Measuring Pain Relief from Cannabis: What the Evidence Says

What our evidence base tells us:

While Cannabis has been used for pain relief for centuries, with medical use of the substance dating back to Ancient Egypt and Assyria, we are only just beginning to get a grasp on the actual processes involved in pain relief and pain reception.

Fortunately, the evidence in this area is growing and The Academy of Medical Cannabis’ own, ground-breaking and comprehensive evidence base reviews the studies you need to know and gives us a clearer and easier-to-understand overview of this highly complex area.

It is believed that the analgesic activities of medications used for pain-relief are partially mediated by cannabinoid signalling.

More generally, the endocannabinoid system seems to play a large and highly important role in pain relief due to its role in the operation of the inhibitory and stimulatory pathways of the nervous system, although this phenomenon is yet to be fully understood.

Why is pain relief so hard to investigate?

Pain itself is a complex phenomenon with no singular defining characteristic.

Further, as there’s such a variety of different personal and anecdotal experiences surrounding pain and pain stimuli, the subject becomes even harder to look into objectively.

Because of this, observation and naturalistic studies (which are less rigorous and sometimes less well-regarded than lab-based experiments) help to provide insight into the many ways medicinal cannabis affects patients’ lives and their well-being.

Even with such allowances being made for the use of more naturalistic studies over purely lab-based investigations, pain remains a very hard topic to understand as we have to figure out what specific methodology we should use to most accurately measure pain.

How do we measure pain?

Because pain can be hard to describe and record in the laboratory, the approach taken in many pain studies is to use psychometric tests like the visual-analogue scale (VAS) or VAS pain scores. Psychometric tests rely upon the subjectivity of the participants in that moment in time to give a measurement of self-reported pain and well-being. VAS scores therefore provide insight into the ways that cannabinoids and cannabis-based products work as pain-relieving medicines, particularly as the drugs can be compared with placebo conditions or other analgesic drugs in this way.

However, a problem with this method is that as cannabis causes intoxication, the person reporting their lower pain score in this way may simply be reporting a decrease in pain due to the high they are experiencing. Yet, the effects of intoxication may form an important part of the pain-relieving effect of cannabis, and therefore is an important area for further research to explore.

Observational methods have also been used to measure the effects of cannabis in pain management, for example using patient records to compare the effects of medical cannabis to the effects garnered from opioid (and other analgesic medication) use.

Other methods of measuring and researching pain involve more lab-based experiments where brain measurements (e.g. EEG) or measurements of the nervous system are taken.

What some key studies say

Cooper et. Al. (2013): Here, Cooper et al used a cold pressor test to compare smoked cannabis with oral Dronabinol (THC) in regard to pain relief. Ultimately, the two conditions showed no difference in peak analgesic activity, but the oral dronabinol did demonstrate a longer lasting effect.

Wilsey et. al. (2016): Wilsey et. al. examined the analgesic activity of vaporized cannabis used for treating central neuropathic pain (related to spinal cord injury and disease). The results obtained suggested that the pain-relief was dependent upon the dose administered as inferred from the blood-concentrations of metabolites of THC. Generally, as the dose of cannabinoids increased, so did the reported analgesic activity.

It should be noted that further research is ongoing following this preliminary trial so more may be discovered about the use of herbal cannabis for the treatment of neuropathic pain.

van Amerongen G et. al. (2018): Conducted a study comparing oral THC to paracetamol in a cold-pain and pressure-pain test. The authors came to the conclusion that paracetamol as well as cannabis and promethazine weren’t significantly effective in reducing pain in this case, with them coming to the ultimate decision that the tests should be considered for future experiments.

Fibromyalgia, arthritis and chronic pain: Many intriguing and poignant studies have been carried out around cannabis’ role in treating chronic pain, arthritis and fibromyalgia.

For more information on these studies and the treatment of pain using medical cannabis, take a look at our evidence base, a ground-breaking systematic review of the history of research in this area and a global first-of-its-kind searchable database for clinical referencing.

The specific article focused on pain, where you can find out about the fibromyalgia, arthritis and chronic pain studies, is available to access and download in PDF form here.

Follow the link for more information on our online course in chronic pain management.

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