Cannabis for Anxiety and Mood Disorders

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Visual Abstract

Summary

Cannabis for Anxiety and Mood Disorders: Living Systematic Review

Background
  • Anxiety and mood disorders (depressive disorders, and bipolar disorder) are common in the US.
  • People with anxiety and mood disorders may use cannabis for many reasons, yet its efficacy and safety for these conditions is unknown.
  • This review aims to examine the evidence on the effectiveness of cannabis for the treatment of anxiety, depression, and bipolar disorders.
Methods

Living systematic review

Search:

  • Ovid MEDLINE ALL
  • PsycINFO
  • Scopus
  • CENTRAL
  • Pubmed
  • ClinialTrials.gov
  • ScanMedicine
  • DuckDuckGo and Google Scholar
  • Core journals

Screening: Studies (controlled clinical trials and observational studies with comparison groups) assessed the effects of plant-based cannabis preparations; whole-plant extracts (e.g., nabiximols); or US Food and Drug Administration (FDA)-approved synthesized, pharmaceutically prepared cannabinoids (e.g., dronabinol, nabilone) in adults with a diagnosis of anxiety or mood disorder.

Risk of Bias (RoB): Tool adapted from those used by national organizations, including SIGN, NICE and the National Heart‚ Lung‚ and Blood Institute

GRADE: Overall certainty of evidence (CoE) for each outcome was determined using the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach

Updates: Search to be updated at regular intervals

Findings
  • 11 eligible studies
  • Studies found it is uncertain whether cannabis affects symptoms in adults with anxiety or mood disorders.
  • Anxiety disorders (3 studies)
    • Mixed findings with very low certainty. Unable to determine if cannabis is safe or effective for anxiety symptoms.
  • Depressive disorder (1 study)
    • Very low certainty evidence – unable to determine association with cannabis use and depression symptoms, QoL or functioning, or healthcare utilization.
  • Bipolar disorder (7 studies)
    • Low certainty from nonrandomized studies that cannabis use may be associated with increased risk of mania and other bipolar-related symptoms, as well as poorer disease outcomes, such as recovery and remission.

Summary of Findings (GRADE)

Outcome
Number of Studies
Sample Size

CoE Relationship Rationale for CoE Rating
Anxiety disorders

Symptom control

2 RCTs and 1 CCT

N = 140

●◌◌◌

Very low

Mixed results for the use of CBD and nabilone on anxiety, depression, other anxiety-related symptoms Downgraded 1 level each for RoB, imprecision (i.e., small sample sizes), inconsistency (i.e., mixed results), and indirectness (i.e., limited populations and cannabis formulations)
Quality of life and functioning Not reported
Health care utilization Not reported

Safety

1 RCT and 1 CCT

N = 100

●●◌◌

Low

No strong association between the use of CBD or nabilone and AEs Downgraded 1 level each for imprecision (i.e., small sample sizes or not assessable) and indirectness (i.e., limited populations and cannabis formulations)
Depressive disorders

Symptom control

1 NRS

N = 2,577

●◌◌◌

Very low

No association between cannabis use and remission from MDD

Higher levels of cannabis use (i.e., CUD) were associated with significantly higher levels of depression

Downgraded 1 level for indirectness (i.e., nonrandomized study with a population using cannabis, but not clear if using for depression specifically)a

Quality of life and functioning

1 NRS

N = 2,577

●◌◌◌

Very low

No associations between cannabis use and suicidality, functionality, and quality of life in people with MDD Downgraded 1 level for indirectness (i.e., nonrandomized study with a population using cannabis, but not clear if using for depression specifically)a

Health care utilization

1 NRS

N = 2,577

●◌◌◌

Very low

No association between cannabis use and health care utilization Downgraded 1 level for indirectness (i.e., nonrandomized study with a population using cannabis, but not clear if using for depression specifically)a
Safety Not reported
Bipolar disorders

Symptom control

7 NRS

N = 4,118

●●◌◌

Low

Use of cannabis may be associated with increased levels of mania and recurrent and lower rates of recovery and remission Not downgraded; even though people may not be using cannabis specifically for bipolar disorder, the findings are consistent across the included studies so we did not downgrade for indirectness in this instance

Quality of life and functioning

1 NRS

N = 3,459

●◌◌◌

Very low

Cannabis use was associated with less satisfaction with life and a lower probability of having a relationship compared with no cannabis use

Cannabis use was also associated with greater work impairment and being more likely to live apart from a partner

Downgraded 1 level each for RoB for indirectness (i.e., nonrandomized study with a population using cannabis, but not clear if using for bipolar disorder specifically)a

Health care utilization

1 NRS

N = 144

●◌◌◌

Very low

People with bipolar disorder and CUD were more likely to be prescribed conventional antipsychotics than people with bipolar disorder without CUD Downgraded 1 level each for RoB and for indirectness (i.e., nonrandomized study with a population using cannabis, but not clear if using for bipolar disorder specifically)a
Safety Not reported

Note. a Inconsistency not assessed; single study only.
Abbreviations. AE: adverse event; CBD: cannabidiol; CCT: controlled clinical trial; CoE: certainty of evidence; CUD: cannabis use disorder; GRADE: Grading of Recommendations, Assessment, Development, and Evaluations approach; MDD: major depressive disorder; NRS: nonrandomized study; RCT: randomized control trial; RoB: risk of bias.

Conclusions
  • The evidence for cannabis and anxiety and mood disorder-related outcomes is uncertain.
  • More research is urgently needed to address increasing interest in cannabis use for mental health disorders.
Gaps in Evidence
  • No evidence on quality of life or functioning for cannabis and anxiety disorders, nor for safety of cannabis for depressive and bipolar disorders.
  • High quality, randomized studies of cannabinoids are needed to determine whether cannabis has any effects on anxiety or mood disorders.
  • We identified 5 ongoing, phase 3 or 4 RCTs of cannabis in anxiety, depression, or other mood disorders expected to be completed in the coming years.

Suggested citation: Shaw B, Robalino S, Ayers C, Ward R, Yeddala S, Morasco B, Kansagara D. Cannabis for anxiety and mood disorders. The Systematically Testing the Evidence on Marijuana Project; 2024. Accessed (Month DD, YYYY). https://www.cannabisevidence.org/evidence-syntheses/anxiety_and_mood_disorders/

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Page Last Reviewed:  February 2024