The topics of emotion, decision‒making, and consciousness have been traditionally dealt with in the humanities and social sciences. With the dissemination of noninvasive human neuroimaging techniques such as fMRI and the advancement of cognitive science, neuroimaging studies focusing on emotions, social cognition, and decision‒making have become established. I overviewed the history of social neurosciences. The emerging field of social brain research or social neuroscience will greatly contribute to clinical psychiatry. In the first part, I introduced our early fMRI studies on social emotions such as guilt, embarrassment, pride, and envy. Dysfunction of social emotions can be observed in various forms of psychiatric disorder, and the findings should contribute to a better understanding of the pathophysiology of psychiatric conditions. In the second part, I introduced our recent interdisciplinary neuroscience approach combining molecular neuroimaging techniques（positron emission tomography：PET）, cognitive sciences, and economics to understand the neural as well as molecular basis of altered decision‒making in neuropsychiatric disorders. An interdisciplinary approach combing molecular imaging techniques and cognitive neuroscience and clinical psychiatry will provide new perspectives for understanding the neurobiology of impaired decision‒making in neuropsychiatric disorders and drug development.