Neural markers identify individuals at risk for Bipolar I

Bipolar (BD) is a psychological problem that can have profoundly negative consequences. People who have BD often have difficulty coping with the high and low moods that accompany the illness. They have higher rates of employment issues, relationship problems, drug or alcohol misuse, and suicide attempts than individuals without BD. Early diagnosis of BD is essential to adequately manage the symptoms and achieve a positive outcome. However, the symptoms of BD can easily mimic other mental health challenges such as depression and make early and accurate diagnosis elusive. Rather than relying on symptomatology alone, Robin Nusslock of the Department of psychology at Northwestern University in Illinois theorized that neural markers obtained through brain scans could provide evidence of individuals at risk long before the full onset of symptoms.

To test this theory, Nusslock enlisted 58 individuals with a history of BD II or cyclothymia, two mood conditions thought to precede BD I, and 59 participants with no history of any mental issues. The participants underwent left-frontal cortical electroencephalograms and were followed for nearly 5 years to determine if the baseline scans would provide evidence of later BD I onset. The results revealed that the participants who progressed from BD II or cyclothymia to bipolar I had more activity in the left-frontal and left-mid-frontal region of their brains than those who did not.

Nusslock also discovered that the participants with the highest levels of left-frontal cortical activity also had the earliest onset ages for their respective mood issues. Because age of onset is often used as an indicator for risk, this finding provides support that neural markers may also be valid tools used in combination with other assessments to make early diagnoses of BD I in those most at risk. Nusslock also noted that unlike the decreased cortical activity present in unipolar depression, the participants who eventually developed BD I presented with increased cortical activity at the beginning of the study period. Nusslock added, “Future research is needed directly comparing individuals with bipolar disorder and unipolar depression on both resting and task-related EEG.”