By LAUREN CAHOON, RADHA CHITALE, and AINA HUNTER
ABC News Medical Unit

The stereotype of the tortured artist shows up often in popular culture: a frazzle-haired composer pacing about his room, a troubled starlet, a crazed novelist with a bad case of writer's block.

Along with that stereotype comes an assumption -- that the hyper highs and crushing lows that we witness in some of our celebrities is a sign of bipolar disorder.

In fact, it's rumored that many of the notable artists in history -- including Beethoven, Lord Byron and Charles Dickens -- suffered from the disorder.

THURSDAY, Feb. 28 (HealthDay News) -- Biomarkers in the blood associated with mood disorders have been identified by Indiana University School of Medicine researchers, who said the finding may change the way bipolar illness is diagnosed and treated.

The researchers analyzed blood samples from 96 patients and found varying levels of the biomarkers in participants with high or low mood states. They also found that concentrations of the biomarkers varied, depending on the severity of depression or mania or a patient's individual experiences.