What is Chronic Pain
Pain is the body’s normal response to trauma or illness and usually goes away once healing has taken place. However, acute pain can occasionally evolve into a more chronic pain condition in which pain persists, often for months or even longer. Chronic pain may broadly be divided into three categories:
- Nociceptive pain results from ongoing tissue damage such as arthritis in a joint
- Neuropathic pain stems from the dysfunction of neurons in our peripheral and central nervous system
- Mixed pain results from a combination of the two
Chronic pain is marked by pain that lasts longer than six months and is often accompanied by other conditions that involve long-term pain such as certain cancers, stroke, fibromyalgia, chronic fatigue syndrome, endometriosis, and inflammatory bowel disease.
Chronic pain appears to be linked to abnormalities in the interaction between certain glands (e.g., the hypothalamus, pituitary, and adrenal glands) and the nervous system it is known as a “stress axis” that controls reactions to stress, injury, and trauma. However, more recently, the role of the endocannabinoid system (ECS) in analgesia has been demonstrated, with a certain level of control independently being mediated through the ECS along with endogenous opioids.
Several studies have established that the role of the ECS in pain and pain relief is primarily mediated through CB1 and CB2 receptors, but may also involve other receptors like VR1 and glycine receptors as well as interactions with pre-existing pathways, and behavioral modulation. In addition, the endocannabinoids, anandamide, and 2-AG which act as neurotransmitters, have the ability to regulate and modulate the ascending (nociceptor) and descending (inhibitory) pain signaling pathways.
Symptoms of Chronic Pain Syndrome
Symptoms vary from person to person but may include any or a combination of:
- Low back pain
- Joint pain
- Muscle aches
- Burning, stinging, or tingling pain in different parts of the body
- Jolts of sharp or shooting pain
- A dull ache, throbbing, or squeezing sensation
- General soreness and stiffness
However, because chronic pain can cause disabilities that can interfere with daily life, it can take a toll on self-esteem that can cause feelings of anger, depression, anxiety, and frustration along with other symptoms that can include:
- Feeling fatigued, tired, or wiped out
- Loss of appetite
- Trouble sleeping
- Feeling weak and lacking energy
Chronic Pain Syndrome Medications & Treatments
The main goal of the treatment of chronic pain is to reduce pain, boost mobility and help a return to daily activities without discomfort. Because the severity and frequency of chronic pain can differ from patient to patient, pain management plans can include medical treatments, lifestyle remedies, or a combination of these methods to focus on individual symptoms and any underlying health conditions.
There are several different types of medications available to help treat chronic pain. Over-the-counter pain relievers such as acetaminophen (Tylenol) or nonsteroidal anti-inflammatory drugs (NSAIDs) such as aspirin (Bufferin) or ibuprofen (Advil) are usually the first option. For more severe pain, opioid pain relievers, including morphine (MS Contin), codeine, and hydrocodone (Tussigon) are prescribed. However, these come with a range of negative side-effects and can be highly addictive. Sometimes adjuvant analgesics, such as antidepressants and anticonvulsants are also prescribed.
In certain cases, non-drug medical procedures can also provide relief from chronic pain. These include electrical stimulation, which reduces pain by sending mild electric shocks into your muscles, nerve block injections that prevent nerves from sending pain signals to your brain, or surgery, which corrects injuries that may have healed improperly and that may be contributing to the pain.
Alternative therapies and lifestyle changes are also helpful, especially in conjunction with more traditional pain treatments. These can include acupuncture, behavior modification, such as cognitive-behavioral therapy and psychotherapy, biofeedback, hypnosis as well as occupational therapy, and physical therapy. In addition, relaxation techniques, such as meditation, visual imagery, or deep breathing are also known to help.
CBD for Chronic Pain Syndrome
Research & Scientific Evidence
Cannabidiol (CBD) for pain is relatively well documented in the scientific literature. There is an increasing body of good evidence pointing to the fact that CBD has the ability to effectively relieve chronic pain by means of several different mechanisms.
In a seminal 2007 paper published in the European Journal of Pharmacology, scientists investigated CBD’s therapeutic potential for neuropathic (sciatic nerve chronic constriction) and inflammatory pain in rats.
Neuropathic and inflamed rats received oral cannabidiol or its vehicle; neuropathic rats received cannabidiol doses of 2.5, 5, 10, and 20 mg/kg, inflamed rats were given 20 mg/kg and the control rats were given a placebo. The CBD treatment/placebo was given once a day for a week, starting from day 7 after neuropathic pain or inflammation was induced. The efficacy of the CBD treatments was assessed using both behavioral as well as biochemical tests.
The researchers found that CBD produces an anti-hyperalgesic effect in neuropathic and inflamed rats possibly via acting as a CB1, CB2, and TRPV1 receptor antagonist. They posit that CBD inhibits the cellular uptake and enzymatic hydrolysis of the endocannabinoid anandamide which is involved in pain control through activation of cannabinoid CB1 and CB2 receptors. Because of this, the result is enhanced levels of anandamide outside and inside the cell, which in turn accounts for CBD’s anti-hyperalgesic and anti-inflammatory actions.
Investigating the interaction of CBD with the 1-⍺ and ⍺-1-β glycine receptors thought to play a key role in the development of chronic pain following inflammation or nerve injury, the researchers published their results in a 2009 paper in the journal Pharmacology.
The researchers utilized a standard whole-cell experiment protocol to apply a CBD solution to 1-⍺ and ⍺-1-β glycine receptors in human kidney cells. CBD has applied either alone, in order to determine its direct agonistic effects, or in combination with a sub-saturating glycine concentration, in order to determine its glycine-modulatory effects.
From the data, they concluded that CBD targets and modulates 1-⍺ and ⍺-1-β glycine receptors and implicates this interaction for some of its anti-inflammatory and neuroprotective properties. Moreover, because the inhibitory postsynaptic transmission in the spinal cord involves mainly glycine, CBD has the potential as a therapeutic agent that inhibits pain sensitization without producing sedation or other central nervous effects.
In a 2019 study published in the journal Pain, researchers wanted to provide new insights into the therapeutic efficacy of CBD and its mechanism of action in allodynia and anxiety-like behavior in chronic neuropathic pain.
Adult male rats were divided into naïve, sham, and neuropathic pain induced experimental groups. For acute in vivo dose-response electrophysiological experiments, cumulative injections of CBD (0.05-0.25 mg/kg) were given while 5 mg/kg/day for 7 days were administered for the repeated condition. The effects and mechanisms of CBD were assessed using in vivo electrophysiology, mechanical allodynia, and behavioral assays.
The researchers found that treatment with CBD reduced mechanical allodynia, decreased anxiety-like behavior, and normalized 5-HT activity. In addition, repeated treatment with low-dose CBD induced analgesia predominantly through TRPV1 activation in chronic neuropathic pain conditions.
CBD is popular for use as an analgesic, with many people reporting that they use it successfully for relieving pain in a variety of conditions including everything from tennis elbow to rheumatic discomfort, fibromyalgia, and chronic pain.
CBD as a Complementary Treatment
CBD can also be an effective complementary therapy to help reduce many of the symptoms accompanying chronic pain. CBD can reduce feelings of depression and anxiety as well as mediate insomnia and other types of sleep difficulties by promoting REM sleep. However, one area in which CBD can be of great benefit to chronic pain patients is to help them reduce the amount of opioid medications they need while simultaneously aid in recovering from opioid addiction. One particular study concluded that CBD’s anxiolytic properties and minimal adverse side effects support its viability as a treatment option for a variety of symptoms associated with opioid addiction.
Chronic pain is a ubiquitous and debilitating problem that affect a large number of people of all ages, genders, and walks of life. Humans have known about the pain-relieving properties of cannabis for millennia, but the use of phytocannabinoids in medical practice has been impeded due to legislation as well as their adverse psychoactive effects. CBD circumvents both of these concerns and current research has the potential to shape treatments to provide millions of people with an effective and safe form of pain relief. However, speak to your treating physician before using CBD for chronic pain as he or she can monitor dosage, symptom improvements, and other clinical parameters such as potential drug interactions.