A literature review of 47 studies found that nearly half of cannabis users met criteria for cannabis withdrawal syndrome. The review was published in The Journal of the American Medical Association.
Although cannabis is typically seen as a relatively safe drug, research has pointed to various risks associated with regular use. Short-term risks include memory impairment and paranoia and long-term risks range from addiction and cognitive impairment to suicide. More recently, researchers have identified the presence of cannabis withdrawal syndrome (CWS) in a subset of regular users.
Despite the emerging evidence of CWS, little is known about the prevalence or risk factors associated with its occurrence. “Cannabis withdrawal is a fascinating topic. We were not certain on the prevalence or risk factors for cannabis withdrawal, which was the basis of the study,” said study author Anees Bahji, an addiction psychiatry fellow at the University of Calgary.
The researchers consulted 8 electronic databases and ended up with 47 studies that met criteria to be included in their review. All studies included a validated assessment of CWS or CWS symptoms. In total, the studies involved 23,518 participants, 69% of whom were men. The studies involved 50 different cohorts; half of them were users seeking treatment and most (76%) were from North America.
The meta-analysis revealed an overall prevalence of cannabis withdrawal syndrome of 47%. The researchers further analyzed the results by study setting, to see if the likelihood of CWS differed depending on the sample used in the study. The highest prevalence of CWS (87%) was found in inpatient samples. Outpatient samples had a prevalence of 54% and population-based samples had a 17% prevalence of CWS.
“The finding that the prevalence of CWS was substantially higher in clinical populations—particularly inpatient samples—is consistent with the notion of a bidirectional association between cannabis use and mental health disorders . . . This finding may indicate that people with CWS are more likely to present to clinicians for help compared with those without CWS, notwithstanding the fact that CWS can be diagnosed and untreated,” Bahji and colleagues say.
Additionally, those who reported using cannabis daily, those who were diagnosed with cannabis use disorder, and those who had comorbid tobacco or drug use showed a higher prevalence of CWS. There was no evidence that the likelihood of CWS differed by sex, age, race/ethnicity, or comorbid psychiatric disorder.
The findings suggest that almost half of regular marijuana users will experience cannabis withdrawal, something the authors say many people are unaware of.
“Cannabis withdrawal appears to be highly prevalent among people who consume cannabis regularly, or who are heavy consumers. Clinicians should be aware of its existence so that they can provide support to people who are considering cessation of or reduction in cannabis use. The literature suggests that cannabis withdrawal may be a driver of continued use, so there is a need to identify effective ways of managing cannabis withdrawal,” Bahji told PsyPost.
A limitation of the study is that its goal was to compare study-level trends and, therefore, differences at the individual-level were not explored.
“As a meta-analysis of previous studies, the approach we took in this study was to get a sense of the ‘overalls’. However, by synthesizing information across studies, the issue of heterogeneity emerges,” Bahji explained.
“When there are differences across studies, we tried our best to determine contributors to this. However, there is still a lot of heterogeneity in the prevalence, so the question of individual variability is still a good one for future research to explore. There might also be a role for determining how the intensity of cannabis (e.g., % THC) may factor into the experience of withdrawal.”
Still, the study was the first meta-analysis to explore cannabis withdrawal among regular users of cannabis and provides compelling evidence for the prevalence of CWS.
“Our research hopes to contribute to harm reduction efforts in this field. We also hope that readers of our research can take something useful from our study, either for themselves or people they know. Ideally, we can all become more “cannabis literate” in a sense so that we can get a better sense of the effects of cannabis on our bodies. For example, if one experiences withdrawal, they can give this experience a name and potentially, seek support if they are interested in cessation or reduction of their cannabis use,” Bahji added.
The study, “Prevalence of Cannabis Withdrawal Symptoms Among People With Regular or Dependent Use of Cannabinoids: A Systematic Review and Meta-analysis”, was authored by Anees Bahji, Callum Stephenson, Richard Tyo, Emily R. Hawken, and Dallas P. Seitz.