As marijuana dispensaries open, sales of over-the-counter (OTC) sleep remedies go down, suggesting that many people suffering with insomnia prefer to self-treat with cannabis than to take pharmaceuticals. The study, published in the journal Complimentary Therapies in Medicine, assessed sales of OTC sleep aids before and after Colorado passed laws legalizing recreational marijuana.

The market share of sleep aids compared to all OTC drugs was growing before the legalization of recreational cannabis, but when dispensaries opened, the trend reversed, with the market share dropping 236%.

These findings support evidence that many people use marijuana to treat insomnia, even though it’s not a specific qualifying condition under any state medical marijuana law.

According to the authors of the study, the results suggest that “at least some recreational purchasers are using cannabis for therapeutic rather than recreational purposes.”