While a higher reactive state of microglia could be a plausible explanation for the hippocampal deviations, positron emission tomography (PET) studies of recent years that targeted the translocator 18 kDa protein (TSPO) did not find significant—or found only minor microglial—changes in recent-onset or established schizophrenia patients [138,139,140,141]. This evidence concerns the gene TSPO and schizophrenia.