Acknowledging the heterogeneity of research findings in the study of postmortem brain from individuals with schizophrenia, and recognizing that we observed a decrease in total NR1 protein overall, we tested if NR1 may be decreased rather than increased in PSD-enriched fractions derived from prefrontal postmortem tissue from the same brains we studied previously.14 To aid in the interpretation of our finding, we also measured levels of PSD-95 protein. This evidence concerns the gene DLG4 and schizophrenia.