Even scientists who wish to conduct research on cannabis in states where it is legal may risk their DEA licenses or federal funding by performing that research. All cannabis used for government-sanctioned research must be obtained through the NIDA Drug Supply Program, and NIDA’s sole source of marijuana is the University of Mississippi. As a result, researchers are limited in the types, strains, compositions, and forms of the cannabis that they receive to study.
They are not permitted to conduct research regarding the potency or other side effects of the various means of ingesting cannabis, or investigate the differences between the various strains of marijuana that appear for sale in the marketplace.
They are not permitted to test the concentrations of the various active ingredients or for the presence of any additives or contaminants in the cannabis that can be quasi-legally purchased in states across the country.
 National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda.
Washington (DC): National Academies Press (US); 2017 Jan 12. Changes in marijuana use across the 2012 Washington State recreational legalization: is retrospective assessment of use before legalization more accurate?
 In 2016, DEA put into place a mechanism by which other private entities could apply for permission to cultivate and distribute research-grade cannabis. Retrieved from Pacula RL, Powell D, Heaton P, Sevigny EL.
Despite dozens of applications being submitted, as of December 2018, no other facilities have been approved. “DEA decision keeps major restrictions in place on marijuana research.”  National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. Assessing the effects of medical marijuana laws on marijuana use: the devil is in the details. Individuals across the country are becoming increasingly able to purchase cannabis in a variety of forms and strengths from quasi-legal entities, including from store fronts, through delivery services, and via a medical prescription.This cannabis cannot be viewed as nor treated as a homogeneous drug or product.The levels of the various active ingredients are extremely varied among different strains and different means of ingestion.What the majority of this cannabis being purchased has in common is that it is not subject to the same research and investigation required of other drugs on the market.As addiction professionals, we have a duty to our clients to educate ourselves on the most up-to-date evidence-based practices.This includes understanding the substances that our clients are using and/or abusing and their respective effects on the body.Background Cannabis is the most commonly used illicit drug in the United States, according to the 2015 National Survey on Drug Use and Health.Although use and possession of cannabis remains illegal pursuant to federal law, state and local governments across the Unites States are increasingly legalizing recreational and medicinal cannabis use.Despite these local laws, possession and use of cannabis remains illegal under federal law pursuant to the Controlled Substances Act of 1970, under which it is classified as a Schedule I drug. implemented strong and effective regulatory and enforcement systems to control the cultivation, distribution, sale, and possession of marijuana," except where a lack of federal enforcement would undermine federal priorities, because of its “expectation that states and local governments that have enacted laws authorizing marijuana-related conduct will implement strong and effective regulatory and enforcement systems that will address the threat those laws could pose to public safety, public health, and other law enforcement interests.” In January 2018, the Cole Memorandum was rescinded by Attorney General Jeff Sessions during Donald Trump’s presidency.Research Obstacles One hurdle cannabis researchers are facing is the legality – or lack thereof – of conducting their research. Drug Enforcement Administration (DEA), institutional review boards, offices or departments in state government, state boards of medical examiners, the researcher's home institution, and potential funders.”  The long and arduous application process serves as a barrier to research, and has been found to discourage cannabis researchers from applying for grant funding or pursuing additional research efforts. Secondly, the NASEM committee found that the barriers to cannabis supply significantly limited the amount and scope of research that is taking place.