The cause of bipolar disorder remains unknown after years of research, with sufferers experiencing sudden mood swings and often struggling to find adequate treatment. However, a new study has found that stem cells taken from bipolar patients behaved differently from those taken from people without the disease - a breakthrough for future research that may change the way the disorder is studied and treated. 

The researchers first took skin cell samples from people with and without bipolar disease, manipulating them back to the induced pluripotent stem cell (iPSC) stage - marking the first time that bipolar-specific stem cells have been forged. They then monitored the gene expression of the stem cells prior to manipulating them again to become neurons. Upon the later transformation, the researchers measured the gene expression again, noting that the iPSCs and neurons alike both behaved differently in bipolar patients and individuals without the disease. From this, they could ascertain that bipolar disorder is likely rooted in early brain development, which could influence not just the development of bipolar disorder but indeed a range of mental illnesses. The stem cells and neurons also, significantly, responded differently to lithium, the most common drug used to treat bipolar disorder. 

"We're very excited about these findings. But we're only just beginning to understand what we can do with these cells to help answer the many unanswered questions in bipolar disorder's origins and treatment," said the study's co-leader Dr. Melvin McInnis, professor of bipolar disorder and depression at the University of Michigan Medical School.

Dr. McInnis' colleague and study co-leader Sue O'Shea, PhD, echoed his enthusiasm. "This gives us a model that we can use to examine how cells behave as they develop into neurons," said O'Shea, director of the University of Michigan Pluripotent Stem Cell Research Lab and a professor in the department of cell and developmental biology. "Already, we see that cells from people with bipolar disorder are different in how often they express certain genes, how they differentiate into neurons, how they communicate, and how they respond to lithium."

The outcome of the study is encouraging for future research, paving the way for a closer study of the development and treatment of bipolar disorder. 

The study was published in Translational Psychiatry on March 25 2014.