Use of LSD grew by more than 50% in the United States between 2015 and 2018, according to a new study.

Researchers at the University of Cincinnati analyzed data collected from more than 168,000 American adults by the National Survey on Drug Use and Health. They found past-year LSD use rose by 56% over three years.

Increases were most pronounced among people with college degrees and those ages 26 and older. Young adults ages 15 to 25 decreased their use of LSD by 24% during that period, the researchers report in Drug and Alcohol Dependence.

Overall, LSD use remains low, the article notes. The number of Americans using LSD in a given year remains less than 1% of the total adult population.

“LSD is used primarily to escape. And given that the world’s on fire, people might be using it as a therapeutic mechanism,” lead research Andrew Yockey told Scientific American. “Now that COVID’s hit, I’d guess that use has probably tripled.”