Background and goals: Recent studies indicate that basic self-disorder (SD) is a core clinical phenotype of schizophrenia and its spectrum. The goal of the present study was to test the degree to which SD characterizes the pre-onset phase of schizophrenia-spectrum disorders (SSD). A secondary goal was to replicate previous findings regarding the long-term stability of SD. Method: To accomplish these goals, the long-term association of SD in adolescence with SSD seven years later was examined in a sample of 39 non-psychotic, help-seeking adolescents. SD was assessed with the Examination of Anomalous Self-Experience (EASE), and presence of schizophrenia-spectrum and other co-morbid illnesses in young adulthood was assessed with the Operational Criteria+ (OPCRIT+) checklist for psychotic and affective disorders. Results: Nine (23.1%) of the 39 participants were diagnosed as suffering from SSD (three Schizophrenia, three non-organic and non-affective psychotic disorder, and three schizotypal disorder) in young adulthood. A diagnosis of SSD in young adulthood was significantly predicted by SD, but not by prodromal symptoms in adolescence. The correlation between the EASE total score at adolescence and young adulthood was moderate and significant (r = 0.64, p < .001). Conclusions: These results provide first long-term prospective support, in a sample not enriched for risk for psychosis, for the possibility that SD is a clinical marker of risk for SSD. Also, they provide additional support for the longitudinal persistence of SD over time.