Depression and chronic pain

Chronic pain has been shown to be significantly correlated with depressive disorders. It falls into the category of external stressors which can influence the development of depressive disorders. Research has shown that depression and states of chronic pain can be influenced by similar neurobiological mechanisms, still, the exact correlation and understanding of their association is not completely clear. Research regarding this topic is key in better understanding the connection between these states and thus help create new and more efficient treatment methods.

For more information about depression read:

For more information about states of chronic pain read: https://helpmedix.com/en/news/263-what-is-chronic-pain

Depression is often characterized by feelings of persistent sadness, lack of energy and motivation, less interest in activities, changes in sleep and appetite and suicidal thoughts and behaviors, it is necessary for the symptoms to last at least two weeks.

Chronic pain is usually defined as a consistent or intermittent pain that lasts longer than the time required for the tissue to heal, which is typically around 3 months. It can persist even if there is no evident physiological cause to the pain.

Clinical research has shown that chronic pain, acting as a stressor, often induces depression. One study has shown that up to 85% of patients suffering from chronic pain have been shown to also suffer from depression. The most significant effect on higher risk of depression has been shown to be pain disability, not how intense the pain is but how much it disables everyday functioning.

Depression has a negative influence on the recovery prognosis when chronic pain is in question and vice versa, these two states worsen each other and are more difficult to treat when they are paired up rather than separate. 

Chronic pain affects everyday life, stress tolerance and physical activity, which can lead to feelings of isolation and anxiety. Chronic pain also significantly negatively affects sleep quality, which directly worsens the risk of depression.

Physiological causes

The physiological mechanisms which would explain the correlation between chronic pain and depression aren’t completely clear, this represents a significant challenge for researchers and the development of treatment. Still, what has been shown is that these two states have significant overlapping in aspects of their effect on neuroplasticity changes and neurobiological mechanism.

Brain regions which play a role in the neural networks related to injury and bodily pain are also included in the regulation of mood. These regions are the insular cortex, prefrontal cortex, anterior cingulate, thalamus, hippocampus, and amygdala. This speaks to the similarities in brain regions involved in information processing regarding these two states.

Neuroplasticity is a mechanism which allows adaptive, structural and functional changes in brain tissue, it is the ability of the brain to reorganize itself in accordance with different damage it has suffered so as to continue functioning in the most optimal way possible.

The dopaminergic system in the brain effects neuroplastic changes in depression and chronic pain, persistence of chronic pain can damage the dopamine activation system.

It has been shown in many studies that there is a lower volume and number of synapses in the prefrontal cortex and hippocampus in depressive patients, more drastic the more intense the depression is. The connection between the prefrontal cortex and the development of pain, through the nucleus accumbens (which also has a role in motivation, behavior, and a multitude of mental disorders, including depression) has also been confirmed. This implies similar maladaptive neuroplastic changes which lead to depressive symptoms and the development of chronic pain. These maladaptive changes in neuroplasticity can also include neural pathways from the peripheral to the central nervous system and are involved in creating and maintaining chronic pain.

In summary, a multitude of neurobiological and molecular mechanisms, of which only some are listed here, are involved in connecting depression and chronic pain. Unfortunately, science still doesn’t have the complete picture of the process which makes the comorbidity of these two states so common. Still, significant findings are being made which allow the development of treatment methods.

Treatment

Pharmacotherapy which includes antidepressants and pain medication is used in treatment, but research doesn’t suggest significant efficacy. There is a growing trend of using nonpharmaceutical methods for treating these states when they are paired such as psychotherapy, acupuncture, hypnosis and physical exercise.

Opioids are the most effective in treating chronic pain, the problem with them is a high rate of dependency and addiction. The role of opioids in treating depression is also still unclear, there are claims that long- term opioid use might worsen depression risk.

Another group of pharmaceuticals which efficiently treat chronic pain are benzodiazepines. Besides treating chronic pain, they are also used for treating anxiety and insomnia, both regularly seen in patients suffering from chronic pain and depression. Benzodiazepines have a high rate of abuse, which can lead to addiction and serious cognitive consequences. 

Psychotherapy is a key element to the process of treating chronic pain and chronic pain induced depression. The development of this type of depression is influenced by psychosocial factors, which are important to understand in the therapeutic process.

Research has shown that the application of psychotherapy in children and adolescents who suffer from chronic headaches can help significantly reduce pain. The use of psychotherapy, such as cognitive behavioral therapy (CBT) can significantly help understanding and overcoming the difficulties created by chronic pain. Psychotherapy drastically improves the treatment success prognosis of chronic pain and chronic pain induced depression.

Written by: Bachelor of Psychology, Aleksa Holcer.

Sheng, J., Liu, S., Wang, Y., Cui, R., & Zhang, X. (2017). The Link between Depression and Chronic Pain: Neural Mechanisms in the Brain. Neural Plasticity, 2017, 1–10. https://doi.org/10.1155/2017/9724371

Meda, R. T., Nuguru, S. P., Rachakonda, S., Sripathi, S., Khan, M. I., & Patel, N. (2022). Chronic Pain-Induced Depression: A Review of Prevalence and Management. Cureus. https://doi.org/10.7759/cureus.28416

*This text is intended for informational purposes only. If you experience any symptoms, it is recommended that you seek advice from your doctor or a qualified healthcare professional.*

*Image taken from the site: https://pixabay.com/photos/back-pain-body-pain-ergonomics-6949392/*