<prompt> A 17-year-old boy is diagnosed with schizophrenia. What is the risk that one of his siblings will develop the disease?25920  <response>: The risk of developing schizophrenia in first degree relatives of schizophrenic patients is elevated compared to the risk of the general population 0.9. Parents of schizophrenic patients have a lifetime prevalence of 11, and siblings have a prevalence of 9. Identical twins have a 50 chance of suffering from schizophrenia if their sibling has it. Children of schizophrenics have a lifetime prevalence of 12.8. Reference: Kaplon and sadock, 11 th edition, synopsis of psychiatry, 11 th edition, pg no. 310 