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Original Investigation
July 15, 2019

Nabiximols for the Treatment of Cannabis Dependence: A Randomized Clinical Trial

Author Affiliations
  • 1Drug and Alcohol Services, South East Sydney Local Health District, Sydney, New South Wales, Australia
  • 2Discipline Addiction Medicine, Faculty Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
  • 3Drug and Alcohol Services, Hunter New England Local Health District, Newcastle, New South Wales, Australia
  • 4Priority Research Centre for Brain and Mental Health, School of Medicine and Public Health, University of Newcastle, Newcastle, New South Wales, Australia
  • 5National Drug and Alcohol Research Centre, Faculty of Medicine, University of New South Wales, Sydney, New South Wales, Australia
  • 6Lambert Initiative Cannabinoid Therapeutics, University of Sydney, Sydney, New South Wales, Australia
  • 7School of Psychology, University of Tasmania, Hobart, Tasmania, Australia
  • 8Drug Health, Western Sydney Local Health District, Parramatta, New South Wales, Australia
  • 9National Health and Medical Research Council, Clinical Trials Centre, Faculty of Medicine and Public Health, University of Sydney, Sydney, New South Wales, Australia
  • 10National Drug and Alcohol Research Centre, University of New South Wales, Sydney, New South Wales, Australia
JAMA Intern Med. 2019;179(9):1242-1253. doi:10.1001/jamainternmed.2019.1993
Key Points

Question  Is cannabinoid agonist treatment, in combination with psychosocial services, a safe and efficacious approach to reducing illicit cannabis use in patients with cannabis dependence who are seeking treatment?

Findings  In this randomized clinical trial of 128 participants, a 12-week course of nabiximols, a combination of tetrahydrocannabinol and cannabidiol, resulted in significantly fewer days of illicit cannabis use compared with placebo, and was well tolerated by participants.

Meaning  The use of cannabinoid agonist medication appears to be a promising addition to the treatment of patients with cannabis dependence.


Importance  There are no effective medications for treating dependence on cannabis.

Objective  To examine the safety and efficacy of nabiximols in the treatment of patients with cannabis dependence.

Design, Setting, and Participants  This parallel double-blind randomized clinical trial comparing nabiximols with placebo in a 12-week, multisite outpatient study recruited participants from February 3, 2016, to June 14, 2017, at 4 outpatient specialist alcohol and drug treatment services in New South Wales, Australia. Participants had cannabis dependence (as defined by the International Statistical Classification of Diseases and Related Health Problems, Tenth Revision) and were seeking treatment, were nonresponsive to prior treatment attempts, were 18 to 64 years of age, had no other substance use disorder, had no severe medical or psychiatric conditions, were not pregnant, were not mandated by a court to undergo treatment, and provided informed consent. Results for primary efficacy measures and all secondary outcomes were obtained using a modified intention-to-treat data set.

Interventions  Participants received 12-week treatment involving weekly clinical reviews, structured counseling, and flexible medication doses—up to 32 sprays daily (tetrahydrocannabinol, 86.4 mg, and cannabidiol, 80 mg), dispensed weekly.

Main Outcomes and Measures  Primary outcome was self-reported number of days using illicit cannabis during the 12-week period. Other outcomes included alternate cannabis use parameters (periods of abstinence, withdrawal, cravings, and problems), safety parameters (adverse events and aberrant medication use), health status, other substance use, and treatment retention.

Results  A total of 128 participants (30 women and 98 men; mean [SD] age, 35.0 [10.9] years) were randomized and received at least 1 dose of study medication. Participants had used a mean (SD) of 2.3 (2.1) g of cannabis on a mean (SD) of 25.7 (4.5) days in the past 28 days. Treatment retention was comparable for the 2 groups (placebo, 30 of 67 participants [44.8%]; nabiximols, 30 of 61 participants [49.2%]), and both groups used similar mean (SD) doses (placebo, 18.5 [9.5] sprays daily; nabiximols, 17.6 [9.5] sprays daily, equivalent to a mean [SD] of 47.5 [25.7] mg of tetrahydrocannabinol and 44.0 [23.8] mg of cannabidiol). For the primary end point, the placebo group reported significantly more days using cannabis during the 12 weeks (mean [SD], 53.1 [33.0] days) than the nabiximols group (mean [SD], 35.0 [32.4] days; estimated difference, 18.6 days; 95% CI, 3.5-33.7 days; P = .02). Both groups showed comparable improvements in health status, with no substantial changes in other substance use. Medication was well tolerated with few adverse events.

Conclusions and Relevance  This study demonstrates that cannabinoid agonist treatment, in this case using nabiximols, in combination with psychosocial interventions is a safe approach for reducing cannabis use among individuals with cannabis dependence who are seeking treatment.

Trial Registration  anzctr.org.au Identifier: ACTRN12616000103460

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