New York’s medical marijuana program will now cover chronic pain as a qualifying condition, the Department of Health on Thursday announced in what is the most significant expansion of the program since its creation.

“After conducting a thorough review of the scientific literature, it became clear that there may be certain benefits in the use of medical marijuana by patients suffering from chronic pain,” said Health Commissioner Dr. Howard A. Zucker. “Medical marijuana is already helping thousands of patients across New York State, and adding chronic pain as a qualifying condition will help more patients and further strengthen the program.”

The DOH is developing regulatory guidelines for adding chronic pain, including language that will outline conditions that qualify for medically based cannabis.

The move is expected to aid medical marijuana manufacturing companies that have seen relatively slow growth since the program began in New York in 2015.

Previously state officials had outlined guidelines for medical marijuana that limited prescriptions to patients with terminal illnesses, but had never closed the door to an expansion.

The addition of chronic pain to its qualification list comes as state health officials have also moved to allow physician assistants and nurse practitioners to certify patients for medical marijuana.

The nurse practitioner regulation took effect today, while the PA regulations are to be finalized in the next 45 days.