Unraveling Bipolar Disorder and the Cortisol, Thyroid Hormones link: Insights from Genetics
Introduction: Bipolar disorder is a complex mental health condition characterized by extreme mood swings, ranging from manic highs to depressive lows. While the exact causes, evidently there’s more than one, of bipolar disorder remain elusive, research has increasingly focused on the role of cortisol, thyroid hormones and genetic factors in its development and progression.
My research down this rabbit hole has only begun, I imagine, but I intend to start down it anyway. Let’s see exactly what we can discover.
The Role of Cortisol and Thyroid Hormones:
Cortisol, often referred to as the “stress hormone,” plays a crucial role in the body’s response to stress and regulates various physiological processes, including metabolism, immune response and inflammation. Thyroid hormones, on the other hand, primarily control metabolism and energy production. Both cortisol and thyroid hormones can influence mood and mental health, and disruptions in their levels have been implicated in bipolar disorder.
Cortisol and Bipolar Disorder
Research suggests that individuals with bipolar disorder may have dysregulated cortisol levels, with some studies indicating higher cortisol levels during manic episodes and lower levels during depressive episodes.
Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which governs cortisol production, has been implicated in bipolar disorder. Fluctuations in cortisol levels may contribute to mood instability and symptom severity in individuals with the condition.
Chronic stress, a known trigger for HPA axis dysregulation and cortisol release, may exacerbate bipolar symptoms and increase the risk of mood episodes.
Abnormalities in cortisol signaling pathways and sensitivity to cortisol have also been observed in individuals with bipolar disorder, further underscoring the role of cortisol in the pathophysiology of the condition.
- Cortisol is a steroid hormone produced by the adrenal glands in response to stress. It plays a vital role in regulating metabolism, immune response and the body’s fight-or-flight response. In individuals with bipolar disorder, dysregulation of cortisol levels has been observed, leading to heightened stress responses and potential exacerbation of mood symptoms.
Research has shown that chronic stress can lead to sustained elevation of cortisol levels, which may contribute to the onset of manic or depressive episodes in individuals with bipolar disorder. Additionally, abnormalities in the hypothalamic-pituitary-adrenal (HPA) axis, the brain circuitry responsible for regulating cortisol secretion, have been implicated in the pathophysiology of bipolar disorder.
In otherwords, It’s like the body’s stress alarm system is constantly malfunctioning.
Thyroid Hormones and Bipolar Disorder
Thyroid dysfunction, including hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid), has been associated with mood disturbances and psychiatric symptoms, including bipolar disorder.
Both hypo- and hyperthyroidism can mimic or exacerbate symptoms of bipolar disorder, leading to misdiagnosis or treatment challenges.
Studies have shown a higher prevalence of thyroid abnormalities in individuals with bipolar disorder compared to the general population, suggesting a potential link between thyroid function and mood regulation.
Thyroid hormones influence neurotransmitter systems, including serotonin and dopamine, which are implicated in mood regulation and may contribute to the development or exacerbation of bipolar symptoms.
- Thyroid hormones, including thyroxine (T4) and triiodothyronine (T3), are essential for regulating metabolism, energy production and mood. Abnormalities in thyroid function, such as hypothyroidism (low thyroid function) or hyperthyroidism (excessive thyroid function), have been associated with mood disturbances and may influence the course of bipolar disorder.
Studies have also shown that individuals with bipolar disorder are more likely to have thyroid dysfunction compared to the general population. Thyroid abnormalities, particularly hypothyroidism, can manifest with symptoms similar to those of depression, such as fatigue, lethargy and low mood, making it challenging to differentiate between the two conditions.
In simpler terms, thyroid issues like having too little (hypothyroidism) or too much (hyperthyroidism) thyroid hormone can mess with your mood and even mimic symptoms of bipolar disorder, making it hard for doctors to diagnose or treat correctly.
(My immediate thought is purhaps individuals with ‘thyroid dysfunction’ develope what we call bipolar disorder. But I’m not a doctor, so let’s just read on…)
Integration of Genetic Factors
Genetic factors play a significant role in the regulation of cortisol and thyroid hormones, as well as the development of bipolar disorder. Genetic variations in genes involved in the HPA axis and thyroid function have been implicated in bipolar disorder susceptibility.
For example, polymorphisms in genes encoding cortisol receptors, such as the glucocorticoid receptor gene (NR3C1), have been associated with altered stress responses and increased risk of mood disorders, including bipolar disorder. Similarly, variations in genes involved in thyroid hormone synthesis and metabolism, such as the thyroid peroxidase (TPO) gene, may influence thyroid function and contribute to bipolar disorder susceptibility.
Understanding the genetic underpinnings of cortisol and thyroid hormone dysregulation in bipolar disorder can provide valuable insights into the underlying mechanisms of the condition and inform personalized treatment approaches. By identifying specific genetic variants associated with cortisol and thyroid abnormalities, clinicians can tailor interventions to address the unique needs of each individual, ultimately improving outcomes for those living with bipolar disorder.
In summary, cortisol and thyroid hormones play important roles in regulating mood and physiological processes that are relevant to bipolar disorder. Dysregulation of cortisol levels and thyroid function may contribute to the onset, severity and course of bipolar disorder symptoms.
Further research is needed to elucidate the underlying mechanisms linking cortisol, thyroid hormones and bipolar disorder and to explore potential therapeutic interventions targeting these systems.
Similarly, thyroid hormones, including thyroxine (T4) and triiodothyronine (T3), play a vital role in regulating metabolism, mood, and energy levels. Research suggests that abnormalities in thyroid function, such as hypothyroidism or hyperthyroidism, may be associated with mood disturbances and could influence the course of bipolar disorder.
My First Question then...
Do doctors who suspect bipolar disorder test for thyroid issues in their patient before coming to a conclusion about bipolar disorder?
It would appear, that while it’s not universal practice for doctors to test for thyroid issues in every patient suspected of having bipolar disorder, it’s certainly common for healthcare providers to consider thyroid function as part of the diagnostic process. Here’s why:
Overlap in Symptoms: Bipolar disorder and thyroid disorders can share similar symptoms, such as mood swings, fatigue and changes in appetite or weight. Given this symptom overlap, thyroid dysfunction can sometimes mimic or exacerbate symptoms of bipolar disorder, leading to misdiagnosis or complicating treatment.
Prevalence of Thyroid Dysfunction: Research has shown that individuals with bipolar disorder are more likely to have thyroid dysfunction compared to the general population. Therefore, assessing thyroid function can be relevant, especially when there are symptoms suggestive of both conditions.
Comprehensive Assessment: A comprehensive assessment for bipolar disorder typically involves evaluating various factors, including medical history, symptoms, family history and sometimes laboratory tests. Thyroid function tests may be included as part of this evaluation to rule out any underlying thyroid issues that could be contributing to or exacerbating mood symptoms.
Rule-Out Approach: In some cases, doctors may follow a “rule-out” approach, meaning they aim to rule out other potential causes of symptoms before arriving at a diagnosis of bipolar disorder. Testing for thyroid dysfunction can be part of this process to ensure that mood symptoms are not solely attributable to thyroid abnormalities. (Which leads me, initially anyway, to believe that might be a possibility.)
Overall, while not every patient suspected of having bipolar disorder will undergo thyroid testing, it’s a consideration for many healthcare providers, especially when there are overlapping symptoms or risk factors suggesting the possibility of thyroid dysfunction.
Blood Tests
To test for thyroid issues, doctors typically order blood tests to measure levels of thyroid hormones and thyroid-stimulating hormone (TSH). These tests include:
Thyroid-Stimulating Hormone (TSH) Test: This test measures the level of TSH, a hormone produced by the pituitary gland that stimulates the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3). High TSH levels may indicate hypothyroidism, while low TSH levels may suggest hyperthyroidism.
Thyroid Hormone Tests: These tests measure the levels of T4 and T3 in the blood. Low levels of T4 and/or T3 may indicate hypothyroidism, while high levels may suggest hyperthyroidism.
Thyroid Antibody Tests: In some cases, doctors may order tests to detect antibodies that attack the thyroid gland, such as thyroid peroxidase antibodies (TPO antibodies) and thyroglobulin antibodies. Elevated levels of these antibodies may indicate autoimmune thyroid disorders, such as Hashimoto’s thyroiditis or Graves’ disease.
These simple blood tests are typically performed in a lab, and the results are interpreted by healthcare providers to assess thyroid function and diagnose any thyroid disorders. Depending on the results and clinical presentation, further evaluation or referral to an endocrinologist may be warranted for diagnosis and management.
Genetic Testing
The Importance of Genetic Testing: Genetic testing offers a unique opportunity to uncover underlying genetic predispositions to bipolar disorder and related hormonal dysregulations. By analyzing an individual’s DNA, genetic tests can identify specific gene mutations or variations associated with bipolar disorder and provide valuable information about potential treatment targets.
Although genetic testing can provide valuable insights into a person’s predisposition to certain thyroid disorders, especially those with a known genetic component, such as autoimmune thyroid diseases like Hashimoto’s thyroiditis and Graves’ disease, genetic testing alone may not directly detect thyroid dysfunction or hormone levels.
However, genetic tests can identify specific gene mutations or variations associated with thyroid disorders, which may help in assessing the risk of developing these conditions. For example, variations in genes involved in thyroid hormone synthesis (e.g., thyroid peroxidase gene) or autoimmune thyroid diseases (e.g., HLA genes) may indicate an increased susceptibility to thyroid dysfunction.
While genetic testing can offer information about genetic predispositions, it is typically used in conjunction with other diagnostic tests, such as blood tests measuring thyroid hormone levels and thyroid antibodies, to provide a comprehensive assessment of thyroid function and disorders.
In summary, while genetic testing can reveal genetic factors that may predispose individuals to thyroid disorders, it is not a direct measure of thyroid function or hormone levels. Blood tests remain the primary method for diagnosing thyroid dysfunction and assessing thyroid hormone levels.
Conclusion: In conclusion, understanding the intricate interplay between cortisol, thyroid hormones and genetic factors is essential for unraveling the complexities of bipolar disorder.
Here are some studies and websites that address the relationship between cortisol, thyroid hormones and bipolar disorder you might be interested in:
Resources:
- McEwen, B. S. (2008). Stress, the HPA axis, and the hippocampus: Implications for PTSD and depression. European Journal of Pharmacology.
- Bauer, M., Silverman, D. H., Schlagenhauf, F., London, E. D., Geist, C. L., van Herle, K., … & Whybrow, P. C. (2005). Thyroid Function and Bipolar Affective Disorder. Psychiatry Research: Neuroimaging.
- Ozcan, M. E., Gulec, M., & Ozerol, E. (2007). Cortisol and thyroid hormones in patients with bipolar disorder during lithium intoxication and after pharmacotherapy. Progress in Neuro-Psychopharmacology and Biological Psychiatry.
- Young, A. H., & Juruena, M. F. (2015). The role of cortisol in mood disorders. In: Handbook of Clinical Neurology, 124, 383–395.
- Bauer, M., & Glenn, T. (2015). Thyroid hormones, serotonin and mood: of synergy and significance in the adult brain. Molecular Psychiatry, 20(10), 1065–1077.
- Bauer, M., & Whybrow, P. C. (2001). Thyroid hormone, neural tissue, and mood modulation. In: Neuropsychopharmacology: The Fifth Generation of Progress, 1025–1038.
- Pathak, L., Agrawal, A., & Dhir, A. (2013). Natural products and metabolites as psychotherapeutic agents. In: Evidence-Based Validation of Herbal Medicine, 201–222.
Studies:
- “Stress, the HPA axis, and the hippocampus: Implications for PTSD and depression”
Authors: McEwen, B. S. / Journal: European Journal of Pharmacology / Year: 2008 / Link: PubMed
- “Thyroid Function and Bipolar Affective Disorder”
Authors: Bauer, M., Silverman, D. H., Schlagenhauf, F., London, E. D., Geist, C. L., van Herle, K., … & Whybrow, P. C. / Journal: Psychiatry Research: Neuroimaging / Year: 2005 / Link: PubMed
- “Cortisol and thyroid hormones in patients with bipolar disorder during lithium intoxication and after pharmacotherapy”
Authors: Ozcan, M. E., Gulec, M., & Ozerol, E. / Journal: Progress in Neuro-Psychopharmacology and Biological Psychiatry / Year: 2007 / Link: PubMed
Websites:
- National Institute of Mental Health (NIMH)
- Link: NIMH – Bipolar Disorder
- American Thyroid Association (ATA)
- Link: ATA – Bipolar Disorder and Thyroid
These studies and websites offer valuable insights into the relationship between cortisol, thyroid hormones, and bipolar disorder, shedding light on the complex interplay between these factors in the context of mental health.
Disclaimer: The information and/or products mentioned in these article are provided as information resources only and are not to be used or relied on to diagnose, treat, cure or prevent any disease. The statements made in this article have not been evaluated by the Food and Drug Administration. Any products mentioned are not intended to diagnose, treat, cure, or prevent any disease, but rather to be considered as an informational resource only to encourage critical thinking and personal research. The information in this article is intended for educational purposes only. The information is not intended to replace medical advice offered by licensed medical physicians. Please consult your doctor or health care practitioner for any and all medical advice.
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