Men and Women Differ When it Comes to Bipolar Biomarkers

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According to a new study by an international team of researchers, men and women have different reactions to compounds associated with immune system response to bipolar disorder. This is exciting news! The findings mean that bipolar disorder can one day be diagnosed by biological measurements in the body, and that approaches to treatment can be tailored differently for the sexes.


Researchers have long known that bipolar disorder manifests differently in men and women. This suggests that different biological processes underlie the condition in the two sexes. Additionally, the immune system activates during periods of mania or depression, and previous studies have demonstrated that immune system activation starts low-level inflammatory process in the brain, which is harmful. This inflammation may contribute to poor function among bipolar sufferers.

The immune system works differently in men and women as well. Researchers decided to measure immune system factors in men and women with bipolar disorder to see if reliable markers for the diseases could be found.

Scientists measured concentrations of zinc and neopterin–both associated with inflammatory processes–in blood samples of both men and women experiencing manic or depressive episodes, as well as from healthy controls. Zinc is a mineral needed by a healthy immune system to function properly, while neopterin is an immune marker secreted by white blood cells when the immune system is activated.

The 27 people with bipolar disorder recruited for the study had lower levels of zinc in their blood than the 31 healthy controls. There was no difference in neopterin levels. However, when women had more zinc in their blood, their depression was worse, whereas men’s mania was worse if they had higher concentrations of neopterin.

Zinc deficiencies have been associated with depression in the past, so the findings were surprising. Scientists are now measuring zinc levels in the brains of mice with inflammatory depression to see if higher levels of zinc in the blood means less in the brain.

The findings do not suggest that people suffering depression should take zinc, however.

What the international team that contributed to this study is ultimately hoping for is to discover a blood marker that can help predict bipolar episodes, and whether treatment is working. Exciting news!

Six-Year Delay Between Onset of Bipolar Disorder and Diagnosis, Study Finds

depression new
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A new international study conducted by researchers in both Australia and Italy has found that there’s an average of six years between the onset of bipolar disorder and diagnosis of the disease. An analysis of 9,415 patients from 27 studies, the largest of its kind, the study notes that crucial opportunities to catch bipolar disorder at its onset, when mood episodes aren’t as severe, are being missed.


While patients with concurring disorders such as psychosis do generally receive timely treatment, most people suffer for years before being able to address their mental illness with proper medications and therapies.

Professor Large, a psychiatrist at Prince of Wales hospital, claims that the delay is most severe for young people, whose symptoms may be attributed to teenaged moodiness. Diagnosing a bipolar depressive episode is also difficult, as that is often mistaken for unipolar depression.

Doctors have to look to detailed medical histories of their patients, as well as symptoms triggered by external events, such as manic or hypomanic phases triggered by antidepressants.

Molecular Mechanism Behind Lithium’s Effectiveness Identified

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Scientists have identified the molecular mechanism behind lithium’s effectiveness in treating bipolar disorder in an international study published in Proceedings of the National Academy of Sciences (PNAS). Researchers at Sanford Burnham Prebys Medical Discovery Institute (SBP), Yokohama School of Medicine, Harvard Medical School, and UC San Diego collaborated on the study, which used human induced pluripotent stem cells (hiPS cells) to map lithium’s response pathway.

Lithium is a salt which has long been considered the gold-standard for bipolar treatment. The side effects–such as nausea, weight gain, and birth defects–are a trial for many people who take the drug. Only about one-third of people who suffer from bipolar disorder respond to lithium treatment. Before researchers at the Salk institute developed a test to predict who will respond to lithium with 92 percent accuracy, there was no test, and the drug’s effect was only found through a trial-and-error process which could take months or years.

In the study, scientists used hiPs cells created from lithium-responsive and non-responsive patience to observe a physiological difference in a protein called CRMP2: the protein was in a much more inactive state in responsive patients. However, when the researchers applied lithium, CRMP2 worked properly. So the study shows that bipolar disorder has a physiological–not necessarily genetic–cause.

This study is the first to explain the molecular basis of bipolar disorder. Scientists hope to use the results to develop a blood test for the disease, as well as further tests that can predict whether people who suffer from bipolar disorder will respond to lithium. Research leading from this study may also discover safer and more effective drugs to treat the disorder.

Edited to Add: Here is the link to the study, as requested.