Schizophrenia and Cannabis Use Disorder: Links Grow

What’s happening – Links between schizophrenia and cannabis use have been posited for several years. With increases in both cannabis use and in the potency of cannabis, researchers from Denmark aimed to find out whether there is also a corresponding increase in the population-attributable risk fraction (PARF) for cannabis use disorder (CUD) in schizophrenia. In other words, they wanted to understand what portion of schizophrenia could have roots in CUD.

The team, led by Carsten Hjorthoj, PhD, analyzed several decades of data from Denmark’s nationwide registry. They discovered that in 1995, the PARF was about 2%. In 2010 and beyond, it increased to 6%–8%, demonstrating a link between the number of people using cannabis and the number of people who go on to develop schizophrenia. While this finding is not unexpected, the implications are significant and should be considered when state and federal governments are deciding on cannabis legalization policies.

Why it’s complicated ­– Many individuals with mental health disorders self-medicate with cannabis. Clinicians can play an important role in educating patients about the risks of both CUD and its potential link to schizophrenia while also screening patients regularly for these comorbidities.

Reports and Perspectives

  • An editorial in JAMA recognizes the importance of the study by Hjorthoj et al in calling attention to the complications of increasing cannabis use and schizophrenia.
  • An article in US News exploring the link between cannabis, mental illness, and driving, stresses that there are more people who can handle cannabis use well than those who have difficulty managing use.
  • A 2020 Cureus review examines whether cannabis is causative or curative in schizophrenia, concluding that more research is needed.
  • The Child Mind Institute points out that adolescents can be particularly vulnerable to the negative effects of marijuana use, including developing schizophrenia, while young people with a predisposition to mental illness may also be drawn to use cannabis.
  • @WFSBP_Congress (World Congress of Biological Psychology) tweets: “The medicinal use of #cannabis can be good for some cases of #childhoodepilepsy, however, as the potency of cannabis continues to rise, the risks are becoming more evident. Professor Sir Robin Murray will be discussing the link between cannabis and #psychosus at the #WFSBP2021.”
  • @help4psychosis (early Psychosis Intervention Ontario Network) says: ”There is considerable evidence linking #cannabis and #psychosis. Teenage cannabis use can induce psychosis immediately, or years later. Full recovery from psychosis is possible, but the outlook is more hopeful when cannabis use stops…”
  • @GrahamCLDavey (mental health researcher) shares: “’Childhood trauma and regular cannabis use independently predicted illness vulnerability as did an interaction.’ The relative and interactive impact of multiple risk factors in schizophrenia spectrum disorder …”

In Practice

Treatment-Resistant Depression: Is Deep TMS the Answer?

What’s happening – For people with treatment-resistant depression (TRD), transcranial magnetic stimulation (TMS) may provide hope when other modalities fail. TMS helps to activate (or quiet) nerve cells in an effort to reverse the effects of depression – but not all forms of TMS are created equal. In addition to traditional TMS, which uses a figure-8 shaped coil with shallow reach, deep TMS provides a more intense form of treatment using an H-shaped coil inside a helmet that penetrates about 4.5 times more deeply.

A recent pilot study (n=28) measured the effectiveness of performing two daily deep TMS sessions over both a 10-day period and a 15-day day period in patients with major depressive disorder (MDD). The findings, which recently appeared in European Archives of Psychiatry and Clinical Neuroscience, revealed that 38% of individuals with TRD who underwent 10 days of deep TMS experienced relief from their depression symptoms, and 42% of those receiving the 15-day treatment course also had their symptoms resolved.

Why it’s complicated – TMS does not affect everyone in the exact same way, which has led researchers to suggest that the procedure (both TMS and deep TMS) be tailored to respond to each individual’s diagnosis and needs (such as where the device is placed and how), rather than using a one-size-fits-all approach. See our Psy-Q below on patient identification for TMS.

Reports and Perspectives

  • A registry study of 103 practice sites shows that TMS can be very effective in people with major depression when compared to alternative interventions for TRD and suggest TMS as a first-line treatment for MDD.
  • A Brain Stimulation paper evaluates the effectiveness of TMS and deep TMS for MDD; a similar trial was published in the Journal of Psychiatric Research.
  • @olympatms (psychiatrist trained in TMS) says: “So it is plausible that because TMS is an effective therapy for major depression, it might be equally successful in cognitive improvement…”

In Practice

Psy-Q Challenge

Who might be a good candidate for transcranial magnetic stimulation (TMS)? Eric Patterson, LPC, answers.

Get the Answer

Kratom Ban: Dangers and Benefits Continue to be Debated

What’s happening – Kratom, a natural herb found in Southeast Asia, has received attention for its medicinal properties over many decades. When consumed at low doses, it’s believed to have stimulant qualities, while higher doses can act as a sedative. Kratom brings about an opioid-like response, leading some people to rely on it to manage pain (and often in lieu of opioids). While some informal studies reveal potential benefits of kratom as an antidepressant and anxiolytic, no formal studies have been conducted to measure the effectiveness.

A new case report by Alessandro E. Vento et al published in the Yale Journal of Biology and Medicine calls attention to the urgent need for more research to help the medical community better understand the mechanisms through which kratom works as an antidepressant and antipsychotic.

Why it’s complicated – Kratom is not currently regulated in the US and its full risks are unknown. The FDA has seized kratom sold as dietary supplements and is currently seeking a possible global kratom ban due to the substance’s growth as a drug of misuse and abuse. The agency attempted to ban kratom domestically in the US but failed. Scientific American responded in its editorial against a ban.

Reports and Perspectives

  • A case report in Frontiers in Psychiatry examines the effects of long-term kratom use (kratom use disorder) and withdrawal effects, including how to treat the addiction; the team found that anxiety, mood changes, and difficulty eating and sleeping may actually worsen, resembling opioid use disorder (OUD) and withdrawal.
  • Harvard Health Blog explores the risks and benefits of kratom use and talks about the need to better understand the potential of this substance.
  • The Cleveland Clinic shares a Q&A on the risks of using kratom and educates readers on why this “natural” substance may not be safe to take.
  • The Child Mind Institute warns that despite the fact that kratom is legal, it can also be addictive and poses real danger among teens.
  • @TheKratomAssn (organization formed by kratom consumers) says: “The AKA is still collecting comments to submit to the UN and WHO, and we’re optimistic our suit against the FDA will reopen the federal registry portal for submissions…”
  • @NYHarmReduction (organization fighting for harm reduction) says: “The Biden administration’s decision of whether to ban kratom will provide if they are actually taking a #harmreduction approach to drug policy—or if it’s simply lip service while they continue the shameful legacy of the #WarOnDrugs.”

In Practice

  • The US DEA provides a Fact Sheet on kratom
Last Updated: Sep 2, 2021