Professors at Auburn and San Diego State universities offered students at their respective schools an extra course credit to participate in a study about their workplace habits and performance, going through the side door to learn about marijuana's role on the job.
First, researchers contacted participants' direct supervisors at their workplaces, asking about the employees' well-being, stressors and downtime. In order to protect the job status of the students, who were not required to consume cannabis in order to take part in the study, marijuana use wasn't mentioned to employers. Instead, researchers asked students the marijuana-based questions, such as how often they'd used marijuana before, during or after work within the past year, and then compared their answers about pot to their work supervisor's answers about job performance.
After analyzing surveys from 281 students and their bosses, study results indicated that pot consumption before and during work negatively impacted an employee's ability to complete assigned tasks and perform core duties. However, the study noted that marijuana use off the clock "was not related (positively or negatively) to any form of performance," judging from the ratings of the students' work supervisors.
"Results indicate using cannabis before or during work harmed four of five different dimensions of performance rated by the user’s direct supervisor, yet contrary to commonly held assumptions, not all forms of cannabis use harmed performance," researchers note. "In fact, after-work cannabis use did not relate to any of the workplace performance dimensions. This finding casts doubt on some stereotypes of cannabis users and suggests a need for further methodological and theoretical development in the field of substance use."
The study also highlights the need to differentiate the amount of marijuana consumption and methods of use by participants when they aren't working, explaining that these variables could be the difference between being well rested after a long day or becoming dependent on the plant.
"That is, after-work cannabis use could allow for relaxation and resource recovery to take place, which would help with performance-related aspects of one’s work, but it may be indirect such that after-work cannabis users get better sleep, wake up feeling more energized, and this positive state is what sets the stage for improved performance," the authors write, concluding that "habitual use of cannabis after work for recovery purposes may lead to automatic consumption, an increase in tolerance levels, and risk for substance dependence over time."
Even in Colorado, where recreational marijuana has been legal since 2012, employers are legally able to fire employees for smoking weed after hours; THC, the main intoxicating compound in marijuana, can be detected by drug tests for longer than a month after consumption, in some cases.
A bill introduced in the Colorado Legislature that would have shielded marijuana users under the same law that protects off-hour alcohol and tobacco consumers was quickly killed last year, the focus of loud opposition from business and trade organizations, including the Colorado Chamber of Commerce, several construction organizations and Pinnacol Assurance, the largest handler of workers' compensation cases in the state. At the time, legislators argued for the need for more scientific methods to realistically detect recent marijuana use.
Some states and local governments do have protection for off-hours marijuana use. Nevada's state legislature passed a law last year that bans pre-employment marijuana tests, and New York City also prohibits them. In 2017, the Massachusetts Supreme Court ruled in favor of a medical marijuana patient who argued that medicating off the job wasn't grounds for dismissal.