Diffusion tensor imaging (DTI) is used frequently to explore white matter tract morphology and connectivity in psychiatric disorders. Connectivity alterations were previously reported for bipolar disorder, unipolar depression and schizophrenia. However, there is limited data on how these disorders differ from one another in terms of connectivity.

In this study, we aimed to explore connectivity differences between these disorders.

We analyzed DTI data of 37 patients with schizophrenia, 41 patients with bipolar disorder and 46 patients with unipolar depression. Group analyses were performed for schizophrenia versus bipolar and bipolar versus unipolar contrasts with using age as a covariate.

Threshold corrected results showed that connectivity at internal capsule and corpus callosum were most distinctive between groups. For corpus callosum (splenium), unipolar group showed the highest connectivity and schizophrenia group showed the lowest connectivity (Fig. 1). For internal capsule, schizophrenia group had the highest connectivity and unipolar group had the lowest connectivity (Fig. 2). Bipolar group had intermediate values for both tracts.

These results indicate that connectivity analysis may be helpful for differentiating psychiatric disorders.