Rapid eye movement sleep behavior disorder (RBD) occurs idiopathically (iRBD), frequently representing a prodromal phase of Parkinson's disease (PD). Previous reports have described that patients with PD have premorbid personality profiles such as industriousness, inflexibility, cautiousness, and lack of novelty seeking. As well, psychological stress often aggravates RBD symptoms. These phenomena encouraged us to investigate personality profiles in iRBD patients.