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The Latest in Cannabis Research: Spring 2018

Published on March 22, 2018 · Last updated July 28, 2020

In the first quarter of 2018, we’ve seen advances in our understanding of cannabis’ therapeutic benefits in a range of disorders, diseases, and cancers. Below are just some of the biggest cannabis research headlines we’ve seen over the last few months. The list is by no means exhaustive and only represents peer-reviewed research articles, but stay tuned for more emerging research this summer.

Studies at a Glance:

Cannabis Is Safe and Effective at Treating Pain in the Elderly

Published: February 2, 2018

The elderly (+65 years of age) represent a rapidly growing cohort of medical cannabis consumers, so a better understanding of cannabis’ efficacy and safety in these patients is needed. To address this, a recent survey was conducted in over 900 elderly Israeli patients who used medicinal cannabis for at least six months.

Regardless of strain preference, 93.7% of patients reported that cannabis improved their symptoms after six months of use.

In this study, 75% of the patients had no prior history with cannabis consumption, making this a powerful assessment of the onboarding experience in the elderly. Most patients began using cannabis for pain-related conditions including cancer pain, but a smaller number of patients were using it to treat chemo-related nausea, Parkinson’s disease, post-traumatic stress disorder, and Crohn’s disease. While THC-forward strains were the most consumed, CBD-rich strains were especially common in patients suffering from pain, chemotherapy side effects, Parkinson’s disease, and inflammatory diseases.

Regardless of strain preference, 93.7% of patients reported that cannabis improved their symptoms after six months of use. It was particularly helpful in reducing pain, on average reducing pain from an 8 (on a scale to 10) to a 4. This reduction in pain led 15% to entirely stop their opioid pain medications.

Overall, cannabis use improved quality-of-life from “bad” to “good” with few adverse side effects. The most common side-effects, dizziness and dry mouth, were reported in only 10% and 7% of patients, respectively. Two percent or less reported confusion, disorientation, or weakness.

Together, these findings strongly support the safety and efficacy of medicinal cannabis in an elderly population for treatment of pain-related conditions.

CBD Protects Against the Damaging Effects of Iron in Aging Brain Diseases

Published: March 5, 2018

Throughout your life, you build up mineral levels in your body and brain. Excessively high levels of certain minerals can cause health problems. For instance, the accumulation of iron in certain brain regions is thought to contribute to aging diseases like Alzheimer’s and Parkinson’s disease.

Protecting against the damaging effects of iron overload could be a novel approach to protecting the brain from neurodegenerative aging diseases.

Iron overload can impair the function of the cell’s primary energy producers, the mitochondria, and disrupt their DNA. This impairs brain cell function. It can also lead to an overload of free radicals which increases brain inflammation and causes further damage. Protecting against the damaging effects of iron overload could be a novel approach to protecting the brain from neurodegenerative aging diseases.

A study published in Brain Research Bulletin found that CBD protected against the damaging effects of iron overload on mitochondrial function in rats. CBD didn’t get rid of the excess iron, but instead, enabled the mitochondria to better handle the iron so that it was less disruptive. CBD also prevented iron’s damaging effects on the mitochondrial DNA.

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While CBD’s protective mechanism was not directly assessed, it was proposed that CBD’s potent anti-oxidant and anti-inflammatory qualities could help protect against the damage to the mitochondria and their DNA. The results from this study support the use of CBD as a preventative tool in aging brain diseases.

This idea that CBD may be prophylactic is gaining increasing support. CBD has also been found to protect against brain damage caused by cardiovascular events, brain injury, and alcohol damage.

A Case for Balanced THC and CBD in Colorectal Cancer Prevention

Published: January 1, 2018

Many people consume cannabis for treatment of cancer-related symptoms, like pain and nausea. However, there’s building evidence from laboratory studies that certain cannabinoids may have anti-cancer effects.

A study by Austrian scientists determined that CB1 receptor activation has tumor-suppressing effects in colon cancer, while GPR55 receptor activation has tumor-promoting effects. CB1 receptors are a primary target of the high-inducing cannabinoid, THC. By activating CB1 receptors, THC could have tumor-suppressing effects. GPR55 is a more recently identified target of CBD. CBD has been shown to block the activity of GPR55 receptors, and therefore, could protect against colorectal cancer by blocking GPR55 activity and suppressing tumor growth.

Together, these findings suggest that a combination of THC and CBD may protect against colon cancer by activating the tumor-suppressing CB1 receptors and blocking the tumor-promoting GPR55 receptors. An additional benefit is that CBD protects against the development of tolerance to THC’s effects on CB1 receptors, which is the weakening of its effects over time. Therefore, a combination of THC and CBD could hypothetically prevent colorectal cancer and protect against tolerance to the treatment. However, this study only supports the mechanistic theory behind the benefits of THC and CBD in colorectal cancer. Further studies are still needed to be conducted in humans before this becomes a clinical treatment strategy.

Can Cannabis Cure Cancer?

CBD Protects Against Endometrial Cancer by Activating TRPV1 Receptors

Published: February 13, 2018

In another cancer-related study, scientists working in Portugal investigated the effects of THC and CBD on endometrial cancer (i.e., cancer of the uterus).

CBD caused many of these cancerous cells to die by activating TRPV1 receptors.

Endometrial cancer can result from consistently high estrogen levels, either due to genetics or supplementation during menopause. To model this risk, scientists used cell lines in the lab that become cancerous when exposed to high levels of estrogen. They found that CBD caused many of these cancerous cells to die, while THC had no effect. CB1 and CB2 receptors were not involved in this protective benefit, but instead, CBD was killing cancer cells by activating TRPV1 receptors. TRPV1 receptors are known to be one of CBD’s many targets, and are not activated by THC, which explains its lack of effect in this specific type of cancer.

For some individuals, endometrial cancer responds well to treatment. But a substantial portion of patients remain unresponsive, leading to around 90,000 deaths a year. CBD represents a promising therapeutic option for those who have become unresponsive to traditional treatment approaches. However, we must temper our optimism until these findings can be replicated in human patients. Until then, our hope is limited to a petri dish.

Endocannabinoid System: Simple & Comprehensive Guide

THC Enhances the Pain-Relieving Effects of Opioids in Double-Blinded, Placebo-Controlled Study

Published: February 5, 2018

One way in which cannabis can combat the opioid epidemic is by reducing the amount of opioid medication needed for pain relief. THC is thought to synergize with opioids to have stronger pain-relieving effects, in combination, than either drug on their own. This enables THC to enhance the effect of low-dose opioids so as to reduce opioid consumption. The idea that cannabis reduces opioid use is well-supported, but has never been subjected to a double-blinded, placebo-controlled trial that is the gold standard of clinical research.

A recently published study in Neuropsychopharmacology implemented this double-blinded, placebo-controlled design to test the effect of smoked cannabis (0% or 5.3% THC) in combination with oxycodone at either the lowest pain relieving dose (5 mg) or sub-threshold (2.5 mg). The scientists found that neither cannabis, nor the sub-threshold dose of oxycodone was effective at increasing pain thresholds in humans. However, in combination, 5.3% THC cannabis and sub-threshold oxycodone caused substantial pain reduction.

Since neither drug was effective at reducing pain on their own, these findings suggest that there’s an interaction between THC and opioids through CB1 (activated by THC) and µ-opioid receptors (activated by the opioid chemical in oxycodone). Indeed, there’s evidence that CB1 receptors and µ-opioid receptors can couple so that activation of one enhances the effects of the other. This could explain why activation with low doses of THC or opioids on their own is insufficient, but together, relieves pain.

This study builds on an increasing body of evidence showing that cannabis either replaces opioids or decreases their use. Even if cannabis merely prevents the escalation of opioid consumption, it would have important consequences.

Lead image: skynesher/iStock

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Josh Kaplan
Josh Kaplan
Josh Kaplan, PhD, is an Associate Professor of Behavioral Neuroscience at Western Washington University. He is a passionate science writer, educator, and runs a laboratory that researches cannabis' developmental and therapeutic effects.
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