At the 117th annual meeting of the Japanese Society of Psychiatry and Neurology (JSPN), I received the 2020 JSPN Award for Special Contributions to Psychiatric Research for five papers published in 2020. Due to length limitations, I report on two of these papers in this article. First, I introduce a study on white matter microstructural alterations in psychiatric disorders using diffusion tensor imaging. In the large-scale analysis, we found that alterations in white matter regions in patients with schizophrenia and those with bipolar disorder have similar pathophysiological features, whereas alterations in patients with autism spectrum disorder and those with major depressive disorder are minor and their biological features may be similar to those of healthy subjects. These findings are expected to be useful for the development of objective diagnostic methods for psychiatric disorders. Next, I introduce a study that showed impaired deviance detection in patients with schizophrenia using mismatch negativity, one of the event-related potentials measured by electroencephalography. In the study, we found that the reduction of mismatch negativity amplitude in patients with schizophrenia is due to the impairment of a component related to prediction. Although it is known that mismatch negativity amplitude is reduced in patients with schizophrenia, it was unclear whether the reduction in mismatch negativity amplitude is due to impaired deviance detection or adaptation mechanisms. These findings are expected to be useful in elucidating the pathophysiology of schizophrenia and to be applied to future studies for the development of novel treatments.
 Author's abstract