In 1959, Brown observed the schizophrenic out-patients who return to the family home suffer relapses more than those who return to other types of homes. This heralded the appearance of a new ethiological theory placing the blame on the family, like other theories of the time. However, the search for the cause of these relapses was directed not towards the origin of the condition, but towards the interaction of the patient with the family which produced the relapse. This new focus placed emphasis on the course and not the root of the condition. Thus Expressed Emotion (EE) appeared, formed by criticism, hostility and emotional overinvolvement. Today it is recognised that patients in a family with high EE are up to four times more likely to suffer a relapse than those in a family with low EE; EE has become currently the best-known indicator of relapses in schizophrenia. The great importance of Expressed Emotion (EE) as a predictor of relapses in schizophrenia has meant that from its beginnings, this construct has been validated by relating it to other variables which could affect relapses such as Crucial Events, the Affective style of the parents, the patient's symptomology, the family or the patient's social support, the psycho-physiological arousal of the patient, abandonment of medication, etc. EE has been shown to be independent of all these variables in its relationship with relapses. Therefore its value as a predictor of relapses is evident.