The work tackles the pecularities of the defective state onset with 200 patients, diseased with the paranoid schizophrenia before the age of 25. The study of initiating and predisposing exogenous and endogenous risk factors of early defect onset (1-3 years) of patients has been performed, as well as the symptoms and syndromes which, in our opinion, also constitute risk factors for the early defective state onset and have an unfavourable prognosis. The adduced data can be used in determining the prognosis of schizophrenic defect probability at the first three years of disease.