What is serotonin in bipolar disorder?

The serotonergic system is a diffuse network in the central nervous system that plays a major role in mood regulation, particularly low mood and depression. The main agents for treating depression are antidepressants, including selective serotonin reuptake inhibitors or combined serotonin/noradrenaline reuptake inhibitors. The mechanisms of these antidepressants result in increased synaptic levels of serotonin and/or noradrenaline.

What is the evidence for serotonin changes in people with bipolar disorder?

Moderate quality evidence suggests increases in serotonin receptors (5-TH1R) in the hippocampus, parahippcampus, and amygdala of people with acute bipolar depression compared to controls. There were also increases in serotonin transporters (SERT) in the cingulate and insula of people with acute bipolar depression. Most patients were unmedicated.

Low quality evidence is unclear of changes in serotonin receptor or transporter levels in people with acute bipolar mania.

December 2021

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Last updated at: 6:19 pm, 9th December 2021
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