Too stoned to work? Frequent cannabis users prone to absenteeism, UC San Diego study shows

A researcher from UC San Diego and a colleague from New York University have released the results of new study linking workplace absenteeism with cannabis use.

According to the report, which was published Monday in the American Journal of Preventive Medicine, more than 46,000 full-time workers from 2021-22 participated in a study that showed that "recent and frequent cannabis use and cannabis use disorder (CUD) were associated with greater workplace absenteeism."

The study, which was penned by Dr. Kevin H. Yang, a third-year resident in the Department of Psychiatry at UC San Diego School of Medicine, and Joseph J. Palamar, Ph.D, M.P.H, an associate professor in the Department of Population Health at New York University Grossman School of Medicine.

What's CUD? It's when people persist in consuming cannabis even though their usage has a "significant negative impact on one's life and health," according to Yale Medicine, and "costs the U.S. employer-sponsored insurance population an estimated $4.7 billion annually in medical expenses," according to the study published Monday.

On Monday, NBC 7 spoke to Yang, who was in Big Bear, where the Alabama native and third-year resident in the Department of Psychiatry at the UC San Diego School of Medicine was vacationing when the AJPM published his co-authored report.

"I have no control over that," Yang said with a laugh, referring to this week's time off.

There's a lot of drug research at UC San Diego going on, Yang told NBC 7, with researchers interested in cannabis use, which has increased dramatically in the past 10 years or so, given changes in legalization and increased permissiveness in society.

"We look at public health, various public health aspects of cannabis use and also of psychedelic use, looking at both the positive and the negatives of such use from a public health perspective," Yang said.

The data from the new study shows that 15.9% of full-time workers used cannabis in the prior month, with 6.5% of those workers "meeting the criteria" for CUD. In that period, "the mean number of workdays missed because of illness was 1.47 for people who didn’t have CUD but had used cannabis within the past month." The number was significantly smaller — 0.95% — for people who have never used the drug before."

The number of missed workdays was self-reported by the study's participants, researchers said. Yang said their analysis did not look into how many people overall used cannabis in the prior month, "so it's unclear whether this is more or less than the general population. It's not something that we looked at."

Although occasional cannabis use was associated with work absences, people experiencing CUD had a "1.30-2.87 times higher incidence of missing or skipping work compared to those without CUD," the researchers' analysis shows.

So, the mean number of days for someone experiencing CUD could be as high as 4.22 work days a month (1.47 x 2.87=4.22).

The researchers' conclusion: "Individuals with recent and frequent cannabis use and CUD are disproportionately prone to workplace absenteeism." Some of that missed work is due to illness or injury connected to cannabis use, according to the study, and, potentially exacerbating the issue, "individuals who are injured or experienced health issues may turn to cannabis for self-medication purposes, potentially exacerbating the cycle of absenteeism."

Yang said that their analysis revealed a pattern of behavior among users of cannabis (missing work) and does not necessarily show that that behavior is specifically caused by cannabis use. In other words, what the study shows is that cannabis users miss work more frequently than employees who don't use the drug.

"It's unfortunately something that we would need to do more research on to kind of better understand what the directionality of it is," Yang said Monday. "The study is a cross-sectional study, so we're just looking at it in one cross-point in time. It's kind of a chicken-or-the-egg question in terms of, you know: Does cannabis use cause these people to miss work or are people who are more likely to miss work more likely to use cannabis as a result? So we don't have those answers. The study isn't able to answer that question, but it certainly, you know, it suggests that we need to do more research potentially looking at longitudinal studies and also qualitative studies, aka interviewing these patients, to see why they're missing work and also why they're using cannabis."

And how does being too stoned for work compare with, say, alcohol abuse? The researchers say that workers with severe alcohol use disorder (AUD) are nearly two to three times more likely to miss three days of work or more a month than those without AUD.

Researchers said in their conclusion that their results "support the enforcement of workplace drug prevention and treatment policies."