The Expressed Emotion index is a concept which refers to the quality of primary milieu involvement with the psychiatrie patient. Scoring is achieved on the basis of a semi-structured interview recorded on audio tape. The concept has undergone an extensive development in particular in the anglo-american research literature and has resulted in certain conceptions regarding schizophrenia, chiefly its recidivism, the development of intervention methods which reduce significantly the psychosis recidivism, and the construction of two measures displaying reliable quality. The threshold bas arrived for further clinical and ambulatory application of these measures and techniques.