Researchers from the Mayo Clinic have identified six proteins as potential biomarkers for bipolar I disorder. These proteins, if validated, could help in the diagnosis and treatment of the mood disorder.

There are currently no biomarkers for bipolar disorder and other mood disorders. In diagnosing mood disorders, psychiatrists observe patients for symptoms and assess them through interviews. They then compare their notes with a set of diagnostic criteria to determine the patients' particular mood disorder.

However, this has a downside. The treatment for bipolar disorder is different from that of others, and the medications also vary. Some medicines may not be suited to other mood disorders. Thus, it is important to make an accurate diagnosis of the patient's condition.

"The potential of having a biological test to help accurately diagnose bipolar disorder would make a huge difference to medical practice," Dr. Mark Frye, lead study author and head of psychiatry at Mayo Clinic, said in a news release. "It would then help clinicians to choose the most appropriate treatment for hard-to-diagnose individuals."

The researchers conducted a feasibility study involving 288 study participants. Of these, 46 had been diagnosed with bipolar I depression, 49 with bipolar II depression and 52 with unipolar depression, while 141 did not have any mood disorder and served as controls.

The participants' blood samples were analyzed. A total of 272 proteins were investigated, and 73 of them differed from the others. However, six proteins from patients with bipolar I disorder stood out from the rest.

The researchers said the study is among the first "to assess the feasibility of high throughput multiplexed immunoassay technology (272 proteins) trying to distinguish different types of mood disorders."

They added that the six potential biomarkers need to be validated by replicating the study using a larger sample size. This would show if the six proteins are truly associated with bipolar I disorder.

The study was published in the Dec. 8 issue of the journal Translational Psychiatry.