Thyroid-Brain Crosstalk-Part 2: Serotonin and Thyroid Interactions

One of the things that is common in hypothyroid patients is that many of them are on antidepressants.  However, none of the antidepressant medications actually raise the quantity of the neurotransmitter that the medication is targeting.  They only allow the neurotransmitter to remain in the synaptic cleft for a longer period of time.

They may have chronic brain issues because they are not getting proper serotonergic activity but the pharmaceutical model doesn’t enhance the serotonergic system, it only allows it to have a short-term effect of increasing neurotransmission.

 Effects of Thyroid Hormone Deficiency on Serotonin

  • Decreases cortical serotonin concentrations
  • Decreased quantity of peripheral serotonin
  • Decreased 5-HT density in the brain
  • Increased serotonin turnover in the brain stem
  • Diminished central and peripheral serotonergic activity

When people are thyroid deficient, they don’t make as much central and peripheral serotonin, the receptor sites are produced in decreased quantity in the brain and they get decreased activation of their serotonin system overall.

If this happens for years and years, this will lead to permanent neurodegeneration of serotonergic neurons.

There are a number of studies that support the view that the serotonergic system starts to fail in hypothyroid disorders:

“Thyroid hormone has been shown to activate the serotonin receptors in the frontal cortex”

When thyroid levels are low, they have decreased serotonin activity and many of these people get depressed.  They continue to have depression even after going on thyroid hormone because these serotonergic systems have degenerated and they are less efficient.

“Losses of cortical serotonin receptors appears to be a consequence of hypothyroidism at the level of the serotonin system of the brain”

Enhancing the Serotonergic System

In the natural medicine model, we can actually enhance the serotonergic system.  This is well-published in the literature.  Many natural compounds can actually increase the quantity of serotonin.

What unfortunately happens to some of these people who have been hypothyroid for a long period of time, they not only have their glial cells activated, but their neurotransmitter pathways become less efficient.  When neurons don’t get activation, they degenerate and die.  Imagine this has been going on for a decade. What happens to their serotonergic pathways of their brain?  They permanently degenerate. Sadly, some of these patients will have permanent neurodegeneration from undiagnosed hypothyroidism.

Content provided by Datis Kharrazian, D.C., Mastering the Thyroid, Nov. 12, 2010