The Link Between Anxiety and Chronic Pain

Posted: August 2024

Author: Katie Donnelly, Adv Dip HSc Naturopathy

Phytobrief - Chronic Pain and Anxiety

The correlation between chronic pain and altered psychological balance is well established. More recent focuses, however, have explored the role of pain perception, and how mental wellbeing can influence pain identification. This highlights a complex relationship, whereby chronic pain can induce anxiety conditions, and anxiety can enhance the interpretation of pain signals. Ongoing concerns surrounding opioid-based medications, and the implications on mental health, are also a consideration. Such developments further support the opportunity for phytotherapy solutions.¹

Pain

Pain is subjectively measured and is influenced by the concepts of pain tolerance and overall resilience to pain intensity. Where pain tolerance is lower, mental health is more likely to be impaired. Anxiety related to pain is one of the most frequently occurring emotional challenges. This can enhance pain sensations, perceived duration, and increases the expectation that pain will ensue. Associated feelings of depression, fear, reduced quality of life, increased reliance on substances, and isolation also contribute.²

The multi-action ability of plant medicine can be beneficial in this regard. Corydalis yanhusuo (Corydalis) has been used for centuries as an analgesic and is also known for sedative actions. The isoquinoline alkaloids contribute to its analgesic action.³

Corydalis and its potent pain-relieving alkaloids, specifically, Tetrahydropalmatine, have shown to act as a powerful analgesic, anxiolytic, and sedative, calming sensations of pain and anxiety.⁴ Reduced reactive oxygen species and pro-inflammatory markers contribute to this action. Downregulation of transient receptor potential vanilloid 1 (TRPV1) and purinergic ion channel type 3 receptor pathways further reduces pain signalling.⁵ Regulation of the hypothalamic-pituitary- adrenal axis, and subsequent neurotransmission balance, then contributes to reduced symptoms of anxiety.

Current pharmaceutical pain medications also present potential side effects. Acetaminophen, non-steroidal anti-inflammatory drugs, and opioid medications are amongst commonly prescribed nociceptive pain medications. Long term use, however, can result in complications including liver damage, gastrointestinal complications, addiction and inappropriate use.⁶ Alkaloids in Corydalis have demonstrated anti-addiction activity, inhibiting the effects of morphine and methamphetamine.⁵

A powerful anti-inflammatory, Curcuma longa (Turmeric) shows clinically researched benefit for pain from osteoarthritis and Rheumatoid arthritis. Degenerative damage to cartilage and subsequent swelling, pain, and joint distortion can cause considerable disturbance to quality of life. Turmeric supplementation reduced pain and inflammation, via inhibition of nuclear factor kappa- beta by curcuminoids. Antioxidant properties from terpenoids and polyphenols further supressed reactive oxygen species.⁷

In musculoskeletal pain, inhibition of cyclo-oxygenase 2 and prostaglandin E2 by curcumin resulted in analgesic actions, in vivo. When combined with Boswellia serrata (Boswellia), Turmeric further improved patient pain perception. This was comparative to acetaminophen.⁸ Interactions with TPRV1 and inhibition by curcumin may contribute to these actions.

Anxiety

The rates of anxiety amongst people with chronic pain is generally considered to be five times higher than those without pain. Part of the connection between pain and anxiety is attributed to systemic inflammation, with increased central nervous system (CNS) pro-inflammatory cytokines. This can result from chronic pain, stress and sleep disturbance.⁹ Herbal medicine that addresses both inflammation and psychological wellbeing can be particularly beneficial.

Eschscholtzia californica (Californian poppy) has been used traditionally to support mood and pain. Nervous system regulation has been noted through alkaloid interactions with gamma-aminobutyric acid receptors. Protopine and allocryptopine are primarily attributed with these actions, also acting as catecholamine inhibitors. The high alkaloid content of California poppy then provides analgesic actions. As a gentle sedative, this herb can further support sleep disrupted by pain and psychological imbalance.¹⁰

Commonly used for depression, Hypericum perforatum (St. John’s wort) is similarly efficacious for anxiety conditions. This herb has been deemed more effective than certain selective serotonin reuptake inhibitors, particularly Fluoxetine, with fewer side effects.¹¹ Delayed or inhibited uptake of dopamine and norepinephrine also contributes. These mechanisms may also be behind altered pain perception on supplementation with St John’s Wort. As an anti-inflammatory and vulnerary herb, St John’s Wort has also demonstrated pain relief from osteoarthritis when applied topically.¹²

Humulus lupulus (Hops) is another herb primarily known as a gentle sedative and nervine. Recent clinical studies support this, with Hops reducing stress and anxiety when taken daily, over a four-week period. When used in combination with Rosmarinus officinalis (Rosemary) and oleanolic acid, Hops also reduced arthritic pain. Decreased inflammatory cytokines and prostaglandin presence were thought to contribute to this.¹³

The concomitant occurrence of pain and anxiety is a prevalent issue for health professionals, with pain perception an important consideration. The ability of phytotherapy to effectively nourish the nervous system and provide analgesic actions make it a viable treatment option.

References

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3. Alhassen L, Dabbous T, Ha A, Dang LHL, Civelli O. The Analgesic Properties of Corydalis yanhusuo. Molecules. 2021 Dec 10;26(24):7498. https://doi.org/10.3390/molecules26247498 https://doi.org/
4. Zhang J, He S, Wang J. A Review of the Traditional Uses, Botany, Phytochemistry, Pharmacology, Pharmacokinetics, and Toxicology of Corydalis yanhusuo. Natural Product Communications. 2020;15(9). https://doi.org/10.1177/1934578X20957752
5. Du Q, Meng X, Wang S. A Comprehensive Review on the Chemical Properties, Plant Sources, Pharmacological Activities, Pharmacokinetic and Toxicological Characteristics of Tetrahydropalmatine. Front Pharmacol. 2022 Apr 26;13:890078. https://doi.org/10.3389/fphar.2022.890078
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8. Rudrappa GH, Murthy M, Saklecha S, Kumar Kare S, Gupta A, Basu I. Fast pain relief in exercise-induced acute musculoskeletal pain by turmeric-boswellia formulation: A randomized placebo-controlled double-blinded multicentre study. Medicine (Baltimore). 2022 Sep 2;101(35):e30144. https://doi.org/10.1097/MD.0000000000030144.
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10. Becker A, Yamada Y, Sato F. California poppy (Eschscholzia californica), the Papaveraceae golden girl model organism for evodevo and specialized metabolism. 2023; 14. https://doi.org/10.3389/fpls.2023.1084358
11. Canenguez Benitez JS, Hernandez TE, Sundararajan R, Sarwar S, Arriaga AJ, Khan AT, Matayoshi A, Quintanilla HA, Kochhar H, Alam M, Mago A, Hans A, Benitez GA. Advantages and Disadvantages of Using St. John's Wort as a Treatment for Depression. Cureus. 2022 Sep 22;14(9):e29468. https://doi.org/10.7759/cureus.29468.
12. Galeotti N. Hypericum perforatum (St John's wort) beyond depression: A therapeutic perspective for pain conditions. J. Ethno. 2017; 200: 136-146. https://doi.org/10.1016/j.jep.2017.02.016
13. Carbone K, Gervasi F. An Updated Review of the Genus Humulus: A Valuable Source of Bioactive Compounds for Health and Disease Prevention. Plants. 2022; 11: 3434. https://doi.org/10.3390/plants11243434