Have you gotten swept up in the CBD craze? Careful. It may induce a positive drug test.

That’s according to findings from a clinic trial published last month in the journal JAMA Psychiatry. The findings, which comes via researchers at Harvard, “suggest that patients consistently using full-spectrum, hemp-derived products may have positive test results for THC-COOH on a urinary drug screen,” the authors of the study wrote.

“Despite limitations in sample size and diversity, these findings have important public health implications,” the researchers wrote in their conclusions. “It is often assumed individuals using hemp-derived products will test negative for THC. Current results indicate this may not be true, especially if assays are more sensitive than advertised, underscoring the potential for adverse consequences, including loss of employment and legal or treatment ramifications, despite the legality of hemp-derived products.”

The findings also help fill a gap in what the authors said has been a paucity of research on CBD.

“Despite the growing popularity of cannabidiol (CBD) products, specifically those derived from legal industrial hemp sources,” the authors said, “few studies have directly assessed whether the use of high-CBD products could yield positive results on urinary drug tests assessing cannabis use through the detection of [THC] metabolites.”

The Study

The study was conducted at McLean Hospital in Belmont, Mass. between June of 2018 and February of this year with 15 participants, all of whom were 18 and older. Those patients “self-administered 1 mL of the study product sublingually 3 times per day, for a targeted daily dose of approximately 30 mg of CBD,” as well as less than one milligram of THC.

That last part is crucial. In its own write-up of the study, NORML noted that the “ingestion of CBD products absent any presence of THC will not trigger a positive drug test result because CBD is not converted into carboxy-THC following metabolization.”

The authors added, as quoted by NORML: ““[T]hese findings have important public health implications. It is often assumed individuals using hemp-derived products will test negative for THC. Current results indicate this may not be true, especially if assays are more sensitive than advertised, underscoring the potential for adverse consequences, including loss of employment and legal or treatment ramifications, despite the legality of hemp-derived products.”

The 2018 Farm Bill legalized hemp cultivation, and facilitated CBD production. As the Brookings Institute explained, the legislation did not legalize CBD, but ensured “that any cannabinoid—a set of chemical compounds found in the cannabis plant—that is derived from hemp will be legal, if and only if that hemp is produced in a manner consistent with the Farm Bill, associated federal regulations, association state regulations, and by a licensed grower.” 

After the Farm Bill’s passage, a number of states followed suit and passed laws allowing hemp cultivation within their own borders. 

A bipartisan bill introduced in the House of Representatives in September sought to allow hemp to be sold as a dietary supplement. Rep. Morgan Griffith (R-VA), one of the bill’s co-sponsors, hailed hemp as a boon for farmers in the commonwealth.

“Hemp was historically an important crop for Virginia farmers, and dietary supplements made from it do not possess dangerous addictive qualities,” Griffith said. “Nevertheless, the current state of regulation creates confusion about its legal uses. I joined this bipartisan bill to provide certainty for hemp farmers that their crop may find legal uses.”