Schizophrenia is the most frequent and disabling mental illness, particularly in young people, because of the precariousness and social exclusion it entails. Despite scientific advances in care and management to improve the quality of life of the person suffering from this type of disorder, schizophrenia remains a disease with a prognosis and an unlikely evolution that varies from one person to another. This variation responds to several factors both intra and extrinsic.This book is a collection of the results of an epidemiological study on relapse, which is one of the poor prognostic factors in the evolution of schizophrenia. This study was carried out on a population of subjects suffering from schizophrenia followed and managed in the psychiatric hospital of Sidi Chami of Oran in Algeria. The aim of this work is to present the different prognostic factors of schizophrenia relapse in order to improve the quality of care and life of the person suffering from this disorder.