In a multicenter, randomized, double-blind, placebo-controlled, 12-week, phase II trial, patients with schizophrenia who received 40,000 IU recombinant human EPO for 3 months with a weekly short (15 min) intravenous infusion were found to experience a significant benefit compared to that of controls in cognitive test package, including Repeatable Battery for the Assessment of Neuropsychological Status subtests (delayed memory, language-semantic fluency, attention) and Wisconsin Card Sorting Test-perseverative errors (p = 0.010) (104). This evidence concerns the gene EPO and schizophrenia.