The endophenotype is a measurable component which is characterized as an intermediate part of the path existing between the genotype and phenotype of a disease. In the context of psychiatric pathologies, an endophenotype is such if it shares inheritable variations with it, if it is evident both during the active and inactive phases of the pathology, if it is co-transmitted in the family, and if it is evident in both affected family members from pathology, and in healthy people. This review reports the available literature data of the interesting combination between endophenotype and psychiatry.