Objective: Schizophrenia and other psychoses have devastating personal and social impacts and many efforts have been devoted to study prodromal syndromes for psychosis in order to achieve earlier detection and interventions. However, only few studies have been performed in developing countries on this subject, and there is a dearth of evidence in the Iranian population. In this study, we focused on conversion rate to psychosis and changes in prodromal symptoms in a group of first-degree relatives of patients with schizophrenia and to compare the conversion rate in those with and without prodromal symptoms as assessed by the Structured Interview for Prodromal Syndromes (SIPS) and Scale of Prodromal Symptoms (SOPS). Method: Participants were the first-degree relatives of hospitalized patients with schizophrenia at Roozbeh Hospital, Tehran, Iran. At baseline, a trained psychiatrist interviewed the participants using the SIPS and the SOPS and assigned them to high- or low-risk groups either based on the presence of prodromal criteria or seeking mental health services. After 12 months, the same examiner re-evaluated the participants in order to determine the changes in their symptoms and identify the probable transitions to psychosis. Results: One hundred participants, 50 participants within each of high- or low-risk groups, were recruited at baseline. Eight participants dropped out of the study. At the follow-up, the rate of transition to full psychosis among high-risk group was 13 (95 CI 0.029, 0.23), whereas none of the low-risk participants developed psychosis. None of the high-risk participants demonstrated attenuation in their prodromal states after a one-year follow-up. In contrast, of the 50 low-risk participants, three experienced prodromal symptoms for psychosis during this period. High-risk participant's illustrated higher severity in almost all of the SOPS items compared to the low-risk participants at both baseline and follow-up evaluations. Conclusion: Prodromal syndrome for psychosis based on the SIPS and the SOPS was a predictive factor for transition to psychosis after a 12-month period in a group of first-degree relatives of patients with schizophrenia admitted to a psychiatric hospital in Iran. Conducting further studies on this at-risk population is highly recommended in order to provide practical methods for early screening and therapeutic interventions
