NEW HAVEN, Conn. (WTNH) — One Yale doctor is urging caution to seniors who are considering using cannabis.

Cannabis became legal in California in 2016. Since then, the number of older people visiting emergency rooms due to complications from the substance has skyrocketed.

In Connecticut, recreational sales began earlier this year.

Yale’s Dr. Deepak D’Souza said that a lot of research has surrounded cannabis use — but that the studies have only involved people between the ages of 21 and 35.

D’Souza, who leads the new Yale Center for the Science of Cannabis and Cannabinoids, said that there’s been a 75% increase nationwide in people 65 and older using cannabis.

He emphasizes that elders have declining attention, memory and motor coordination.

“It’s conceivable that older people under the influence of cannabis may be more vulnerable to motor vehicle accidents,” D’Souza said.

There are also potential dangers with using cannabis alongside prescriptions like sleeping medications, or cardiac and psychiatric medications. He urges seniors to consult with their doctors or pharmacists before using cannabis.

He said that the cannabis sold at dispensaries now is more potent than what’s been available in the past.

“Don’t think it’s going to be the same as what it was you smoked in your 20s and 30s,” he said.

He advises checking the label for the cannabis’ THC content, noting that the average cannabis content in the 1960s was 4% or less. Nowadays, it’s 17% or more.

And for those who decide to give it a try, he said to start slow and with a low THC content before proceeding.