The COMT rs4818 G allele has been associated with higher levels of S-COMT in PFC [29], higher COMT activity, lower PFC dopamine signaling, and less efficient planning and problem-solving ability when there is no emotional feedback, but it could be more favorable in decision-making, which includes emotional processing [27], and also with treatment resistance in schizophrenia [30] and severe negative symptoms and anhedonia in schizophrenia [31]. This evidence concerns the gene COMT and schizophrenia.