IGF-1 levels were elevated in our Japanese patients with schizophrenia who had a mean illness duration of 14.8 years, whereas IGF-1 levels were not altered in Turkish patients with schizophrenia who had a mean illness duration of 11.8 years31 or Japanese patients with schizophrenia who had a mean illness duration of more than 10 years33. This evidence concerns the gene IGF1 and schizophrenia.