A retrospective study of pre-manifest personality traits in 120 young patients (16-25 years old) identified the clinical heterogeneity of the period preceding the first episode of juvenile endogenous attack-like psychosis. Depending on the degree of personality abnormalities, patients were stratified into 3 groups as having accentuated personality traits, personality disorders (psychopathy) or pseudopsychopathy, the latter divided into deficit and degenerative subgroups. Correlations between the degree of personality abnormality and the type of manifest episode and its nosological status were found.