To search for potential behavioral consequences of MMP‐9 rs20544 variants, we conducted a phenotype‐based genetic association study (PGAS) in schizophrenia patients from the Göttingen Research Association for Schizophrenia (GRAS) data collection (Begemann et al, 2010; Ribbe et al, 2010). This evidence concerns the gene MMP9 and schizophrenia.