Brief Online Mindfulness Program Did Not Reduce Cannabis Use in Small Randomised Trial

A pre-registered, double-blind, three-arm randomised controlled trial of 66 adults with cannabis use disorder found that a 16-day self-administered online mindfulness intervention produced no significant benefit over relaxation training or passive monitoring on any cannabis use, craving, or mindfulness outcome, though the small sample size limits the strength of these null conclusions.

Why This Matters

Cannabis use disorder affects tens of millions of people globally, yet fewer than 15 percent ever seek formal treatment, creating urgent demand for scalable, low-cost interventions that could reach underserved populations. Mindfulness-based interventions have shown promise in reducing other substance use and have a plausible mechanistic basis in disrupting automatic craving-driven behavior. Brief digital delivery formats represent one of the most practical paths to population-level impact, making rigorous tests of their efficacy a research priority. When a well-designed trial returns null findings, that result is just as scientifically important as a positive one, particularly for guiding where limited clinical and research resources should be directed next.

Clinical Summary

Mindfulness-based interventions have accumulated a credible evidence base in alcohol and nicotine cessation, with proposed mechanisms including enhanced interoceptive awareness, reduced automaticity of craving responses, and strengthened executive control over substance-seeking behavior. Building on this foundation, Solowij and colleagues (Drug and Alcohol Dependence, 2025) conducted a pre-registered, double-blind, three-arm randomised controlled trial to test whether a brief, self-administered online mindfulness program could reduce cannabis use in adults meeting criteria for cannabis use disorder. The study enrolled 66 community-recruited adults in Melbourne, Australia, randomising them equally to a mindfulness-based intervention, an active relaxation control, or passive daily monitoring over approximately 16 days.

The primary outcome was change in cannabis use days from baseline to follow-up. No significant intervention-by-time effect was found (F = 0.26, FDR-corrected p = .86), and all secondary outcomes, including cannabis quantity, craving, mindfulness scores, and relaxation, likewise showed no significant between-group differences. The authors concluded that this brief mindfulness intervention does not appear to help people with cannabis use disorder reduce their use. However, the trial enrolled only about 22 participants per arm, leaving it critically underpowered to detect small-to-moderate effects. The sample was community-recruited rather than treatment-seeking, which may have diluted motivation to change. The authors acknowledge that adequately powered trials with longer, more intensive mindfulness interventions and clinical populations are needed before definitive conclusions can be drawn.

Dr. Caplan’s Take

Patients ask me regularly whether mindfulness or meditation apps might help them cut back on cannabis. The honest answer is that the theoretical rationale is real, but we do not yet have strong clinical evidence that brief, self-directed digital programs move the needle for cannabis use disorder specifically. This trial does something valuable: it tests the hypothesis rigorously and finds no signal. But the study is small enough that a meaningful effect could easily hide in the noise, and 16 days of self-guided practice is a fraction of what most evidence-based mindfulness protocols deliver. We cannot treat this as proof that mindfulness does not work for cannabis; we can treat it as evidence that this particular dose and format did not produce detectable change.

In my practice, I do not discourage patients from incorporating mindfulness skills, but I frame it as one component of a broader strategy rather than a standalone intervention. For patients with cannabis use disorder, I prioritize structured behavioral approaches with demonstrated efficacy, ensure they have adequate clinical support, and discuss mindfulness as a skill that may enhance self-regulation over time rather than as a quick digital fix. When patients are drawn to app-based programs, I help them set realistic expectations and integrate that practice into a treatment plan with accountability built in.

Clinical Perspective

This trial sits at an early point in the research arc for digital mindfulness interventions targeting cannabis use disorder. While mindfulness-based approaches have shown efficacy for alcohol and tobacco use in larger trials with more intensive protocols, the cannabis-specific evidence remains sparse and inconsistent. This study’s null findings do not contradict the broader mindfulness literature so much as they highlight a possible dose-response threshold: a 16-day, self-administered online program may simply be insufficient to produce clinically meaningful change in a complex substance use disorder. Clinicians should not interpret these results as grounds to dismiss mindfulness-based approaches entirely, but neither should they recommend brief digital programs as effective standalone interventions for cannabis use disorder based on current evidence.

No specific pharmacological safety concerns arise from this intervention, as the mindfulness and relaxation programs studied are behaviorally based with no known adverse interaction risks. However, clinicians should be aware that patients who substitute brief self-directed programs for evidence-based treatment may experience delayed engagement with more effective care. The most actionable recommendation from this evidence is straightforward: when patients with cannabis use disorder express interest in mindfulness-based approaches, clinicians should encourage integration within a structured treatment plan that includes motivational interviewing or cognitive-behavioral therapy, rather than directing patients to brief digital programs as a primary intervention.

Study at a Glance

Study Type

Pre-registered, double-blind, three-arm randomised controlled trial with 1:1:1 allocation

Population

66 adults with cannabis use disorder (19 female), aged 18 to 56, community-recruited in Melbourne, Australia

Intervention

Brief online self-administered mindfulness-based intervention over approximately 16 days

Comparator

Active control (relaxation training) and passive control (daily cannabis use monitoring)

Primary Outcomes

Change in cannabis use days from baseline to follow-up

Sample Size

66 (approximately 22 per arm)

Journal

Drug and Alcohol Dependence

Year

2025

DOI or PMID

Pre-registration: ISRCTN76056942; OSF: osf.io/sfjwk

Funding Source

Not specified in available text

What Kind of Evidence Is This

This is a pre-registered, double-blind, three-arm randomised controlled trial with intention-to-treat analysis and false discovery rate correction, representing a high-quality design for causal inference about intervention effects. RCTs occupy the top tier of the evidence hierarchy for individual studies. However, the single most important inference constraint here is the small sample size of approximately 22 participants per arm, which renders the study substantially underpowered to detect small-to-moderate effects. Null findings from an underpowered trial cannot be confidently interpreted as evidence of no effect.

How This Fits With the Broader Literature

The broader mindfulness literature for substance use disorders presents a mixed but cautiously optimistic picture, with the strongest positive findings coming from longer, more intensive, clinician-facilitated programs targeting alcohol and nicotine use. For cannabis specifically, the evidence base is thin. Some laboratory studies have shown that even brief mindfulness inductions can modulate craving in acute settings, but translating those acute effects into sustained behavioral change through self-directed digital delivery is a different and more demanding proposition. This trial’s null result is consistent with findings from other brief intervention studies suggesting that low-intensity digital programs may not reach the therapeutic threshold needed for substance use disorders with established behavioral reinforcement patterns. It does not contradict the positive findings from more intensive mindfulness protocols such as Mindfulness-Based Relapse Prevention, but it does challenge the assumption that ultra-brief, scalable formats retain sufficient potency.

Common Misreadings

The most likely overinterpretation of this study is concluding that mindfulness does not work for cannabis use disorder. This exceeds what the evidence supports on two counts. First, the trial tested one specific brief, self-administered online format, not the full range of mindfulness-based interventions, which vary enormously in duration, intensity, and clinical guidance. Second, with only 22 participants per arm, the study had very limited statistical power. A clinically meaningful reduction in cannabis use of moderate effect size would likely go undetected in a sample this small. Equally, it would be a misreading to dismiss the null findings entirely. The study was well-designed, pre-registered, and used appropriate corrections, so the absence of even a trend toward benefit is informative, even if not definitive.

Bottom Line

This rigorously designed but underpowered trial found no evidence that a brief, self-administered online mindfulness program reduces cannabis use, craving, or mindfulness in adults with cannabis use disorder. These null findings are informative but not conclusive. They suggest that ultra-brief digital formats may be insufficient for this population, while leaving open the question of whether more intensive, clinician-supported mindfulness interventions could produce meaningful benefit. Clinicians should not recommend brief mindfulness apps as standalone treatment for cannabis use disorder based on current evidence.

References

1. Solowij N, et al. Brief online mindfulness-based intervention for cannabis use disorder: A pre-registered, double-blind, three-arm randomised controlled trial. Drug and Alcohol Dependence. 2025. Pre-registration: ISRCTN76056942; OSF pre-registration: osf.io/sfjwk.
2. Bowen S, et al. Mindfulness-based relapse prevention for substance use disorders: A pilot efficacy trial. Substance Abuse. 2009;30(4):295-305. PMID: 19904665.
3. Garland EL, et al. Mindfulness-Oriented Recovery Enhancement for chronic pain and prescription opioid misuse: Results from an early-stage randomized controlled trial. Journal of Consulting and Clinical Psychology. 2014;82(3):448-459. doi:10.1037/a0035798.