Emil Kraepelin’s dichotomy, which has been providing a basis for psychiatric classification, has been valid for many years. However, dimensional approaches based on the recent evidences from genetic, biological and clinical researches are in agreement, putting forth the need of this dichotomous view’s revision for consideration. In particular, failure of describing many of the psychiatric cases in nature with descriptive paradigm used for psychiatric classification in clinical practice hinders clinicians’ effort for developing a common language and leads to the questioning of psychiatric diagnoses’ stability. In fact, it has been stated that the descriptive validity was low in the patient group with both psychotic and affective symptoms. It has also been informed that bipolar disorder and schizophrenia were presented with common symptom clusters in the studies evaluating the patterns of clinical symptom clustering with factor analysis. Moreover, some of the candidate genes developing susceptibility for each disorder have been shown to be common in the recent genetic studies, suggesting there is an overlap between these disorders. It appears that dimensional approach suggested by geneticists is consistent with the data from clinical researches. In the light of these clinical and genetic evidences, famous German scientist Emil Kraepelin’s ground-breaking dichotomous approach in psychiatry should be revised after a century. Who knows if Kraepelin was still alive, maybe he would change his dichotomous view after a while.