Men and Women Differ When it Comes to Bipolar Biomarkers

Credit to user Healthmindandkat. Used with permission under a Creative Commons license.

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!