Identifying and addressing cannabis withdrawal syndrome

Introduction

Cannabis withdrawal syndrome (CWS) is a clinically recognized condition in the DSM-5 that can occur after cessation of regular or heavy cannabis use. Although not life-threatening, its symptoms can be distressing and affect individuals’ mental and physical well-being, potentially leading to relapse or repatriation in a military context. CWS is particularly relevant as cannabis use has become more common after its legalization in Canada. Awareness along with identification of CWS is helpful for military clinicians treating patients with cannabis use disorder and those attempting to reduce or discontinue use, specifically if a deployment, change in trade, or usage and access is to become an issue.

The College of Family Physicians of Canada (CFPC) continues to reaffirm that medical cannabis has very limited indications, such as in treatment-resistant neuropathic pain, palliative or end-of-life pain, chemotherapy-induced nausea and vomiting, and spasticity in multiple sclerosis when conventional therapies fail — and emphasizes that any authorization should be approached with caution and accompanied by harm reduction discussions.^10,11 Despite occasional prescribing for certain pain and mental health symptoms, most cannabis use in Canada occurs without medical authorization, reflecting recreational and self-medicating use.¹³ In fact, a 2024 report found that approxi-mately 74% of Canadians using cannabis for medical reasons did so without a health care provider’s authorization.¹²

1. How common is CWS?

Nearly half of regular cannabis users experience withdrawal symptoms. Regular use definitions are a challenge to clinically state due to different patterns of use and different formulations of commercially available cannabi-noids. In addition to commercially available products, illegal procurement is still a possibility making regular use definitions more of a challenge. High-quality evidence of CWS in the Canadian military population is lacking.

A meta-analysis found that the prevalence of CWS is approximately 47% in regular or dependent users. This rate increases in clinical settings, with inpatient users showing rates as high as 87%. Daily use and concurrent substance use disorders elevate the risk.¹

Patients living with PTSD are significantly more likely to use cannabis, often as a form of self-medication when conventional treatments fall short. For example, one Canadian study found that individuals with PTSD were twice as likely to use cannabis compared to those without PTSD (28.2% vs. 11.2%, respectively), highlighting the prevalence of self-medication behaviour in this population.^16,17

2. What are the typical symptoms and timeline?

Symptoms begin quickly and peak within the first week after last use. CWS symptoms typically emerge within 24–48 hours of cessation, peak around days 2–6 and resolve within 1–2 weeks. DSM-5 symptoms include: ir-ritability/anger, anxiety, sleep disturbance (e.g., insomnia, vivid dreams), appetite or weight loss, restlessness, depressed mood, physical symptoms (e.g., headaches, nausea, sweating).² Usage of a cannabis misuse screening tool such as the Cannabis Use Disorders Identification Test-Revised (CUDIT-R)⁶ can help in early identifica-tion of those at possible risk. In addition to a screening tool, questions about type/potency of marijuana, quan-tity, and ingestion route should be asked and documented.

3. Does comorbid psychiatric illness influence CWS severity?

Patients with psychiatric comorbidities can have prolonged withdrawal symptoms as mentioned above. Young adults with known psychiatric diagnoses reported delayed symptom resolution compared to those without (n = 50). Improvement typically occurs by the second week for these individuals.³ In a large U.S. study, 12.1% of frequent cannabis users met criteria for CWS. Those with CWS had higher rates of mood, anxiety, and person-ality disorders, and experienced greater disability. The most common symptoms included anxiety, hostility, sleep difficulties, and depression.⁴ Cannabis withdrawal severity and symptoms do not differ by sex or gender, but are instead linked to frequency and duration of use.⁸

It should be noted that cannabis is currently not recommended for the treatment of major depressive disorder, as out-lined in the most recent Canadian Network for Mood and Anxiety Treatments (CANMAT) guidelines.9 The most recent 2023 update emphasized the lack of evidence supporting cannabis use in depression, and that clinicians should rely on established first-line pharmacological and psychological therapies.⁹

4. Can withdrawal trigger psychosis?

Cannabis withdrawal may precipitate acute psychotic episodes. Case reports and registry data illustrate that some individuals experience first-episode or relapsing psychosis during cannabis withdrawal. Daily users who abruptly stop are most at risk, and continued cannabis use increases relapse likelihood.² Some factors for more severe withdrawal could include younger age, co-existing mental health issues, longer duration of cannabis use, higher daily dose, inhaled (smoked) vs. ingested cannabis. It is notable that 59% of chronic pain patients using medical cannabis reported moderate to severe CWS.²

In addition to psychosis, clinicians should be vigilant for CWS, as its symptoms — including anxiety, depres-sion, irritability, and sleep disturbance — often overlap with psychiatric disorders and may be misinterpreted as a relapse or exacerbation of mental illness.^14,15 With an absence of awareness about CWS, both patients and clinicians may inadvertently perceive cannabis as therapeutically beneficial, when in fact resuming use may sim-ply relieve withdrawal symptoms rather than treating the underlying disorder which may be unmasked when the cannabis use is truncated. Therefore, any clinicians advising cessation as a recommendation should educate patients about CWS to prevent misdiagnosis and improve outcomes.

5. Are there treatments for CWS in Canada?

No medications are currently approved specifically for CWS in Canada. Some pharmacological treatments such as dronabinol (synthetic THC analog, not available in Canada) and gabapentin have been utilized in reducing symptoms⁵ but there is no clear evidence clinically for their use and they are not approved in Canada. Psychoso-cial interventions such as CBT are likely to remain the mainstay of treatment.⁶

A systematic review identified 44 cases from published reports and 68 additional cases from electronic health records where acute psychosis followed abrupt cannabis cessation. Most individuals were daily users, and relapse rates were significantly higher among those who resumed cannabis use. This highlights a need for careful moni-toring during cessation, particularly in heavy users.

6. Identifying Cannabis Use Disorder in Canada.

The CUDIT-R is a validated screening tool designed to detect problematic cannabis use and potential cannabis use disorder in clinical and community settings.⁷ It was an iterative improvement upon the original CUDIT, and offers a brief and practical method of identifying risky patterns of cannabis use among individuals, including those who may not yet meet full diagnostic criteria. Within a military population, where cannabis use may impact op-erational readiness, deployment eligibility, and overall performance, the CUDIT-R provides a mechanism for early identification of misuse by CAF clinicians. Its application would allow military clinicians to intervene appropri-ately and possibly early, guiding members toward treatment or support before cannabis misuse becomes a barrier to effective service.

Conclusion

CWS is a clinical issue to be aware of for military physicians, especially among daily users, heavy users, and individuals with psychiatric comorbidities both in garrison but also in a possible deployed environment. Con-sideration of this clinical entity during the pre-deployment phase of medical screening at least four weeks prior to deployment would allow the minimum time to likely address this clinical entity. Recognition and treatment of CWS could improve patient outcomes and reduce the likelihood of relapse and operational risk. Clinicians should consider screening for CWS in relevant military populations and provide appropriate psychosocial sup-port (CBT) as pharmacological options are limited.

Biography

Paul Dhillon, CCFP(EM), is a family physician with added certification in emergency medicine and holds qualifications in dive medicine, as a flight surgeon, and in submarine medicine. He is a medical officer at 11/12 (Vancouver) Field Ambulance in Vancouver, British Columbia, Canada, and currently serves as Brigade Surgeon for 39 Canadian Brigade Group.

Funding Statement

No funding was received for this article.