A study that investigated the role of monocytic TLR4 signalling in cognitive deficits in schizophrenia groups (tardive dyskinesia and nontardive dyskinesia) showed that high TLR4 protein expression (MFI in the monocytes) was associated with lowered reasoning, problem-solving, and overall cognitive performance [72], and high mRNA expression [71], with a decline in social cognition and processing speed in patients with schizophrenia. This evidence concerns the gene TLR4 and schizophrenia.