dangerous substance.
THL periodically measures the levels of drugs in the wastewater of 10 of Finland's biggest municipalities - a forensic resource that helps researchers follow the drug habits of about 40 percent of the country's population.
Kouvola tops list
Residents in the southeastern city of Kouvola used the most amphetamines of all the cities examined, while the capital Helsinki was at the top of the list for overall drug use.
The watchdog's previous survey found that cocaine use is also on the rise, but is less commonly used outside larger cities in southern Finland. Methamphetamine levels were also found to be significantly higher in 2018 than they were two years ago.
THL recently published results of a survey which found that amphetamine experimentation had doubled since 2010.
That survey found that four percent of 15-24 year olds had already tried amphetamines, while half of that age group said they had used cannabis.