Some papers reported that more homozygous Val/Val in catechol-O-methyltransferase (COMT) Val158Met genotypes were found (31 vs. 17%) in the non-deficit schizophrenia patients compared to the deficit schizophrenia subgroup [59], and SNP8NRG241930 in NRG1 were associated with non-deficit schizophrenia [60]. This evidence concerns the gene COMT and schizophrenia.