Can Cannabis Help Huntington's Disease Patients?

Overview

While research is still in its early phases, studies have found evidence supporting the use of cannabis for Huntington’s Disease. These studies suggest that cannabis may be able to help as a neuroprotectant, as well as reduce symptoms like irritability, uninhibited behavior, uncontrolled movements, and hypersalivation. It may also improve a patient’s cognitive measures, movement control, and the ability to walk.

While more research is needed, what research we do have gives hope that cannabis may help those suffering from Huntington’s Disease.

How Cannabis Works on Huntington’s Disease

The endocannabinoid system (ECS) exists in all vertebrates and helps regulate crucial functions such as sleep, pain, and appetite. The human body produces its own cannabinoids, which modulate and activate its various functions, but as its name suggests, the endocannabinoid system can also be modulated and activated by cannabinoids found in the cannabis plant. Because the entire system was only discovered in the past 30 years, scientists still have much to learn about the myriad ways cannabis affects the human body.

When it comes to Huntington’s Disease, scientists have discovered that the ECS plays an important role in the progression of the disease. In fact, some have even suggested that imbalance or deficiency of the endocannabinoid system is a cause of Huntington’s Disease.

As it turns out, there are several ways in which impairments of the endocannabinoid system have been linked to Huntington’s Disease.

For one thing, we see differences in important areas of the brain for patients with Huntington’s Disease compared to the general population. One important area is the basal ganglia, a part of the brain involved in movement. This part of the brain is usually rich with endocannabinoids, as well as the receptors they activate and the enzymes that break them down. But in post-mortem studies on patients with Huntington’s Disease, most patients have had a massive loss of CB1 receptors (one of the primary receptors for the endocannabinoid system) in the basal ganglia.

Other studies, on both animals and humans, show loss of this receptor in other areas of the brain related to Huntington’s Disease, as well. Some even suggest that a decrease in this receptor’s mRNA (a molecule that conveys genetic information) is the first sign of Huntington’s disease and a hallmark of its early stages. Animal studies have even tied loss of CB1 receptors to worsening motor function and the physiological development of Huntington’s Disease.

In late states of the disease, we also see increased levels of CB2 — another important receptor for the endocannabinoid system.

In addition, animal studies show a significant changes in the amount of key endocannabinoids like anandamide and 2-AG in the brains of Huntington’s Disease patients; with decreased levels in multiple parts of the brain as the disease progresses, and then an increase in anandamide in the cortex during late stages of the disease.

Generally, these insights suggest that there are region and stage specific impairments of the endocannabinoid system in Huntington’s Disease. Researchers suggest that both drugs that activate CB1 or CB2, or ones that inhibit them could potentially be helpful for treating this disease, but more research is needed to understand how to do this effectively.

Medical Studies on Huntington’s Disease and Cannabis

While the data on how the endocannabinoid system impacts Huntington’s Disease gives us some hope that cannabis might be able to help with this degenerative condition, we need to look at the direct research on using cannabinoids for Huntington’s Disease to learn when and how it could be effective. Unfortunately, the research is still in early phases, and is conflicted at points, but much of it suggests that cannabis could help.

To begin with, animal studies suggest that treatment with THC, the most common cannabinoid in the cannabis plant, can help with Huntington’s Disease as a neuroprotectant, potentially slowing the progression of the disease.

Some case studies also suggest that cannabis could help with the condition. In one case study from 2006, a female patient with Huntington’s Disease had significant improvements using cannabis, and later nabilone (a synthetic version of THC). Her caretakers found that using these cannabinoids improved her mood, reducing irritability, uninhibited behavior and angry outbursts. She became calmer and more patient and also saw improvement in her controlled movements with less chorea (involuntary dance-like movements common to Huntington’s Disease).

These positive results from case studies and animal research has led to studies of cannabis for Huntington’s Disease, some of which have brought back positive results.

A 2009 study on cannabis and Huntington’s Disease showed that patients treated with nabilone were found to have moderate improvements in motor skills, chorea, and cognition. Then, a 2012 study looked specifically at treating chorea with cannabis and found it caused moderate improvements. Unfortunately, in both cases the researchers used low doses so other researchers have pointed out these studies were underpowered to show more than these moderate improvements.

In a 2018 study, researchers reviewed previous literature on the topic and found that cannabis use could lead to improvement of motor symptoms, weight gain (a desired outcome in this case), behavior and mood. They found those using cannabis were less irritable, less apathetic, and experienced less hypersalivation.

Unfortunately, not all research on cannabis and Huntington’s Disease has come back with positive results. In fact, several clinical trials suggest that cannabis has no effect on the condition. For example, in a 2016 double‐blind, randomized, placebo‐controlled clinical trial using Sativex (a cannabis extract containing THC and CBD), no significant differences were found between those using Sativex and those using a placebo on measures of motor, cognitive, behavioral, and functional skills. In addition, no changes were noticed in important biomarkers for the condition. Still the authors of this study recommended it be replicated with higher doses of cannabis.

In other cases, research showed potential for cannabis to be detrimental to the condition. Animal studies have shown potential for THC to exacerbate some aspects of the condition, and in an uncontrolled clinical study, a single dose of nabilone left one patient with Huntington’s Disease with markedly increased chorea.

Still, the majority of the research leads scientists to feel hopeful that cannabis could be a helpful treatment — and should continue to be researched for its potential to treat Huntington’s Disease.

CBD and Huntington’s Disease

While most research on cannabis focuses on high THC varieties of the plant, or THC-based medicines, some have also looked at whether another component of the plant, CBD, might be helpful when used by itself. And there is reason to believe it may help with Huntington’s Disease.

In 2017, the World Health Organization reported that CBD may play a role in treating Huntington’s Disease and a 2018 review of the literature found that CBD has potential for helping with movement disorders including Huntington’s Disease.

In animal studies, CBD was even able to reverse neuronal loss from toxicity in Huntington’s Disease. However, in some controlled clinical trials, patients treated with CBD did not show improvements. Still some researchers suggest these experiments need to be done with higher dosages.

Potential side effects of cannabis use

In studies on cannabis use in Huntington’s Disease, patients experienced side effects such as nausea, increased weakness, behavioral or mood changes, suicidal ideation, hallucinations, dizziness, fatigue, and feelings of intoxication. These studies were primarily using lower doses of cannabis. But those taking higher doses that include THC may also experience anxiety and in rare cases, psychosis.