For the first time ever, the United Nations (UN) is launching an in-depth review of whether marijuana is properly classified under international drug treaties.

In a related development, the UN’s World Health Organization (WHO) has announced that cannabidiol (CBD), a compound in marijuana that is increasingly used for medical purposes, does not warrant being controlled under the global agreements.

“The Committee recommended that preparations considered to be pure CBD should not be scheduled within the International Drug Control Conventions,” WHO Director-General Tedros Adhanom Ghebreyesus wrote in a letter announcing the moves. “The Committee concluded that there is sufficient evidence to proceed to a Critical Review” of marijuana, hashish, cannabis extracts and THC.

That broader review is set for November, and follows the results of an initial pre-reviewconducted by WHO’s Expert Committee on Drug Dependence (ECDD) in June.

“A pre-review is the first step of the ECDD’s assessment process, where it is determined whether there is enough robust scientific information to proceed to the next step, called a critical review,” an explanatory document accompanying the new letter reads. “This initial evaluation is also an opportunity to identify gaps in the available scientific data. A critical review is carried out when there is sufficient scientific evidence to allow the ECDD to make informed an recommendation that the substance be placed under international control, or if its level of control should be changed.”

The reviews include analyses of the chemistry, pharmacology, toxicology, epidemiology and therapeutic use of the substances.