Daily marijuana users report more sleep disturbance than people who use marijuana less often or not at all, countering the perception that the drug helps to treat insomnia, according to a new study co-authored by a Boston University School of Public Health (SPH) researcher.
The study, published in January 2016 in the Journal of Addictive Diseases, found that daily marijuana users scored higher on the Insomnia Severity Index and sleep-disturbance measures than non-daily users. Ninety-eight marijuana users, most in their early 20s, participated in the study, which is co-authored by Michael Stein, SPH chair of health law, policy, and management and the study’s principal investigator.
“Better sleep is one of the positive effects that marijuana users swear by, but there has been relatively little careful research on this topic,” Stein says.
In the study, he and colleagues cite previous research indicating that as many as one-third of young adults, ages 18 to 25, complain of sleep problems. The findings show an association between heavy marijuana use and such sleep difficulties.
“The effects of marijuana on sleep in intermittent users may be similar, in part, to those of alcohol, where improvements in sleep continuity measures have been reported with intermittent use, (but) daily use results in the worsening of sleep,” the researchers write.
They find a lack of difference in the sleep characteristics of non-daily users (people who smoked on at least one day in the past month and up to five days per week), compared to non-users. Daytime sleepiness also did not differ among heavy users, lighter users, and non-users.
“Sleep disturbance, which is common in this age group, may not be increased by non-daily [marijuana] use,” the study says. The researchers note that daily users typically reported smoking marijuana in the daytime and at night, while less frequent users smoked primarily at night.
Because the findings suggest that anxiety is “significantly related” to reports of sleep disturbance, Stein and colleagues recommend that future studies look at mood disorders in the relationship between marijuana use and sleep. People with anxiety may be using marijuana to try to mitigate their sleep problems, they say.
The research team urges more study of the issue, so that health providers can talk more clearly to marijuana users about effects on sleep, and drug-treatment providers could “meaningfully target sleep” among heavy marijuana users.
The study was led by Dierdre Conroy of the University of Michigan Addiction Research Center. Co-authors were from Brown University and the University of California, San Diego.