The number of people age 65 and up involved in marijuana-related emergency room visits in California jumped from 2005 to 2019, according to new research.

The study found the number of marijuana-related ER visits among seniors in California rose from 366 in 2005 to 12,167 in 2019 – an increase of 1,808%, HealthDay reports. California legalized medical marijuana in 1996 and recreational marijuana in 2016.

The researchers said older adults are at increased risk for adverse health effects associated with marijuana such as dizziness and falls, heart palpitations, panic attacks, confusion, anxiety or worsening of underlying lung diseases, such as asthma or COPD.

“Many patients assume they aren’t going to have adverse side effects from cannabis because they often don’t view it as seriously as they would a prescription drug,” study author Benjamin Han, M.D., said in a news release. “I do see a lot of older adults who are overly confident, saying they know how to handle it — yet as they have gotten older, their bodies are more sensitive, and the concentrations are very different from what they may have tried when they were younger.”