Prevalence of Cannabis Withdrawal Symptoms Among People With Regular or Dependent Use of Cannabinoids A Systematic Review and Meta-analysis

Questions What is the prevalence of cannabis withdrawal syndrome among individuals with regular or dependent use of cannabis, and which factors are associated with cannabis withdrawal syndrome? Findings In this meta-analysis of observational studies including 23 & x202f;518 participants, the prevalence of cannabis withdrawal syndrome was found to be 47%. Factors that were associated with higher cannabis withdrawal syndrome were clinical settings (particularly inpatient and outpatient vs population settings), concurrent tobacco or other substance use, and daily cannabis use. Meaning Cannabis withdrawal syndrome appears to be common among regular users of cannabis, particularly those in outpatient and inpatient settings and individuals with substance use disorders; clinicians should be aware of the high prevalence of cannabis withdrawal syndrome to counsel patients and support individuals who are reducing their use of cannabis. This systematic review and meta-analysis examines the prevalence of cannabis withdrawal syndrome in individuals who use cannabinoids regularly. Importance Cannabis withdrawal syndrome (CWS)-a diagnostic indicator of cannabis use disorder-commonly occurs on cessation of heavy and prolonged cannabis use. To date, the prevalence of CWS syndrome has not been well described, nor have the factors potentially associated with CWS. Objectives To estimate the prevalence of CWS among individuals with regular or dependent use of cannabinoids and identify factors associated with CWS. Data Sources A search of literature from database inception to June 19, 2019, was performed using MEDLINE, Embase, PsycINFO, Web of Science, the Cumulative Index to Nursing and Allied Health Literature, ProQuest, Allied and Complementary Medicine, and Psychiatry online, supplemented by manual searches of reference lists of included articles. Study Selection Articles were included if they (1) were published in English, (2) reported on individuals with regular use of cannabinoids or cannabis use disorder as a primary study group, (3) reported on the prevalence of CWS or CWS symptoms using a validated instrument, (4) reported the prevalence of CWS, and (5) used an observational study design (eg, cohort or cross-sectional). Data Extraction and Synthesis All abstracts, full-text articles, and other sources were reviewed, with data extracted in duplicate. Cannabis withdrawal syndrome prevalence was estimated using a random-effects meta-analysis model, alongside stratification and meta-regression to characterize heterogeneity. Main Outcomes and Measures Cannabis withdrawal syndrome prevalence was reported as a percentage with 95% CIs. Results Of 3848 unique abstracts, 86 were selected for full-text review, and 47 studies, representing 23 & x202f;518 participants, met all inclusion criteria. Of 23 & x202f;518 participants included in the analysis, 16 839 were white (72%) and 14 387 were men (69%); median (SD) age was 29.9 (9.0) years. The overall pooled prevalence of CWS was 47% (6469 of 23 & x202f;518) (95% CI, 41%-52%), with significant heterogeneity between estimates (I-2 = 99.2%). When stratified by source, the prevalence of CWS was 17% (95% CI, 13%-21%) in population-based samples, 54% in outpatient samples (95% CI, 48%-59%), and 87% in inpatient samples (95% CI, 79%-94%), which were significantly different (P < .001). Concurrent cannabis (beta = 0.005, P < .001), tobacco (beta = 0.002, P = .02), and other substance use disorders (beta = 0.003, P = .05) were associated with a higher CWS prevalence, as was daily cannabis use (beta = 0.004, P < .001). Conclusions and Relevance These findings suggest that cannabis withdrawal syndrome appears to be prevalent among regular users of cannabis. Clinicians should be aware of the prevalence of CWS in order to counsel patients and support individuals who are reducing their use of cannabis.