From the Editor

It’s popular – but is it actually helpful?

With legalization, cannabis is readily available. Not surprisingly, our patients are increasingly trying it. But what’s the latest evidence? In the first selection, we consider a new paper that was just published by The American Journal of Psychiatry. Dr. Kevin P. Hill (of Harvard University) and his co-authors review almost 850 papers and comment on everything from the potential therapeutic effects of cannabis to clinician guidance. “There is little data indicating that cannabinoids are helpful in treating psychiatric illness, while there is considerable evidence that there is potential for harm in vulnerable populations such as adolescents and those with psychotic disorders.” We consider the big paper and its clinical implications.


In this week’s second selection, we mull physicians and burnout. Dr. Jillian Horton (of the University of Manitoba) joins me for a Quick Takes podcast interview. We discuss burnout, mindfulness, and recovery. She comments on her own burnout: “I would get home at the end of my long shifts on the wards, and I would have nothing left. Nothing left for myself, nothing left for my spouse, nothing left for my children.”

Please note that there will be no Readings for the next two weeks. We will return in early January with the best of 2021.


Selection 1: “Risks and Benefits of Cannabis and Cannabinoids in Psychiatry”

Kevin P. Hill, Mark S. Gold, Charles B. Nemeroff, et al.

The American Journal of Psychiatry, 8 December 2021  Online First


The United States is in the midst of a period of rapid change in cannabis policy. Current state laws range from those where cannabis has been legalized for both medical and recreational purposes to those where cannabis products remain illegal. In between those extremes are states where cannabis has been decriminalized or is available solely for medical use (with or without decriminalization)…

The widespread accessibility and increasing recreational use of cannabis in recent decades has promulgated the notion that cannabis products are overwhelmingly benign. An estimated 43.5 million Americans age 12 years or older used cannabis in 2018. Approximately 10% of cannabis users report cannabis consumption to treat specific medical disorders or symptoms, including stress management and relaxation, treatment of mood and anxiety symptoms, and pain, nausea, and vomiting.

Cannabis is touted as a treatment for myriad medical conditions. However… it remains understudied, underregulated, and surrounded by controversy…There are many competing interests that create pressure for increasing the availability of medicalized or legalized cannabis. For example, patients desperate for relief of psychiatric symptoms may be motivated to seek relief via cannabis even in the absence of formal evidence of efficacy. Similarly, individuals who enjoy recreational cannabis or who have cannabis use disorder may wish to have their cannabis use sanctioned by the medical establishment…

So begins a paper by Hill et al.

Here’s what they did:

  • “Searches of PubMed and PsycInfo were conducted for articles published through July 2021 reporting on ‘cannabis’ or ‘cannabinoids’ or ‘medicinal cannabis.’
  • “Additional articles were identified from the reference lists of published reviews.”

Here’s what they found:

“A total of 4,431 articles were screened, and 841 articles that met criteria for inclusion were reviewed by two or more authors.”

Highlights from the review:

Acute Effects

“Acute cannabis use is associated with impaired learning, memory, attention, and motor coordination. These acute effects are often related to route of ingestion. The wide-ranging effects of cannabis can be attributed in part to the presence of CB1 receptors in the prefrontal cortex, globus pallidus, substantia nigra, hippocampus, striatum, and cerebellum. Acute cannabis use can also affect executive functioning, including the ability to plan, organize, solve problems, and make decisions. This may potentially result in users making risky decisions that they would not otherwise make. Cannabis intoxication can be associated with marked feelings of anxiety and paranoia as well as possible cannabis-induced psychosis.”

Chronic Effects

“Several studies have described the adverse effects of regular cannabis use on the frontal lobe and executive function. These effects are more pronounced in young regular cannabis users. For example, Gruber et al. showed that those who begin using cannabis regularly before age 16 had deficits on standard neurocognitive tests. A longitudinal study of 799 adolescents revealed a dose-dependent association between cannabis use from baseline to 5-year follow-up and neurodevelopmental abnormalities, including accelerated cortical thinning, primarily in prefrontal regions of the brain…”

Indirect Effects

“Secondhand cannabis smoke produces the same cannabis-related changes in brain and behavior as first-hand exposure. For example, cannabis withdrawal syndrome can occur in patients with exposure to cannabis smoke following administration of cannabinoid antagonists. Cannabis use by a pregnant woman is also associated with indirect effects on the fetus; for example, a recent study of perinatal outcomes showed that the crude rate of preterm birth was 12.0% among cannabis users, compared with 6.1% among nonusers (risk difference=5.88%…). Additionally, cannabis smoking may make cigarette smoking more likely.”

Potential Therapeutic Uses

“Beyond the FDA-approved indications for cannabinoids, the best evidence for the medical use of cannabinoids is in chronic pain (including neuropathic pain) and muscle spasticity associated with multiple sclerosis, for which multiple randomized controlled trials and systematic reviews support their efficacy. The National Academies Committee on the Health Effects of Marijuana concluded that there is ‘conclusive or substantial evidence’ that cannabis is effective for the treatment of chronic pain in adults… An earlier meta-analysis of 28 such studies by Whiting et al. determined that there was ‘moderate-quality evidence’ and found that the published data supported the use of cannabinoids in the treatment of chronic pain… Other reviews, however, describe the evidence for cannabinoids in chronic pain as weaker.”

Cannabinoids for the Treatment of Substance Use Disorders

“Multiple cannabinoids have been studied as potential treatments for cannabis use disorder, a syndrome for which there is currently no FDA-approved pharmacotherapy. In a 12-week cannabis use disorder trial, dronabinol led to significantly better treatment retention and less withdrawal symptoms than placebo, but it did not separate from placebo on the primary outcome measure: a 2-week abstinence from cannabis. Nabilone appears to be safe and well tolerated in patients with cannabis use disorder, but its efficacy for the disorder has yet to be evaluated in adequately powered trials…

“The evidence supporting the use of cannabinoids as pharmacotherapy for other substance use disorders is mixed. Some patients report that cannabis use has helped limit their use of opioids or alcohol. While data from randomized controlled trials evaluating cannabinoids as pharmacotherapy for substance use disorders is lacking, 400 mg or 800 mg of CBD once daily for 3 days was found to significantly reduce craving, anxiety, and physiological responses associated with drug cues in patient with opioid use disorder… By contrast, cannabis use has been associated with a significantly lower percentage of days abstinent from alcohol in patients with alcohol use disorder.”

Cannabinoids for the Treatment of Psychiatric Disorders

“A recent systematic review and meta-analysis by Black et al. evaluated 83 studies of cannabinoids for symptoms of mental disorders, including anxiety, depression, posttraumatic stress disorder (PTSD), psychosis, ADHD, and Tourette’s syndrome. The available evidence base was limited by lack of high-quality randomized controlled trials, small sample sizes, and lack of standardization across trials. However, the authors found limited efficacy of cannabinoids in treating anxiety disorders in patients with co-occurring medical conditions. They did not find evidence supporting cannabinoid pharmacotherapy for the other psychiatric indications they assessed.”


“CBD is sold over the counter in a variety of formulations for psychiatric and medical purposes, and it is estimated that up to 14% of Americans used CBD in the past year. Unlike cannabis, CBD use does not produce the psychoactive ‘high’ experience that characterizes cannabinoids containing THC. And, when present in combination with THC, CBD may mitigate the potentially harmful effects of THC… Most CBD is obtained without a prescription, in products that are unregulated with regard to purity, potency, and accuracy of labeling. As with other over-the-counter supplements, patients may receive flawed or incomplete education about CBD. Few randomized controlled trials have systematically investigated the feasibility, safety, and efficacy of CBD in psychiatric patients. Randomized controlled trials examining the effectiveness of CBD in psychosis have produced mixed results. One trial showed that 800 mg/day of CBD for 4 weeks was as effective as amisulpride in treating both positive and negative symptoms of schizophrenia and had fewer associated side effects.”

Guidance for Clinicians

“The level of evidence supporting cannabinoids for treating anxiety is low, despite the anecdotal reports describing its efficacy. When patients report that cannabinoids provide subjective relief of anxiety, psychiatric clinicians have an opportunity to provide education about the current state of the evidence. Since the number needed to harm is likely to be much lower for THC-containing compounds than those with pure CBD, clinicians whose anxious patients are reporting benefits from THC may consider recommending a monitored trial of CBD instead.

“In general, however, prescribing clinicians should avoid initiating or recommending cannabinoid pharmacotherapy for most psychiatric patients. There are no clinical trials that support the use of cannabinoids as pharmacotherapy for mood disorders, and there is limited evidence supporting their use in PTSD. Converging lines of evidence suggest that THC-containing compounds are likely to cause harm in patients with existing psychosis or at high risk for psychosis.”

A few thoughts:

  1. This is an excellent review.
  1. The paper is very relevant to practice.
  1. There is much to like here – a highly readable review, tapping the latest in the literature, and published in a major journal.
  1. They make an important observation on how cannabis itself has changed: “Widely held assumptions about the safety of today’s cannabinoids may arise from past decades of experience with cannabis products, such as cannabis from the 1970s with 3% – 4% THC, that are far less relevant today.”
  1. Dr. Hill and his co-authors find very limited evidence for the use of cannabis for mental disorders. Though some time has passed since publication, the Canadian Psychiatric Association’s position – that “strongly discourages cannabis and cannabinoid product use by anyone experiencing mental illness” – continues to be relevant. The CPA position statement was considered in a past Reading:
  1. The literature is evolving. The authors note our role: “Psychiatric clinicians should be educated and prepared for sensible, evidence-based discussions with their patients. The ability to summarize the published data and relevant science is especially important given the polarizing nature of the cannabis debate.”

The full AJP paper can be found here:

Selection 2: “Burnout & Recovery: A Conversation with Dr. Jillian Horton

Jillian Horton

Quick Takes, December 2021


In this episode of Quick Takes, I speak with Dr. Jillian Horton, a practicing internist. Dr. Horton has just written an autobiographical book and serves as the Associate Chair of the Department of Internal Medicine at the University of Manitoba’s Faculty of Medicine. She speaks knowledgeably – and personally.

I highlight from the discussion:

On burnout

We know what the literature tells us; we think of this trifecta: depersonalisation, emotional exhaustion, and a low feeling of personal accomplishment.

So that’s what the books tell us to expect when we’re burnt out. But when I look back at my own life and how I think burnout has manifested, it’s often been much more subtle.

On medical training

We’re taught to disembody. We are taught to work through our fatigue, our hunger, our intense emotions. We’re not really taught to be mindful about those things and learn to coexist with them. We’re taught to ignore them, to bury them deep.

On mindfulness and her doubts

I had fundamentally misunderstood what mindfulness is. I always thought that mindfulness was part of an agenda to brainwash me – to turn me into sort of a Pollyanna and to make me somehow say, “oh, my suffering doesn’t matter.” Everyone’s suffering is important, and I resented that.

On systems

We can look at the Stanford Model of Professional Fulfilment – a wonderful way for all of us to think about what we would like it to feel like to work in the systems where we train and go on to spend most of our lives.

And that model has three components.

One is the culture of wellness; that is, how we treat each other, whether we have psychological safety, our leaders, whether our leaders lead us with compassion, know us care about us. And the quality of leadership that we work for.

Two, efficiency of practice; that is, the added cognitive load, all the multiple EMR platforms that we have to work on, the things that drive us all around the bend in our clinical environments, the things that we have to do over and over that seem futile, pointless, that are misaligned with our expertise.

And then finally the personal resilience piece. So how do we work with our own reactivity? How do we emotionally self-regulate? What have we done to cultivate our resilience? What kind of safety net do we have? What choices do we make to care for our health, physical and mental, when we have the ability to make those choices and exert some control?

On the subject of her next book

Probably mindfulness. Probably a series of essays about how we incorporate that work into our daily life – but with my usual sarcastic and occasionally expletive laden voice.


The above answers have been edited for length.

The podcast can be found here, and is just over 22 minutes long:

Reading of the Week. Every week I pick articles and papers from the world of Psychiatry.