In states with medical cannabis laws, 30% of adults with chronic pain report using marijuana to manage their pain, according to a new study.

Most people who used marijuana as a treatment for chronic pain said they substituted cannabis for other pain medications, HealthDay reports. More than half reported that use of cannabis led them to decrease use of prescription opioid, prescription non-opioid and over-the-counter pain medications.

In addition, 39% reported their use of cannabis led to decreased use of physical therapy, 19% said it led to decreased use of meditation and 26% said it led to decreased use of cognitive behavioral therapy.

The study included more than 1,600 people with chronic pain not related to cancer.

The survey results “really underscore the need for research on the benefits and risks of using cannabis for chronic pain,” lead researcher Dr. Mark Bicket of the University of Michigan School of Public Health. “Cannabis is accessible as a treatment for chronic pain for most adults in the United States, but we don’t know how safe and effective cannabis is for chronic pain.”