IL-6 and IL-18 Important in Rapid Cycling Bipolar Disorder

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IL-6 and IL-18 Important in Rapid Cycling Bipolar Disorder

Rapid cycling bipolar disorder is identified as when a person experiences four or more distinct episodes of either mania or depression within a one year time period. Although not hugely common, it is estimated that 1 in every 100 people suffers with the disorder.

Previous studies have identified a link between immune dysregulation and cytokine levels within the condition; however these were based upon case control studies which were limited by methodological difficulties. New research published in October’s edition of ‘Brain, Behavior and Immunity’ (1) sought to identify varying cytokine levels when a person is in a state of rapid cycling bipolar disorder when compared to healthy control subjects.

Plasma samples were taken from 37 patients with rapid cycling bipolar disorder and measured for IL 6, IL 10, IL 18, IL 1b and TNFa and compared to 40 healthy aged and gender matched control patients in a 6-12 month longitudinally designed study. Adjustments were made for demographic, clinical and lifestyle factors.

When comparing manic and depressive states, investigators reported that levels of IL 6 (p<0.05) and IL 18 (p<0.05) were significantly elevated when the patient was experiencing a manic or hypomanic state. It was also found that when compared to healthy subjects, unadjusted levels of IL 6 (p<0.05) and IL 18(p<0.05) were elevated in manic/hypomanic bipolar disorder patients.

Researchers disclosed that levels of IL 10 and IL 1b were undetectable in the majority of samples, as well as finding high TNFa assay variability.

These results show clinical significance as they support the role of the immune response in rapid cycling bipolar and suggest that IL 6 and IL 18 could be markers of manic episodes meaning that a person with suspected bipolar can be more quickly diagnosed.


1. Brain, Behavior and Immunity

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