Reading of the Week: Cannabis for Mental Illness (CJP)? Also, Cannabidiol for the Cannabis Use Disorder (Lancet Psych) & Love on the Police (Globe)

From the Editor

“Should I take cannabis for my mental illness?”

Our patients ask this question – in our EDs, inpatient wards, and outpatient clinics. We shouldn’t be surprised. Cannabis is now legal, and private industry pushes the medicinal benefits of cannabis. But what does the literature say?

This week, we have three selections.

The first is a new Canadian Psychiatric Association position statement that considers cannabis and mental illness. Dr. Philip G. Tibbo (of Dalhousie University) and his co-authors systematically reviewed the literature. They found 29 RCTs, including for anxiety and psychotic disorders. “Use of cannabis or a cannabinoid product should never delay (or replace) more evidence-based forms of treatment.”

marijuana-candy-sizedMany products, little evidence?

But is there emerging evidence for cannabis? Tom P. Freeman (of the University College London) and his co-authors did a phase 2a trial using CBD to address cannabis use disorder, which is written up in The Lancet Psychiatry. “In the first randomised clinical trial of cannabidiol for cannabis use disorder, cannabidiol 400 mg and 800 mg were safe and more efficacious than placebo at reducing cannabis use.”

Finally, on a pivot, in the third selection, we consider an essay from The Globe and Mail. Rebeccah Love writes about her own experiences with psychosis and her recovery. She also considers whether police should be involved in mental health crises. “The image of a police officer – often a big white man with a gun – is interpreted as a threat, an agent of death, an oppressor.”



Selection 1: “Are There Therapeutic Benefits of Cannabinoid Products in Adult Mental Illness?”

Philip G. Tibbo, Kyle A. McKee, Jeffrey H. Meyer, Candice E. Crocker, Katherine J. Aitchison, Raymond W. Lam, David N. Crockford

The Canadian Journal of Psychiatry, 11 September 2020 Online First


In response to the federal government legalizing and regulating access to cannabis in 2017, the CPA published a position statement with respect to cannabis use and adverse health consequences in youth and young adultsbased on the accumulating evidence of negative consequences of early sustained use (e.g., National Academies of Sciences and Medicine, 2017). However, psychiatrists and other mental health professionals are also being asked about the potential therapeutic uses of cannabis and cannabinoid products for mental illnesses; information is widely distributed on cannabis use being associated with mental wellness and suggesting cannabis use as a treatment for a variety of mental health concerns. As the CPA is evidence based, it is prudent to examine the existing research in this area to inform our membership needs and thus the public.

Tibbo et al. make this comment early in their position statement.

Here’s what they did:

“The CPA has systematically reviewed the existing literature on RCTs examining potential beneficial uses of cannabis and cannabinoid products to treat mental illness. This review incorporated studies in adults only (greater than 18 years old). Of the 1,982 papers identified, 29 RCTs were available to review… Methodological quality for each study was assessed using Cochrane Collaboration guidelines.”

The position statement closes with seven comments; five that are clinically relevant follow.

The CPA –

  • “Acknowledges there are no current Health Canada–approved indications for use of cannabis or cannabinoid products for the treatment of mental illness.”
  • “Acknowledges there is some limited evidence for use of cannabinoid products (excluding combustible dried cannabis and cannabis edibles) for the treatment of mental illness, but the evidence base is currently of low-quality and below that required to meet Level 1 evidence.”
  • “Strongly discourages cannabis and cannabinoid product use by anyone experiencing mental illness. Use of cannabis or a cannabinoid product should never delay (or replace) more evidence-based forms of treatment. We encourage patients to discuss potential harms of use with their treating physician.”
  • “Recommends that mental health care professionals should approach counselling around cannabinoid-based treatments with appropriate caution given the known side effects and lack of positive RCTs.”
  • “Recommends that any discussion of the potential therapeutic benefit of cannabinoid products be balanced with the risk for adverse outcomes (e.g., worsening of the underlying illness, addiction, cognitive impairment) and should be within the context of the methodology of the current RCTs, which includes carefully chosen cannabinoid products, dosing, side effect monitoring and regimented drug administration.”

A few thoughts:

  1. This is a good review of the available evidence.
  1. The recommendations are thoughtful and clear. The most clinically relevant: “Strongly discourages cannabis and cannabinoid product use by anyone experiencing mental illness.” (!)
  1. Though they drew on thousands of records from their database searches, the number of RCTs was actually not so large – just 29. The authors were able to analyze RCTs for various disorders (anxiety, PTSD, psychosis, anorexia nervosa) but the overall numbers were small (3, 1, 6, 2, respectively). The authors comment on the quality of the studies: “Sample sizes were relatively small in most of the RCTs, which weakens the conclusions, and they evaluated a variety of naturally derived and synthetic tetrahydrocannabinol (THC; e.g., nabilone, dronabinol, nabiximols) and cannabidiol products at varying doses across studies, making comparisons difficult.”
  1. Tibbo et al. have done a real service in writing this position statement. But our understanding of cannabis is limited, and that’s reflected in the current literature. In other words, as research continues, the best available evidence may be quite different in a few years.

The CPA position statement can be found here:


Selection 2: Cannabidiol for the treatment of cannabis use disorder: a phase 2a, double-blind, placebo-controlled, randomised, adaptive Bayesian trial”

Tom P. Freeman, Chandni Hindocha, Gianluca Baio, et al.

The Lancet Psychiatry, 20 July 2020 Online First


Cannabis is increasingly being legalised for medicinal and recreational use. The long-term effects of these policy reforms are unclear, but might include substantial changes to the types of cannabis products sold and their availability to millions of people worldwide. When considering the potential health effects of cannabis use, its largest contribution to the global burden of disease is the impact of cannabis use disorders, which affect an estimated 22 million people worldwide – similar to the prevalence of opioid use disorders.

So begins a paper by Freeman et al.

Here’s what they did:

  • They conducted a phase 2a, double-blind, placebo-controlled, randomised, adaptive Bayesian trial.
  • People were recruited by advertising, and needed to meet DSM-5 criteria for cannabis use disorder.
  • In the first stage: “4-week treatment with three different doses of oral cannabidiol (200 mg, 400 mg, or 800 mg) or with matched placebo during a cessation attempt by use of a double-blinded block randomisation sequence…”
  • In the second stage: “new participants were randomly assigned to placebo or doses deemed efficacious in the interim analysis.”
  • Primary end points included “reducing the urinary 11-nor-9-carboxy-δ-9-tetrahydrocannabinol (THC-COOH):creatinine ratio, increased days per week with abstinence from cannabis during treatment, or both…”

Here’s what they found:

  • In the first stage, 48 participants were involved (with 12 assigned to the three cannabidiol doses, and placebo); the 200 mg dose was eliminated from the trial as an inefficacious.
  • In the second stage, an additional 34 participants were allocated to cannabidiol 400 mg (n=12), 800 mg (n=11), and placebo (n=11); “at final analysis, cannabidiol 400 mg and 800 mg exceeded primary endpoint criteria (0·9) for both primary outcomes…”
  • “Compared with placebo, cannabidiol 400 mg decreased THC-COOH:creatinine ratio by -94·21 ng/mL… and increased abstinence from cannabis by 0.48 days per week…”
  • “Compared with placebo, cannabidiol 800 mg decreased THC-COOH:creatinine ratio by -72·02 ng/mL… and increased abstinence from cannabis by 0.27 days per week…”

A few thoughts:

  1. This is an interesting paper.
  1. The number of participants was very small.
  1. These are early days in our understanding cannabis.

The Lancet Psychiatry paper can be found here:


Selection 3: A police officer is not the best person to help someone in psychosis”

Rebeccah Love

The Globe and Mail, 21 August 2020

The Globe and Mail logo (CNW Group/The Globe and Mail)

A person with severe mental illness is considered the ultimate unreliable narrator.

She tells you a story about a horrible thing that happened to her, and you ask:

‘Yes, but did this actually happen? Are you sure you remember correctly?’ ‘Yes, but what did you do to provoke this?’ ‘Yes, but were you not a threat to other people?’ ‘Yes, but you were sick, you deserved this treatment.’

In June of 2008, I graduated as valedictorian of a well-known Toronto private school. I was ambitious, highly motivated and excited for my future.

A year later, I would be experiencing my first episode of psychosis, admitted into St. Michael’s Hospital Emergency Room. I would spend the next four years going in and out of psychiatric wards in states of serious mania and psychosis.

So begins an essay by Love.

She writes about her experiences: “The thing you have to remember about a person experiencing psychosis is that they do not interpret their surroundings in a normal way: in my episodes during these years, all things and people around me became metaphors. Police officers or paramedics or hospital security guards were not just people to me: they represented force, harm and danger.”

She also notes her privilege:

“My story is unusual: I come from a privileged white family, was able to complete my education, and was trained from a very young age to transform all my trauma and emotional energy into art. Since my last hospitalization for mania in 2012, I have gone on to a successful career as a film director, and am well-supported by my community. I currently live a mentally stable life, enjoy the company of many wonderful friends, and look forward to continuing my journey as a filmmaker and storyteller until I am a very, very old woman.”

She wonders if the experiences of others would have been different:

“The police officers I encountered in all my various hospitalizations never shot me. They never even pulled out a gun. They may occasionally pull a gun when encountering white people in crisis, but it appears from the statistics that they are much more likely to pull a gun if a person in crisis is not white. Those who do not speak English as a first language are also at a significant disadvantage. I may well have been just as sick as each of these three people I mentioned above at the times of my wellness check, but here I am today, alive, typing out an essay.”

A few thoughts:

  1. This is a great essay.
  1. How to handle mental health crises? Love is clear in her dissatisfaction with the current approach: “The best person to help a person in crisis, a person like my 18-year-old self or like Regis Korchinski-Paquet or Chantel Moore or Ejaz Choudry, is someone who has had proper training in crisis care. That could be a nurse, a social worker, or a specialized de-escalation team who can use non-violent tactics when caring for the patient. Translators are sometimes needed. Police officers are not trained properly for these kinds of emergencies, and they are not the right people to respond to these calls.”
  1. The essay doesn’t describe alternative models in detail. Others have. Writer Christie Thompson, for example, describes the work of crisis responders in Olympia, Washington:

The Globe essay can be found here:


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

1 Comment

  1. Hello,

    My name is Rebeccah Love and I wrote the Globe and Mail essay you referenced in the above post. My best friend who is a psychiatry resident pointed it out to me. Thank you for sharing my words. I could not find an email address to write to but just wanted to say that I am deeply grateful for the exposure and if ever you were seeking any further conversation about psychosis and Bipolar I would be delighted to engage. My short films revolve around Bipolar Disorder..I have invited the chief physician of CAMH to come and give a talk at my premiere and my films have screened in mental health units across Toronto through TIFF’s Outreach program, if ever you wanted to feature some short films on your blog, please let me know.

    Enjoy the week

    Rebeccah Love

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