One-fifth of people who use marijuana have some degree of cannabis use disorder, a new study finds.

Cannabis use disorder is defined as problematic use of cannabis that leads to symptoms including recurrent social and occupational problems, indicating impairment and distress, The New York Times reports.

Researchers studied nearly 1,500 primary care patients in Washington State, where recreational use is legal. They found that 6.5% of people who use marijuana had moderate to severe cannabis use disorder.

The researchers found 42% of people using marijuana said they used cannabis only for medical reasons, while 25% said they used cannabis recreationally, and 32% said they used cannabis both medically and recreationally.

The study found people who had more severe marijuana dependency tended to use cannabis recreationally, while less severe but still problematic marijuana use was linked equally with medical and recreational use.

The study found the most common symptoms of cannabis use disorder were increased tolerance, craving and uncontrolled escalation of cannabis use.