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White Matter Abnormalities May Allow Clinicians To Better Differentiate Unipolar Depression From Type-II Bipolar Disorder

July 3, 2021

A research team from the University of Pittsburgh Department of Psychiatry, led by assistant professor of Psychiatry, Anna Manelis, PhD, have identified that white matter abnormalities in specific microstructures of the brain may help to differentiate between diagnoses of bipolar disorder type-II and unipolar depression. 

Dr. Manelis and colleagues examined white matter microstructure differences in cohorts of individuals with clinical diagnoses of bipolar disorder type-II and unipolar depression and in a cohort of healthy control subjects. The study looked at variations in fractional anisotropy, radial diffusivity, axial diffusivity, and mean diffusivity. White matter reorganization expressed as decreases in fractional anisotropy and increases in radial diffusivity was observed in both the bipolar and unipolar groups versus the healthy controls in multiple areas of the brain. Differences were noted between the bipolar and unipolar groups in the areas of the left arcuate fasciculus, and at the junction of the right arcuate, the inferior fronto-occipital, uncinate fasciculi, and the forceps minor. 

The two disorders often have clinically overlapping symptom expression, which can make accurate diagnosis difficult to achieve. Given that effective treatment strategies for each disorder require patients to be accurately differentiated, Dr. Manelis and colleague’s research efforts may lead to more precise and efficient diagnostic testing and differentiation of the two disorders in the future.

The study was published in March in the journal Scientific Reports.


Manelis A, Soehner A, Halchenko YO, Satz S, Raozzino R, Lucero M, Swartz HA, Phillips ML, Versace A. White Matter Abnormalities in Adults With Bipolar Disorder Type-II and Unipolar Depression. Sci Rep. 2021; 11(1): 7541.

More About Dr. Manelis

Learn more about Dr. Manelis and her work as the primary investigator of the Anticipation, Cognition, and Emotion (ACE) Laboratory.